CHAPTER 2

''Soil is the stomach of the plant".

- Aristotle

Can we hit at the stomach of the ~lant without hiitinsr at our own stomach?

THE EXPERIMENTAL SOILS

THEIR TYPES AND DISTRIBUTION IN CHHATTISGARH REGION

CHARACTERIZATION,STUDIES OF

MINERAL CONSTITUENTS

l1ICRO-NUTRIENTS AND MICRO-POLLUTAf/TS

HUI11C ACID

BACTERIAL POPULATION

18

2.1 THE SOILS OF CHHATTISGARH REGION

INTRODUCTION

The Chhattisgarh region located in the south-eastern

part of the Madhya Pradesh State comprises the seven revenue

districts of Raipur, Durg, Bilaspur, Raigarh, Rajnandgaon,

Sarguja, Bastar and Balaghat as shown in Fig.2-1. The soils

occurring in the region have been found to differ widely in

their characteristics, colour, texture reactions etc. The

soils of the region are divided between four locally named

categories called Bhata, Matasi, Dorsa and Kanhar.

It wi 11 be relevant to describe some important

parameters related to the physical properties of the soils

are:soil texture and soil structure. Soil texture is

concerned with the size of mineral particles present in the

soil. Specifically, it refers to the relative proportion of

the particles of various sizes in a given soil. Soil

structure is the arrangement of the soil particle into groups

or aggregates. These properties are helpful in determining

not only the nutrient supply ability of soil solids but also

. the supply of water and air which are so important to plant

life. As soils are composed of particles varying greatly in

size and shape. Specific terms are needed to convey some idea

of their textural make-up, and to give some indication of

their physical properties. For this. soil textural

class-names such as sand, sandy loams, and silt loam have

been used. Three broad and fundamental groups of soil

textural classes have been recognised as described below

HHATTISGARH REGION

0 'JOI{m I • t 6 t I

Sou,cf'-

Index

So.h

d S•ndy So~•

Ail Mtil<l Sotlt ll"d \Jw $.~ ~ t.RI Nrw Dt>Jh,. 1970

Fig. 2-1 TEXTURE BASED DISTRIBUTION OF SOl LS

IN THE CHHATTISGARH REGION.

19

20

Sands : The sand group includes all soils whose sand contents

make up 70% or more of the material by weight. The properties

of such soils are, therefore, characteristically sandy in

contrast witb the stickier nature of the heaviour groups of

the soil.

Clays A soil to be designated a clay must carry at least

35% of the clay-separate, and in most cases not less than

40%. In such soils, the characteristics of the clay-separate

are distinctly dominant, and the class name is sandy clay,

silty clay, or, the most common of all, simply clay.

Loams An ideal loam may be defined as a mixture of sand,

silt and clay particles which exhibits light and heavy

properties in about equal proportions. Roughly it is half­

and-half mixture on the basis of properties. Most soils of

agricultural importance are some type of loam. In most cases,

however, the quantities of sand, silt or clay present require

a modified textural class name. Thus, a loam in which sand is

dominant is classified as sandy loam. In the same way there

may occur silt loams, silty clay loams and clay loams (1).

One of the most significant indirect effects of soil

texture is through its control of the structure. Roots

require space for growth, and this space is provided by the

pores and fissures in the soils. Plant roots extend into the

soil in search of both water and nutrients. Since most roots

are of the order of 1-5 mm in diameter, and the pores in the

soil are rarely more than 1.0 mm in size, roots can only grow

21

by forcing their way into the soil. A critical factor,

therefore, is the ability of the soil to give way in the face

of limited pressure which can be exerted by the tips of the

growing roots. This in turn depends upon the consistence and

bulk density of the soil. The percentage of pores of

different size reported in soils of different textures have

been shown in Table 2-1 (2).

Table 2-1 PERCENTAGE OF PORES OF DIFFERENT SIZE IN SOILS OF DIFFERENT TEXTURES.

"Pore classes

Macropores (60 um)

Mesopores (2-60 um)

Micropores (2 um)

Sandy loam texture

33

33

33

Percent pores

Clayee texture

10

40

50

lt has been shown that real roots can extend into a

sandy soil only if the bulk density is less than

1.7-1.8 g -3 em and into a clayee soil only at bulk density

less than 1.5-1.6 g -3

em ( 2) . Compacted soil-horizons,

therefore, present a formidable barrier to root growth. In

the same way, high bulk densities limit seedling growths. The

consistence of the soils tends to decrease as the moisture

content increases; as the soil receives weter, root- and

seedling-growth become easier (2). The salient morphological

features of the four major types of soils of Chhattisgarh

region have been described in Table 2-2. The texture-based

Table 2-2

S.N. Morphological features

Colour

2. Texture

3. Structure

4. Consistence

22

SALIENT MORPHOLOGICAL FEATURES OF THE PRINCIPAL SOIL TYPES OF CHHATT I SGARH REGION.

Soil types

Bhata

Reddish, dark reddish, brown

Gravelly coarse, loamy to sandy

Massive (Structure­less)

Matasi

Yellow

Sandy loam

Angular blocky

Nonsticky Slight & non-platic sticky

Dorsa

Brownish grey

Silty clay

Kanhar

Dark grey, brown to black

Clayee

Sub-angular Angular to angular blocky

Sticky and very plastic

Very sticky and plastic

5. Lime concretion Absent Absent Present Abundant

6. Other concretion Ferruginous gravel

7. Reaction with HCl Non effer­vescence

8. Cracks

9. Depth

10. Internal drainage

Absent

Very shallow

Rapid

or very few

Few iron Numerous concretion iron

Numerous black iron

Effer­vescence in last horizon

Few line cracks

11oderate

Moderate

concretion concretion throughout

Effer­vescence throughout

Wide vertical cracks

11edium

Moderate to slow

Efferves­cence throughout

Bharka or sink hole

Deep

Slow

23

distribution of soils in the Chhattisgarh region has been

shown in Fig.2-1.

The district-wise distribution of the four principal

types of the soils reported ir:; the Chhattisgarh region have

been shown in Table 2-3 (3).

The physical characteristics of soils which have

significant role in supporting the plant life have been

explained below :

Bulk density : This is the mass of the dry soil per unit bulk

-3 volume (g em ) including the air space. The bulk volume is

determined before drying the soil to constant weight at

Infiltration rate : It is a soil characteristic describing

the maximum rate at which water can enter the soil (em hr- 1 )

under specified conditions including an excess presence of

water •

. Field capacity : It is the percentage of water remaining in

soil 2 or 3 days after having teen saturated, and after free

drainage from the soil has practically ceased.

Wilting point It is the r.Joisture content of the soil, on

oven-dry basis, at which plant (specifically sun flower

plants) wilt and fail to recov:r their turgidity when placed

in a dark humid atmosphere.

Table 2-3

District

Raipur

Durg

Bilaspur

Raigarh

Surguja

•

DISTRICT-WISE DISTRIBUTIOfl OF DIFFERENT SOILS Ill • CHHATTISGARH REGION (in lakh hactares)

Bhata

1.50 •• (15)

1.12

(20.4)

1. 56

(15)

1.16

(20)

a. 40

(35)

Matasi

4.09

I 40)

1. 37

(25)

2.59

(25)

2.90

(50)

2.06

( 30)

Dorsa

2.04

I 20)

1.11

(20.2)

2. 07

(20. 2)

1.45

(25)

1.37

(20)

Kanhar

2.55

(25)

1. 90

(34.5)

1. 90

(34.5)

0.29

(5)

1.03

(15)

Total cultivated area

10.22

5.51

10.37

5.81

6.86

Statistics of Balaghat and Bastar Districts have not been shown . ••

24

The parantheses show the percentage of the total land of the region

Available water : It is the portion of water in soil that can

be readily absorbed by plant roots. This is defined by most

workers as that water held in the soil against a pressure

upto 15 bars (1).

The physical characteristics reported (1) to be

assigned to the four types of the soil have been shown in

Table 2-4.

2.2 SOILS OF TRE CHHATTISGARH REGION:THEIR TESTING AND CHARACTERIZATION

INTRODUCTION

The soil testing gives a measure of the availability

of the nutrients to the crops. It is multi-purpose in nature.

Among other things, it aims at : (i) Grouping the soils into

classes relative to the level of nutrients. (ii} Predictir;g

the probability of getting profitable r.esponses in terms of

the crop yield. (iii) Helping to evaluate soil properties,

and (iv) Determining the specific soil conditions like

alkalinity, salinity and acidity which limit corp yield (4).

The significanc~ of the physico-chemical ch-aracter is tics

experimentally determined here has been described below :-

Ta

ble

2

-4.

SE

LE

CT

ED

P

HY

SIC

AL

P

RO

PE

RT

IES

O

F TH

E

PR

INC

IPA

L

SO

IL

TY

PE

S

OF

CH

HA

TT

ISG

AR

H

RE

GIO

N.

S.

N.

Ph

ysic

al

So

il

typ

es

pro

perti

es

---~

Bh

ata

M

ata

si

Do

rsa

K

an

ha

r

1.

Nech

an

ica

l co

mp

osit

ion

(3

)

Sa

nd

6

0-8

0

30

-50

2

5-3

5

20

-30

S

ilt

15

-22

3

0-4

0

25

-30

2

0-3

0

Cla

y

9-2

0

20

-35

3

5-4

5

45

2.

Bu

lk

den

sit

y

1.7

6-1

,80

1

. 5

0-1

.65

1

.30

-1.6

5

1.3

0-1

.65

(g/c

m3

)

3.

So

il

dep

th

(em

) S

-30

3

0-8

0

80

-15

0

15

0

4.

In

filt

ra

tio

n

5.0

-7

.0

0.6

-3.0

2

.0-3

.0

2.0

-2.5

ra

te

(cm

/hr)

5.

Fie

ld

ca

pa

cit

y

(%}

5.5

2

17

.35

3

5.0

0

37

.00

6.

Wil

tin

g

po

int

(%)

3.

4 0

8.7

0

17

.50

2

0.2

0

7.

Ava

ila

ble

w

ate

r

(%}

2.2

0

8.7

0

17

.50

1

6.8

0

1\)

"'

27

The supply of the plant nutrients, and thus the

fertility of the soil is significantly affected by pH. The

solubility of most nutrients varies in response to pH. Most

of the nutrients become more soluble as pH falls, and thus

they are released more rapidly in acid conditions. As acidity

increas'es, however, the losses of the nutrient by leaching

increases also, and thus their availability to plants may

actually be decreased. In other cases, the quanti ties of some

nutrients may rise to such large extents under acid

conditions that they become toxic to plant. In addition, we

may note that soil acidity also affects the activity of soil

organisms-a factor which indirectly influences soil

fertility. For these reasons, one of the main aims of soil

management is to control the pH, and maintain a slight

acidity in the otherwise neutral soils (2).

Electrical conductivity The measurement of electrical

conductivity is used as means of apprising soil salinity. The

electrical conductance, expressed in mS -1

em increases with

soluble salt contents, and thus •lllows simple interpretation

of the readings ( 5). Saline soils include those soils

containing salts in quantities sufficient to interfere with

the growth of most crop plants, but not containing enough

exchangeable sodium to alter the soil characteristics

is appreciably. Technically, a saline soil ·defined as a soil

having a conductivity of the saturation extract greater than

4.0 mS

15 (5).

-1 em and an exchangeable sodium percentage loss than

Organic carbon

organic matter.

28

Carbon is a common constituent of all

Consequently, its movements during the

microbial digestion of plant tissues are extremely

significant. Much of the energy acquired by the fauna and

flora within the soil comes from the oxidation of carbon. As

a result; its oxide is evolved continuously in large amounts.

The various changes this element undergoes within or without

the soils are collectively described in what is known as the

·carbon cycle. The soil is the main source of C02

gas,

although small amount of it are excreted by plant roots, and

are brought down in rain water. Under optimum conditions, as

much as 45.5 Kg of carbon dioxide per acre per day may be

evolved. The carbon dioxide from the soil ultimately escapes

to a large degree into the atmosphere where it may again be

used by plants thus completing the cycle. The degradation of

the organic matter also results in the formation of other

carbon products. Elemental carbon is found· in soils to a

certain extent, and its presence in soils is considered

significant. Under certain conditions, methane and carbondi­

sulphide may be produced in small amounts in soils. But, of

all the simple produ.cts, carbondioxide is by far the most

abundant ( 1).

Available nutrients : The plant growth depends upon the

supply of a range of plant nutrients, many of which are

derived from the soils. Numerous factors inf 1 uence the

availability of plant nutrients. In the case of those

nutrients, such as nitrogen supplied by biological process of

fixation and mineralization, the biological properties of the

29

soils are particularly important. In the case of minerals,

such as phosphorus and potassium, a more crucial factor is

the rate of ions released from their source minerals. A pool

of readily available nutrients occurs in the soil solutions,

and these are supplied to the plants directly. When these are

drawn out from the· •SOil solutions, more nutrients are

released from the reserves held by adsorption on the

colloidal particles. Thus, most nutrients occur in three

forms: (i) available nutrients which are dissolved in the

soil water, (ii) exchangeable nutrients which are held on the

surface of colloidal particles (iii) labile nutrients which

are held within the soil minerals, and released

weathering. The rate of release of nutrients from

by

the

exchangeable reserve into the soil solution is sufficiently

rapid to meet the needs of the plants. The rate of

replenishment of the exchangeable reserves by minerals from

the labile pool is slow,however. Consequently, over time ·the

exchangeable reserves tend to be depleted,

became exhausted (2).

and the soil

Cation Exchange Capacity : The plants need C, H, 0, P, K, N,

5, Ca, Fe, Mg, Mn, Cu, B, Zn, Co, Mo, Cl, Na, and probably

several other elements which are yet to be confirmed. A small

but an important fraction of the total of the elements

present in soil minerals occurs as readily exchanyeable or

adsorbed ions. These forms of the elements are of vi tal

importance to the nutrition of the plants on

different soils. The mineralogical composition of soils thus

30

has an important bearing on soil productivity. The rate of

release of ions slows down as the soil minerals become highly

weathered, often becoming too slow to support intensive crop

production. The electric charge on the soil particles is

neutralised by an equivalent amount of oppositely charged

ions, the so called exchangeable ions held to the surface by

mainly Coulomb forces.

The most common exchangeable cations of soils are

+ + + + 2+ 2+ 2+ Ca ' Mg ' K ' H ' Na • and NH . Ca generally is the

4

dominant ion. In very acid soils, Al(OH)+ 2

may constitute a

considerable part of the counter ions,. the proportion

increasing with falling pH. In alkali soils, the content of

+ Na is exceptionally high. Common anions are

2-HOP4 , HC03 and anions of humic acids.

Cl ,

Though some of

these anions do not always function as exchangeable ions, but

are nearly always present in the soil solutions. The

capacities of soils to adsorb and exchange cations and anions

vary greatly with the content of clay, organic matter and the

mineralogical composition. The Cation Exchange Capacity (CEC)

is defined as the amount of cation species bound at pH 7.0 or

another sui table pH, depending on the method used for its

measurement. It varies slightly with the bonding strength of

the ions, and increases with the content of clay and organic

matter. The CEC of mineral soils may range form a few to

50-60 meq/100 g, whereas the CEC of organic soils may exceed

200 meq/100 g (5).

31

Silica : Free silica occurs in the soil mainly in the form of

quartz (Si02

), consisting of a continuous frame-work of

silica tetrahedra. Free silica also occurs in some soils. It

also occurs in some soils as cristobalite. Substituted

cristobalite occurs with varying substitutes (NaAL, SiJ02 , in

which the Na is exchangeable. In certain soils, cristobalite

may take up nearly 50% of the clay, the other half being

quartz (6). Exchange capacity of the clay arises almost

entirely through the substitution in cristobalite. Free

silica particles provide the frame-work of soil structure,

and influence the soil formation. Quartz occurs in the

majority of the soils, and makes up from 50 to 90% of the

sand coarser silts of many soils.

Iron oxide The most common· iron oxides in the soils are

hematite (Fe2o

3) which gives pink to bri9ht red colour to the

soils, and goethite (Fe2o

3.H

20J which gives brown and dark

reddish colour to the soils. Iron oxides provide an extremely

important reflection of the chemical properties of the soil

and the genetic processes that have governed the soil"

formation ( 7-9). In poorly drained organic soils, the

occurrence of FeOOH, an isomer of goethite, has been reported

(8). It gives a brown orange colour to the soils. Iron

oxides of the soils are usually the products of weathering of

iron-bearing minerals. Hematite may also be inherited from the

parent rocks.

32

Aluminium oxides The crystalline mineral. gibbsite Al (OH) 3

(or Al2o

3.3H

20), is the most abundant hydrous oxide of

aluminium in soils occurring primarily in soils of tropical

and sub-tropical region which have undergone intensive

leaching of silica. Clay formation is enhanced by Al2

o3

-

content of the parent material of non-resistant minerals.

High porosity which enhances the water holding capacity was

found to enhance clay formation (5).

The physico-chemical characteristics of the four soil­

types (Ebata, Matasi, Dorsa, and Kanhar) have been determined

and described below.

MATERIALS AND METHODS

Soil Sampling from Farm-Fields Three farm-fields (2 to 4

hactares each) were identified in each of Chandkhuri,

Lakholi, Arang and Kurud villages in the Raipur Tehsil and

District of the Chhattisgarh region of Madhya Pradesh. These

villages are known for the occurrence of Bhata, Matasi,

Dorsa, and Kanhar types of soils respectively·. Thin slices of

soils were taken out with the help of a spade from the plow­

layer of each field at intervals of 20 steps, and a total of

30 samples were collected from each field. The samples

collected from each village were composited and brought to

the laboratory for chemical analysis (10). The collected

samples were first air-dried. The bulk samples were then

passed through a sieve (6 mm). partitioned, and quantities

(about 1 Kg each) were retained. The samples were then

further subjected to the processes of grinding.

33

sieving (4mm and 2mm) and partitioning, and representative

samples of about 100 g in each case were obtained. The

samples were then heated in oven at 110°C for 3 hours, and

used for analysis.

Procedure The determinations were carried out as described

below :

I!.!!.: A soil-water suspension (1:5 by wt.) was prepared, and

the pH was directly recorded using a pH meter (Systronic

Model 324) ( 11).

Electrical conductivity : The electrical conductivity of the

soil suspension ( 1:5 by wt.) prepared in conductivity water

was measured using a conductivity meter (Century Model

CK- 71 0) ( 11) .

Organic carbon : Weighed quantities (1 g each) of the samples

were transferred to Erlenmeyer flasks after pretreatment with

sulphurous acid to decompose the carbonates present. 10 ml of

chromic acid solution (34% Cro3

in H20- H

3Po

4 medium) was

added, followed by the additionof 50 ml of 112_504

- H3

Po4

(1:1

mixture). The mixture was

··free air through

bailed for 5 minutes using a flow

the reaction mixture. The evolved

co2

was absorbed in 25 ml of 0.5 N NaOH solution placed in a

conical flask. 15 ml of 0.1 M BaC12

solution was then added

to precipitate the carbonates. The excess Na0/1 was back

titrated with standard 0.5 IJ I!Cl using phenolphthlein

solution as an indicator. Fromthe weight of co2

forncd, the

amount of total organic carbon was calculated (10).

34

Total nitrogen Weighed quantities (5.0 g each) of the

finely powdered form of the samples were placed in Kjeldahl

digestion flasks. 20 g of sodium sulphate and a pinch of

cuso4

.SH2

0 were then added. This was then followed by an

addition of 35 ml of conc.H2so

4• The mixture was digested tor

30 minutes in low flame, and then for another one hour at

full flame. The flask was then cooled, and 300 ml of ammonia­

free water was added cautiously, and the mixture was further

cooled. The contents were transferred to a distillation

flask, and ammonia was distilled after the addition of NaOH

solution (40%) into the distillation flask. The evolved

ammonia was absorbed in 25 ml of boric acid solution (4%)

placed in a 500 ml conical flask with 4 drops of bromocresol

green methyl red indicator solution. The boric acid was then

back-titrated with standard hydrochloric acid solution (0.788 N)

( 10).

Total phosphorus : Weighed quantities (2 g each) of the

finely powdered samples were transferred to a 300 ml conical

flask. The sample was heated on a hat plate with 20 ml of

cone. HN03

for the oxidation of the organic matter. Then 30

ml of HC104

solution (60%) was added and the mixture digested

in a fume cupboared for 40 minutes. After cooling, 50 ml of

distilled water was added, and the mixture was filtered into

a 200 ml volumetric flask. An aliquot of this solution was

used for the analysis by the phasphavanadamalybda tc me thad.

Far this purpose, the solutions were prepared by the

dissolution of 25 g of ammonium molybdate in 400 ml of water,

35

and 1.25 g of ammoniur.J metavanadate in 300 ml of water

acidified with 250 ml conc.HN03

. The two solutions were mixec

and diluted to 1 litre. An aliquot (10 ml) of the test

solution was placed in a 50 ml volumetric flask. The HNO,

acidity was adjusted to about 0.3 N. 10 ml of vanadomolybdate

reagent was added. and the solution diluted to 50 ml wi ti:

distilled water. The absorbance was measured at 470 nm. ,;

calibration graph was prepared using standard solutions of

KH2

Po4

, and the concentration of phosphorus was found out

using the calibration graph (10).

Total potassium Weighed quantities (0.1 g each) of finely

ground soil were placed in 30 ml of platinum crucible. Fe•

drops of distilled water were added followed by the addition,

of HF (5 ml). HN03

(3 ml), and HClo4

(1 ml). The mixture wao

heated on a sand bath till the contents were eva;;c:ated. The

crucible was cooled and the acid treatment was further

repeated till all the organic matter was completely removed.

The residue was dissolved in 5 ml of HCl (6 N) and 5 ml of

distilled water. The solution was filtered into a 50 ml

flask. Potassium was then determined using a flame photometer

(Systronics,l1odel 305), and a calibration graph prepared by

using standard solutions of KCl (12,13).

Cation Exchange Capacity Weighed quanti ties ( 5 g each) of

samples were placed in 100 ml centrifuge tubes, and stirrec

with 50 ml of sodium acetate solution ( 1 N) at p/1 5.0. Th~

soil-suspension was digested in water bath for 30 nin. T.~c

salts were renoved by centrifugation. Two additional ... J :: :-. l r. ....

36

using the same sodium acetate solutions and the same bath

treatment were also done. Thereafter, the samples were given

five washings using 1 N cac12

solution. The excess salt was

removed by washings with 80% acetone until the washings were

free from chloride. Finally, the calcium ions were replaced

by givin<; five washin~s with a neutral solution of ammonium

acetate (1 N). The calcium was then determined in the

solution using a flame photometer (Systronic,nodel 305) (10).

Exchangeable cations (Ca, Hg, K & Na) : Weighed quantities (59

each) of the samles were taken in 250 ml conical flasks and

mixed with 100 ml of ammonium acetate solution (1 N) and

allowed to remain in the suspension form for 10 min. The

suspension was then filtered and washed with the ammoniur.>

acetate solution. The filtrate was made upto 250 ml usin9 the

saLJe extracting solution. The extract was transferred to a

400 ml beaker, and evaporated to a small volume on a hot

plate. The contents were then transferred to a platinur.>

crucible and heated first slowly ana then to full red beat

for 20 min. The residue was taken up in 50 ml HCl solution

(0.1 N), and boiled to obtain a clear solution. Aliquots of

the solution were used for the estimation of Ca, !1g, Na, and

K. Na and K wre determined flamephotometrically, whereas Ca

and Mg were determined titrimetrically using EDTA (disodiur.J

salt) solution (0.01 11), NH3

/NH4

Cl as buffer (pli 10.0) and

Eriochrome Black T solution as indicator. The use of Patton &

Reeder's indicator was made to determine calcium, and tt.e

value of Mg was found out by takiny the di ffcrence between

the titre values (10).

37

Silica Weig/led quantities (5 g each) of soil samples were

repeatedly treated with an acid mixture of HCl and HN03

(3l1J

and evaporated to dryn.ess. The residue was then treated with

HCl (1:10), filtered, washed, dried and ignited in a platinum

crucible and weighed. The residue was further treated with

few drops of H 2

50 4

and then with HF, and ignited to a

constant weight. The loss in weiyht was ta-ken as that 5i02

(13).

Fe2

Q3

: The filtrate obtained after the removal of silica

made upto 250 ml in a volumatric flask. An aliquot of

was

the

sample solution, after adjusting acidity between 5-6 N with

respect of HCl, was treated with a concentrated solution of

SnC12

until the colour due to ferric ions nearly disappeared.

Few drops of stannous chloride solution were added in excess.

The excess of stannous chloride was removed by adding

mercuric chloride solution. The solution was then cooled,

25 ml of Zimmermann Reinhardt reagent solution was added, and

the mixture titrated with standardised KMn04

solution (0.05N)

(13).

Aluminium oxide : Weighed quantities (0.1 g each) of finely

powdered ,sample were fused with 0.1 g sodium carbonate in a

platinum crucible. After cooling, 8 ml of HC104

(60%) was

added and the contents were heated till white fumes of HC104

were removed. The crucible was cooled, 5 ml of dist1lled

water was added and boiled to dissolve the salts. The

contents were transferred to a centri fuye tube, r:>ixecl .,.i th

2ml of 1/Cl (6 II) and 60 ml of distilled water and :t:cn

centrifuged to throw down the silica. To the filtnte. ;,,, c 1

38

solution (1%) was added and the mixture centrifuged. 10 ml of

hot NaOH solution (25%) was added and the tube was placed in

hot water bath for 5 min., diluted with 50 ml of water and

centrifuged to throw down the Fe(OH)3

precipitate. An aliquot

of the supernatant liquid was transferred to a 100 ml beaker,

the contents diluted to 75 ml with 50 ml of distilled water,

pH adjusted between 2-3 using NaOH or HCl, and the aluminium

estimated spectrophotometrically using a+uminon reagent (0.8%

in amiJonium acetate HCl medium). The absorbance was recorded

at 520 nm. A calibration graph was prepared by usiny series

of standard solutions of K2so

4.Al

2(so

4)

3.24H

2o in water. The

standard solutions were treated with aluminon reagent as

described in the case of sample solutions (12,14).

The results obtained for the four types of the soils

have been shown in Table 2-5.

RESULTS AND DISCUSSION

Distinct natures based on the physico-chemical

characteristics have been observed in the four types, namely

Bhata, 11atasi, Dorsa and Kanhar soils of the Chhattisgarh

region. A gradation amongst the soil-types is evident froiJ

the data obtained. While the Bhata and 11atasi types have

indicated weakly acidic to almost neutral nature, the Dorsa

and Kanhar types

alkaline nature.

conductivity from

have indicated neutral

The gradual increase

Dhata to Kanhar

to a sliyhtly

in

types

electrical

indicated

corresponding increase in the electrolyte contents of the

39

Table 2-5 PHYSICO-CHEMICAL CHARACTERISTICS OF FOUR PRINCIPAL SOIL TYPES OF CHHATTISGARH REGION.

S.N. Parameters Soil types

Ebata Matasi Dorsa Kanhar

1. pH 5.70- 6.50- 7.00- 7. 40-6.50 7.00 7. 4 0 7". 60

2. Electrical 0.17 0.21 0.26 0.30 conductivity (m mhos/em]

3. organic 1. 40 1. 80 2.20 3.50 carbon ( %)

4. Available nutrients (ppm}

Nitrogen 193.00 275.00 333.00 441. 00 Phosphorous 3.60 13.80 17.90 16.10 Pot as 451.00 503.00 594.00 795.00

5. Cation Exchange 8.50 18.00 32.00 38.50 Capacity (m eq/100 g)

6. Exchangeable cations (m eq/ 100 g)

Calcium 4.80 9.50 22.60 29.00 Magnesium 2.40 4.80 7. 40 8.20 Potassium 0.20 0.10 0.50 1.20 Sodium 0. 4 0 0. 70 0.40 0.60

7. Si02

(%) 48.20 60.80 72. 10 68.10

8. Fe2o

3 (%) 36.00 17.00 8.80 11.00

9. Al2o

3 (%) 8.00 9.80 12.80 14.20

40

soils. The organic carbon which can be taken as an indicator

of humus substances of the soils was also found to be

increasing from Bhata t.o Kanhar types. Available nutrients

(N,K,P) showed highest values in the Kanhar type indicating

it to be the most fertile soil. The Cation Exchange Capacity

and the exchangeable cations (Ca, Mg, K and Na) have also

been found to be highest in the case of Kanhar soil.

On the basis of the highest values of electrical

conductivity, organic carbon, available nutrients, cation

exchange capacity, and exchangeable cations observed in the

case of the Kanhar soil, it can be considered to be fully

equipped and the richest of all the soils examined here. Such

a soil when exposed to interactions with the effluents of

diverse nature and compositions is expected to exhibit more

pronounced effects on its characters. Any damage undergone by

this type of superior soi 1 through the exposures of

industrial effluents shall be of great concern. In the work

carried out and described in the subsequent chapters, the

impacts of industrial effluents of a wide range of nature

mainly on the Kanhar soil have been investigated. However,

the basic principles underlying the damage-causing reactions

shall be applicable to any category of the soils.

41

2. 3 T/fE CHHATTISGARH SOILS: STATUS OF MICRO-NUTRIENTS AND MICRO-POLLUTANTS

INTRODUCTION

Out of all the elements known, seventeen elements have

been found to be essential to the plant growth. These

elements may be divided into two groups:macro-nutrients (C.

H, 0, N, P, K, Ca, Ng, and 5) and micro-nutrients (Fe, !Jn,

Cu, Co, Zn, B, Mo and Cl) (5).

MICRO-NUTRIENTS : Amongst the micro-nutrients, boron has

been found essential for the green algae and the higher

plants (15). Manganese is important to activate a number of

metalloenzymes such as arginase (urea formation), puruva to,

carboxylase. It is preferably accumulated in mitochondria,

and hence it acts as a co-factor in the respiratory enzymes.

While Mn (II) state is found in acid soils, 11n(IJI) and

Mn (IV) states are favourc,d pH and oxidisin~

conditions (16); Bromfield and Skirman (17) found that l1nS04

could be oxidised in the microbial presence of two

microspecies, Corynbacterium and Flavobacterium or

Chromobacterium. Although Mn(II) is oxidised to Mn(IV) in

soils, a concentration of 0.02 M of Mn(II) introduces

manganese toxicity resulting in the deminution of the

oxidation rate ( 18). The majority of the Indian soils

contains 300 to 1600 ppm of manyenose (19). Organic matter in

the soils affects the manganese transformations throuyh such

processes as complexation, diminution in the ox ida ti on

potential of the soil or stimulation of microbial activity

that results in the incorporation o[ manganese in biolc~zcal

tissues ( 16).

42

Copper is important in maintaining proper functioning

of metalloenzymes such as ascorbic oxidase, cytochrome

oxydase, celluloplasmine, lysine oxidase etc. ( 17) • Zinc

deficiency symptoms are reported to be acute where top soils

were removed for levelling purposes (5). Zinc is among the

micro-nutrients which are made available to the plants

through the supply of fertilizers. Its total absence can

cause crop failure. It can also become toxic to crops if

present in large quantities ( 20). Although significant

quantities of iron ore present in soils, this element is

regarded as micro-nutrient in view of the very small amount

of this element being taken up by the plants. The approximate

weight of iron removed by average crops has been reported to

be 0. 5 kg/hactare, although iron may be present in the soils

in the range 2000-10,000 kg/hac tare (20). Plants differ in

their ability to take up iron from soils. Very litt.le is

known about the concentration of iron in the soil solutions

but it is probably present as inorganic complexes. The roots

of certain categories such as water culture plants have been

reported to excrete soluble organic compounds into the soil,

that form soluble complexes with iron available at the

surface of iron(Ili) hydrous oxides (21). Suitable iron

chelates such as ferric citrate and tartarate and ferric-EDTA

have been reported to be added to soils to ensure the supply

of this element to the plants (22). The role of iron in the

formation of chlorophyll was discovered long a9o. In India,

the deficiency of iron in soils has been reported frol':l

Punjab, 1/aryana, Uttar Pradesh, Rajasthan and Velhl. The 1 ron

43

deficiency is called iron chlorosis which results in the

yellowing of the plants due to lack of chlorophyll (23).

The reservoir of cabal t in many soils is reported. to

be that adsorbed on the surface of manganese oxides, the

availability of cobalt is decreased by any soil-treatment

which converts the manganous ions to insoluble oxides, and is

increased by those treatments which convert manganese oxides

to manganous ions (24). It is reported that biological

nitrogen fixing system needs cobalt along with iron and

molydenum (25, 26). Cobalt in the form of its sulphate is

usually added to correct the cobalt deficiency of soils (27).

Molybdenum is needed for symbiotic nitrogen fixation. It is

also required for the reductionof nitrates in plant tissues.

2-It is taken up as either HMoo

4 or Mo0

4 (28). The reservoir of

molybdate is that adsorbed on the surface of ferric oxides or

hydra ted oxides which have a very strong affinity for

molybdate (29). Molybdenum deficiency is normaJly found in

acid soils (30). The molybdenum content varies from 0.2 to

5.0 ppm with a mean value of 2 ppm (31).

Chlorine has in recent years been established as one

of the essential nutrients for plant growth. Wilting is

considered the most generaly symptom of chlorine deficiency.

Considerable work has been done on the toxicity symptoms

caused by excess presence of Cl. Generally, these symptoms

include burning of the leaf tips or margins, bronzing,

premature yellowing and abscission of leaves, and less

frequently chlorosis (23). There is no strOn<J evidence that

chloride has any specific effect on plant yrowth, though it

44

may some time hasten maturity. Its main [unction, for which,

however, it is not specific, is on osmotic pressure regula tor

and cation balancer in the cell sap and in the plant cells

(32).

Excess supply of one or more of the above stated

micronutrients often results in depression in growth rate,

and visual pathological effects which at time are

chracteristics of elements supplied in excess (23).

MICRO-POLLUTANTS:THEIR INDUSTRIAL SOURCES AND UPTAKE BY PLANT SPECIES

Apart from micro-nutrients, the soils may also receive

some elements which have no established role in the plant

growth. No beneficial effects of these elements on the plant

growth have been reported. On the contrary, these elements

have been reported to result in damage to the plants in one

or more ways. Some elements of this nature are being

described below.

Arsenic bas been described has poisonous to the plants

(35). Arsenic exists in nature in -3, 0, +3, and +5, state, is

stable in aerated water, whereas elemental arsenic and arsine

(AsH3

) exist in reducing sediments. In moderately reducing

environment, the trivalent state is found to occur ( 34).

As(III) is known to be highly toxic, while As(V) is known to

be less toxic. Arsenic can be removed from solutions in the

As(V) state by adsorption on activated solid~. Ar~enic is

very common element present in nearly all soils, and hence 1n

plants and animal products. At 1 ppm an below, there 1 , nc

45

known harmful effect of arsenic 135). Sodium arsenite is

reported to have been used for many years as a weeo killer

136, 37). More recently organic arsenic compounds such as

cacodylic acid has been found useful as general contact

herbicides to control, weeds, particularly grasses 138,39).

Soils near some smelters are often polluted with large amount

of arsenic I 39). Methylation ot~ dimethyl arsenic acid, whi.ch

is also used as a pesticide, is evident in soils treated with

this pesticide (40). A strain of methanobacterium is reported

to produce dimethylarsine from arsenate (41).

Extensive work has been done about the presence of

lead in air, water and soils. It has been remarked that

modern man contains 100 times more lead than pre-historic man

(42). The average concentration of lead in soils is reported

to be 16 mg/kg. Brown algae and phytoplankton have been

reported to show an affinity for lead (43). It will be useful

to take into account the environmental pollution by cadmium,

zinc and lead attributed to the largest lead-zinc smelter

plant of Japan located at Annaka city. Here about 500 samples

of soil and 80 samples of agricultural products were analysed

for Cd, Zn and Pb. A high correlation was found to exist

between the content of Cd, Zn, and Pb of soils and the

occurrences of these elements in the farm products I 44, 45).

In other words, the closer the soil and vegetation to the

smelter plants, the greater was the contamination found. The

concentrations of these metals in leaf vegetables were found

to be substantially hiyher than those in root ve~etablcs,

fruits and cereals. The flour fror.J wheat and barley were

found to contain r.Juch more Cd, Zn, and I'b than rJce 1n t.~c

46

same polluted area. The soil-profiles near the above-stated

smelter stack were also examined. The upper soil (0-10 em)

was found to be most polluted and soils deeper than 40 em

showed approximately the same values as in unpolluted soils

(44, 45). The toxic effects of lead on human body have been

described in Chapter 1 (Section 1.3). It has been estimated

that in USA, the man has a daily intake of approximately 300

ug of Pb (46), of which about 60% comes from the ingestion of

contaminated food ( 47). The lead-content of food has been

largely influenced by environmental contaminations. This may

have been through surface contamination as well as plant

tissue incorporation of lead that was deposited on soils or

crops grown in areas near the highways or lead smelters (48).

When such crops were used as forage for farm animals, the

lead was found transported into milk or meat (48,49). Amon9st

birds, ducks have been shown susceptible to poisoning from

the consumption of marsh soils ·contaminated with lead (50).

The soils near smelters contain far greater amounts of lead

than does the forage. It was found that horses which have a

marked tendency of. pulling grass along with the roots and

soils could digest far greater quantities of lead than would

be estimated from the analysis of forage alone (51). The

extent to which lead contamination in corn leaves from lead

smelter situated 75 meters away can occur is evident by the

reported presence of lead at a level of 3200 ug/g of the corn

leaves on dry weight basis (52). The lead presence in the

range 1 to 7000 ppm in the ash of a variety of plants [ron

the whole of USA was found in 761 out of 912 sanplcs (53). In

47

contaminated areas, the Pb-content may be much higher; cedar

trees in Missouri on a road side contaminated with lead-ore

dusts contained as much as 20,000 ppm in ash (54), and

Spanish moss near heavily t ravelled roads contained as much

as 15,000 ppm in ash (56). There is also report of bi a­

methylation of lead in environment. Any aqueous saline medium

would produce mono- and dimethyl lead( IV) species in the

soils. These species are known to decompose rapidly. (56).

According to Schroeder (57), tetraethyllead is 100 times more

toxic as inorganic lead.

Hercury compounds in the crust of earth are believed

to degrade to the metallic form which in turn is volatilized

to the atmosphere. The atmosphere contributes to the

world-wide distribution in the environment. Rain fall acts as

a scrubber of the atmosphere, and may deposit up to 500 "'Y

annually/acre on the arth surface (58,59). The levels of

mercury have been reported as follows: Swedish soil

50-510 ppb, England and Northern Ireland soils 5000-15,000 ppb

French and Sudan soils 10-60 ppb, (58, 59). Plant and animal

tissues also ahve been reported to have substantial amounts

of mercury with a wide range of levels (60). Some values are

as follows apples (New Zealand) 11-135 ppb, apples (U.K.)

20-120 ppb, rice (Japan) 227-1,000 ppb, rice (U.K.) S-15 ppb.

Schacklette (61) reported mercury in trees and shrubs that

grew over a cinnabar deposit in Alaska-ranye between 0.5-3.5

ppm on dry basis. As the absorbed mercury passes into blood,

one half of it is firmly bound to the albuminof plasr.a and

the other half is associated with the red cells (62). It ic.

therefore, readily redistributed to the tissues, and in a few

hour found in highest concentration in the kidneys. By the

end of a week, 85-95% of all the mercury in the body is

stored in the kidneys (63). Other details of the toxic

effects of mercury have been described in Chapter I (Section

1 • 3 ;'. In sulphide-rich anoxic sediments,. mercury

concentration becomes vanishingly small as a result of the

formation of HgS. In natural systems, bacterial methylation

of mercury occurs in sediments, mobilising the mercury and

making it available for biota (64,66). The evidence of the

formation Of mercury humate with purified humic acid

extracted from the river sediments has been reported (66).

Mercury is methylated in aquatic environment by biological

and non-biological processes that were discovered several

decades ago. Dimethyl mercury [(CH3

)2

Hg] and methyl mercury

cation +

[CH3

Hg] are both formed in nature (67}. Methyl- and

ethyl mercury which are soluble are carried and stored for

extended periods in the blood cells (68). Extremely high

toxicity of methyl mercury to man and its concentration in

the environment have been reported to be of particular

concern (69). Most of the mercury in the Ji Yun river

sediment was found associated with humic acid and other

organic substances (70). Humic acid present in the sediments

has also been found to dissolve mercury (II) sulphide. Thus,

mercury sulphide in the sediments mi~ht be mobilized and

cycled between the sediments and water column (71). The

adsoprtion capacity of different ad5orbents for mercury wa5

found to decrease in the following order : humic acid > /1n00

>

clay minerals > > The adr.orption of mercury

48

49

the main process for the enrichment of mercury in soils and

sediments (72,73). Humic acid in the river water thus

enhances the transport of mercury in form of soluble complex.

The stability of mercury humate in river .was found to be

greater than the stabilities of mercury chloride, hydroxide,

sulphate, or phosphate complexes (74). The emission of methyl

mercury· from the sediments into the water is reported to be

in -2 -1

the range of 0.4 to 5.0 ug Hg m day · (75).

The concentration of cadmium in most ~oils is reported

in -1 the range 0.5-1.0 mg kg although concentrations greater

than 20 mg kg - 1 occur naturally in some places. Raised

concent:ration results from smelting and mining activities,

and from the use of sewage sludge on land. The average

concentration of cadmium in the earth crust is 0.15 mg kr; -l

( 76). and the background concentrations found in soils

depenct upon parent material from which they are derived

( 77). Soils derived from igneous rocks are reported to

contain 0.1-0.3 mg Cd -1

kg (dry matter), from r.Jetamorphic

rocks

zinc

-1 0.3-11.0 mg kg (76).

ores, calamine

Cadmium is a contaminant of the

and sphalarite ( ZnS) • The

contamination of soil resulting from mining activities in

U.K. have been found to contain upto BOO mg Cd kg- 1 · (78).

Soils near the large zinc smelting complex in 1100 kg 2 area

in U.K. is -1 reported to have Cd-levels in excess of 4 mg kg

(79). Phsophatic fertilizer is another important source of Cd

in agricultural soils. Williams and David (80) reported Cd-

concentra tiorl.s o[ 5-100 mg -1 kg in rock phsophat-2, most or

all of which enters the fertilizer prepared fror:J it. The

background values o[ cadmium in a sel12ction of SO di[[ 12 rcnt

50

-1 plants have been reported in the range 0.02-1.00 mg kg (dry

matter) (81, 82). Jarvis et al. examined the distribution of

cadmium between the roots and shoots of 23 plants species

-1 after exposure to a nutrient solution containing 0.01 mg Cd L

In all, except three species, more than 50% of the Cd of

taken-up was re ttdned in the roots ( 83). In the case· rye

grass, approximately 80% of Cd was retained in the roots.

John (84) examined the distribution of Cd in a range of crops

y rown in soils containing 40-200 mg Cd kg -l soil. He found

that root-concentrations of Cd were found to exceed leaf

concentrations for all the crops tested. Using Cd 109 as a

tracer, Stenstrom and Lonsjo (85) found that 0.33% of Cd in

sludge-treated soil was recovered in wheat tops, but only a

quarter was found in the grain. Cadmium is a non-essential

element for both plants and animals, so there is no lower

critical concentration below which deficiency would ,:-::cur.

Upper critical concentrations marked the onset of toxicity.

Cd may be described as zootoxic since it is more toxic to

the animals than to the plants. So the zootoxic upper

critical concentration in plant-tissue precedes the

phytotoxic concentrations, and animals could conceivably be

harmed by eating apparently healthy plant material. Beckette

and Davis (86) found that at a median value -1 of 80 mg Cd kg

in tissues of young barley plants, the yield was found

reduced. For practical purposes, Yield is taken to be a

sensitive indicator of plant health, and reductions in yield

precede visual symptoms of Cd-toxicity as shown by chlorosis,

red brown patches on lcavc!:i, stunted !itCr:J!:i and. in !::C\•crc

51

cases, leaf curling and abscission (87,88). The long-term

exposure to enhanced level of Cd which is a cumulative poison

may be significant. Long lived animals such as humans are

more at risk to chronic Cd-toxicity than farm animals whose

life is comparetively short. Under normal circumstances, food

constitutes the most important source for the general

population. Over 50% of the total dietary intake of Cd is

derived from the cereals and vegetable portions of the diet

(89). WHO and US environmental agency have independently

estimated the safe limit of daily intake of Cd at about 70 ug

(90, 91). Cadmium is an element which is highly toxic to

mammals. In 1969, Tsuchiyia (92) reported that Itai itai

syndrome was associated with the ingestion of Cd-contaminated

rice together with other pre-disposing factors (93). It is

now well established that kidney dysfunction following

proximal tubule damage is the most characteristics symptom of

chronic poisoning by cadmium (94,95). Details of other toxic

effects of cadmium have been described in Chapter I (Section

1.3). There are reports of cadmium undergoing biomethylation.

The dimethyl cadmium hydrolyses quickly to a gelatinous

precipitate of polymeric CH Cd(OH) . This polymer is capable 3 X

of methylating aqua ted metal electrophiles such as Hg( II)

(96,97). Studies have also shown that cadmium is adsorbed on

clay minerals, hydrous oxides of iron and manganese, humic

substances which are all norr.Jal constitutents of the soil

(98,99). It is reported that the uptake and transport of

cadmium in plants is reduced at increased zinc or potassiu~

concentrations ( 100). !11]1: IIDU .~H ·.~ 111 r ll

T 133<5

The cadr.Jiur.J presence in

52

near Annaka city where Japan's largest zinc smelter is

located has been reported as follows (46) rice 0.4-0.95;

wheat 0.5-8.6; green vegetables 2.6-56.0; root crops 0.9-17.0

fruit vegetables 0.3-0.6; ppm (dry matter basis). In 1968,

Fukushima et al (101) analysed rice samples collected from 77

farm houses in different parts of the endemic area of Itai

i tai des ease in Japan, and also from control areas, and

obtained a correlation between the geographical distribution

of the prevalence of desease and the cadmium contents in the

soil and rice in the endemic area (102). The results of pot

culture experiments on rice plants and wheat preferred by

Kobayashi and Muramoto (103) in which different amounts of

cadmium and zinc were added to the soil indicated that the

more cadmium oxide added to the soil the greater was the

uptake Of cadmium especially in wheat, and that the yield of

wheat was reduced at a level of 0.003% cadmium in the soil,

while in rice a significant decrease in yield was not seen

until 0.1%. There is also a report of severe chlorosis of the

leaves of sweet potatos which turned bright yellow due to

cadmium poisoning in a cadmium mining district in Japan

(104).

Chromite (FeO.Cr2o

3) is the only important ore of

chromium, and approximately 0. 03% of the igneous rock in the

earth crust is chromium. The absorption, distribution and

of excretion.chromium by animal and man at levels beyond normal

ingestion have been well investigated (105). At the5e level~.

orally administered trivalent chromium is ab~orbed to tl:c

extent of only about 1% or Jess (106). J/cxavalcnt cl:ro~ 1 ~-

53

better absorbed than trivalent chromium (106), and readily

passes through the membrane of red blood cells and becomes

bound to the globin fraction of hemoglobin ( 107). The other

adverse effects of chromium have been described in Chapter I

(Section 1.3). The occurrence of chromium in plant tissues of . ' ' food and feed plants have been reported as follows: the

element has been detected in the range of Jess than 1 to

700 ppm in ash of a variety of native species found

throughout USA in 1096 samples. out of 1139 samples ( 108).

Chromium salts, particularly chromates, even at very low

concentrations, have been found to be toxic to plants ( 109).

Chromium (III) has been reported as an essential element for

man and animals required as part of the glucose tolerance

factor ( 110, 111).

Nickel is wide-spread in its occurrence, and

distributed widely in foods, Estimates of daily human intake

are from 0.24-1.0 Ni mg/day (112,113). Vegetable materials

contain much more nickel than material from animal origin.

Estimates between 0.15-0.35 ppm Ni have been made for foods,

tubers and grains ( 114, 115). Some i terns, high in Ni, were tea

7.6 ppm, buck wheat seed 6.4 ppm, oyesters 6.0 ppm, on dry

weight basis ( 115, 116). Significant concentrations of Ni are

present in DNA and RNA ( 117, 118). The harmful effects of

nickel on human health have been described in Chapter I

(Section 1.3). The occurrence of nickel in tissues of food and

feed plants in USA has been reported from 5 to 500 ppm in 82~

samples out of 912 samples on dry weight basis 1108). In ash,

Ni occurs in most samples of food plants in concentratJon o[

54

5 ppm, and rarely exceeds 100 ppm (119). An exception is

provided by soya bean seed samples in which Ni is found to

occur in the range of 30-500 ppm (in ash), in contrast with

corn grains from the same area in which Ni ranged between

5-70 ppm (in ash) ( 120). There is a report that cyanobacteria

brown and green algae and yeast cells all bioconcentra te

nickel (121).

The determinations of the mocronutrients and micro­

pollutants in the principle soil-types of Chhattisgarh region

have been described below.

MATERIALS AND METHODS

Sample collection The method of the collection of the

samples of the four principal soil-types (Bhata, 11?tasi,

Dorsa, and Kanhar) and the methods of sample preparations

have been described earlier (Section 2.2).

Method Manganese, copper, zinc, molybdenum, cobalt, lead,

cadmium, chromium, and nickel were determined in the soil

samples using an atomic absorption spectrophotometer. As and

Mg were determined spectrophotometrically.

Sample preparation Weighed quanti ties ( 5 g each) of the

samples were dried at 110°C in an oven for three hours. and

thereafter reduced to a powder form. Weighed quantity (0.5 9)

of samples were treated in a teflon diyestion bomb usin~ lOnl

acid mixture

C for

of /ICl, /IF, and 111103

and placiny in an oven dt

three hours (122). Sample ~olution for t~c

55

determination of Pb were made in a medium of 0.1 M EDTA to

suppress the interference of phosphate and fluoride (123).

Reagent solutions : For the AAS determinations, the standard

solutions of the respective metals were prepared by the

prescribed procedures (123) as follows

Manganese 1 g of the metal (wire form) was dissolved in

minimum volume of nitric acid (1:1), and the solution was

diluted to 1 L (1 ml = 1,000 ug Mn).

Copper 1 g at the metal wire was dissolved in minimum

volume of nitric acid (1:1), and the solution diluted to 1 L

(1 ml = 1000 ug Cu).

Zinc : 1 g of the granule was dissolved in 40 ml HCl ( 1 :1)

and the solution diluted to 1 L. ( 1 ml = 1, 000 ug Zn).

Molybdenum 1 g of tbe metal wire was dissolved in HCl acid

(1:1) with gentle heating. The solution was cooled and

diluted to 1 L (1 ml = 1,000 ug Mo).

Cobalt : 1 g of metal wire was dissolved in minimum volume of

nitric acid (1:1). and the solution diluted to 1 L (1 ml =

1,000 ug Co).

Lead,: 1 g of the metal-wire was dissolved in nitric acid (1:1)

and the solution diluted to 1 L ( 1 ml = 1, 000 ug Pb).

Cadmium·; 1 g of the metal was dissolved in minimum volume of

nitric acid (1;1). and the solution diluted to 1 1. ( 1 :-:1

1. 000 ug Cd).

56

Chromium:!-: 1 g of the metal wire-form was dissolved in HCl

acid (1:1) with gentle heating. The solution was diluted to

1 L (1 ml = 1,000 ug Cr).

Nickel : 1 g of the metal strip was dissolved in nitric acid

(1 :1), and the solution diluted to 1 L (1 ml = 1,000 ug Nil.

All the metals and chemical reagents used were of

spectroscopic grade. The water used was distilled and

deionised. The glassware used were superior quality

borosilicate.

Apparatus The analysis was carried out by using an atomic

absorption spectrophotometer (Varian Techtron Model AA 575).

The operating conditions of the instrument ( 123) have been

shown in Table 2-6.

During calibration the standard solutions of the

metals were suitably diluted to match the ocncentrations of

the sample solutions within the measurement sensitivity

( 124). The physical properties of the sample and standard

were matched closely to avoid matrix effect (124). The

methods were also suitably modified to remove the effects of

interference.

The results obtained have been shown in Table 2-7.

The determinations of arsenic and mercury were made

spectrophotometrically using the following procedures.

Cu

Co

Ni

Pb

Zn

11n

Cd

Cr

No

Wa

ve

Len

gth

32

4.7

24

0.7

23

2.0

21

7.0

21

3.9

27

9.5

22

8.8

35

7.9

31

3.3

-·~"n'""" t..uJVUlllUN~

OF

T

HE

A~OMIC

AB

SO

RP

TIO

N

SPE

CT

RO

PH

OT

OM

ET

ER

Sp

ectr

al

Ba

nd

P

ass

(nm

)

0.5

0.2

0.2

1.0

1.0

0,2

0.5

0.2

0.5

La

mp

C

urren

t (m

A)

Fu

el

3.5

7.0

3.5

ED

L.

C2

H2

!N2

0

C2

H2

C2

H2

C2

H2

5(o

r

C2

H2

ED

L)

5.0

c 2

H2

3.5

c 2

fl2

(or

ED

[,)

7.0

C

2f!

2/N

2o

7.0

C

2fl

2

Su

p­

po

rt

Air

Air

Air

Air

Air

Air

Air

Air

N2

0

Fla

me

Sto

ich

io­

metr

y

Oxid

izin

g

Oxid

izin

g

Oxid

izin

g

Oxid

izin

g

Oxid

izin

g

Oxid

izin

g

Oxid

izin

g

Red

ucin

g

Red

ucin

g

Op

tim

um

w

orkin

g

Ra

ng

e

(pg

/ml)

2-8

3-1

2

3-1

2

5-2

0

In

terferen

ces

In

terfe

ren

ce

wit

h

hig

h

Zn

/Cu

ra

tio

,rem

ova

ble

b

y n

itro

us

oxid

e

-acety

len

e

flam

e.

Ni

inte

rfe

res if

mo

re

than

1

50

0

ug

/ml

No

Ch

em

ica

l in

terfe

ren

ce.

No

ca

tio

nic

in

terferen

ces.

3-

2-

--

P0

4,

C0

3,

I ,

F

an

d

CH

3C

OO

su

pp

ress

ab

so

rb

an

ce

wh

ich

is

rem

ova

ble

b

y

use

o

f O

.lM

ED

TA

.

0.4

-1.6

N

o ch

em

ica

l in

terfe

ren

ce

1.0

-4

.0

No

Ch

em

ica

l in

terfe

ren

ce.

0.5

-2

.0

No

ch

em

ica

l in

terfe

ren

ce

in

air

-a

cety

len

e

fla

me

2.0

-8

.0

Co

,Fe

an

d

Ni

dep

ress

ab

so

r­b

an

ce.

Eff

ect

rem

ova

ble

b

y

the

use

o

f a

cety

len

e/n

itro

­u

s

ox

ide

15

-60

N

o ch

em

ica

l in

terfe

ren

ce.

"' 'ol

58

Arsenic A weighed quantity (5 g) of the soil sample was

transferred to a Kjeldahl flask and mixed with 20 .ml

concentrated sulphuric acid, 5 ml concentrated nitric acid

and 0.1 g of potassium chlorate. After completion of

digestion, mixture was cooled, filtered and diluted to 250

ml. An aliquot (25 ml) was placed in a arsine evolution

flash, treated with 5 ml concentrated HCl, 2 ml KI solution

(15%), and eight drops of SnC12

solution. After 15 min., 5 g

of pure granulated zinc was added to the solution. The arsine

evolved was absorbed in a si 1 ver diethyldithocarbamate

solution (5% in pure pyridine). The absorbance of the complex

was measured at 540 nm. A blank was also run. A calibration

curve was prepared by using standard solutions of arsenic

prepared by dissolving arsenious oxide in NaOH solution (13,

125).

Mercury : A weighed quantity (1 g) of the sample was

transferred to a Kjeldahl flask, 30 ml of 1:1 mixture of

cone. sulphuric and nitric acid was added, and heated for

two hours. The mixture was cooled, filtered and diluted to

250 ml. An aliquot (25 ml) was taken in a separatory funnel,

and 50 ml of dilute hydrochloric (20%) was added. It was then

treated with 10 ml of dithizone solution (0.25%) in

chloroform. Two more extractions were done. The organic laye::

was treated with 50 ml of hydrochloric acid (1:70/ and 5 ml

of KBr solution (40%) and shaken vigorously. The chloroforr:

layer containing copper was discarded. The aqueous phase

containing mercury was used for the 5pcctrophotor:etric

59

determination using dithizone reagent at pH 1-2 by measuring

absorbance at 485 nm (14).

The results obtained have been shown in Table 2-7.

RESULTS AND DISCUSSION

The results obtained (Table 2-7) show that the four

principal soi)-types (Bhata, Hatasi, Dorsa, and Kanhar) of

the Chhattis·garh region contain the selected micronutrients

(Zn,Cu,Mo,Co,Hn) at concentration 1 e vel s which have a

reasonable agreement with those reported for the soils of

Madhya Pradesh State and in the neighbouring area (25). The

status of the selected micronutrients in the soils here can

thus be taken as normal.

Apart from the micronutrients, the soils have

indicated the presence of a number of metallic elements which

have no direct role in the plant growth. On the other hand,

some of these elements e.g. Cd, Ni, Cr have been reported to

have a tendency of getting into the plant body, and farm part

·of the food chain. However, cadmium which has been found to

be very sensitive element from the point of view of plant

uptake, particularly by the paddy crops, has been found to be

present at low concentration levels (1.0-2.0 ppm).

60

Table 2-7 CONCENTRATIONS OF MICRO-NUTRIENTS AND MICRO-POLLUTANTS (ppm} IN PRINCIPAL SOIL-TYPES OF CHHATTISGARH REGION.

Elements Concen tra ti ons found analysed

Bhata Matasi Dorsa soil soil soil

HICRO-NU:TRIENTS

Zn 78.0 62.0 52.0

Cu 89.0 71. 0 60.0

Mo 3.S 3.0 2.5

Co 22.5 18.0 15.0

Mn 962.0 764.0 644.0

MICRO-POLLUTANTS

As 5.0 5.0 5.0

Cd 2.0 1.5 1.0

Pb 85.0 67.0 57.0 ** Hg Nil Nil Nil

Ni 69.0 55.0 46.0

Cr 56.5 45.0 38.0

* Correspond to black clay of Haharashtra.

** Nil denotes undetectable.

Concen tra ti on ranges rep or te,d in M.P. soils

Kanhar (Ref.23) soil

* 55.0 39.0-60.0

63.0 22.4-63.8

* 2.5 Trace-1.20 * 16.0 50.0-64.0

682.0 484.0-1540.0

5.0

1.5

60.0

Nil

49.0

40.0

61

2.4 HUMIC ACID ITS ISOLATION FROM PADDY SOIL (KANHAR TYPE) AND CHARACTERIZATION.

INTRODUCTION

Humus has been defined as the substance left after the soil

organisms have modified it from the original organic matter to a

rather stable group of decay product. In other words, humus is th·e

colloidal remains of organic matter. Soil organic matter has been

defined as any living or dead plant or animal materials in the soil.

Organic matter is often confused with humus, because organic matter

consists of either living or dead plant or animal materials. Hence it

must contain all the nutrients needed for the growth of these

organisms. The amount and type of these nutrients are directly

dependent on the original source. In raw (undecomposed) organic

matter, there are few major groups of organic compounds which are

contributed to the soils. These are : carbohydrates, lignins,

proteins, fats, waxes and resins. Of these, carbohydrate end proteins

are the most important and most readily decomposed. These two

constituents are also the greatest contributors of soil nutrients

such as nitrogen, sulphur and phosphorus. Lignin is a very resistant

compound which persists in the soil as one of the main component of

the humus. Fats, waxes and resins are resistant compounds which

contribute sulphur and phosphorous to the soil. Alongwith these major

compounds, there exists a host of other minor compounds. Unless the

organic matter is decomposed, these nutrients will remain i:: the

soil, but in unavailable form. The decomposition of organic matt;,r i~

carried-out by soil organism (22). The nuclei of humus arise both

from altered lignin compounds and through the ::;ynthesis of arc::a tlc

62

compounds by micro-organisms. Micro-organisms are thus

implicated in all phases of humus formations. They affect the

decomposition of the original plants and animal residues to

simpler compounds, and at the same time are responsible for

the alteration of lignin and tanin molecules which will

become parts of the structural units of humus. Several

hypotheses have been proposed about the nature of humic

substances. Most of these hypotheses have several aspects in

common:humic substances are amorphous, three-dimensional,

polymeric, acidic substances, of high molecular weight, with

more or less aromatic nature. It is also generally agreed

that no single specific structural formula will adequately

represent the humic substances. Rather most hypotheses

suggest a type or a skeltal structure in which only general

aspects are included. The hypotheses differ primarily in the

nature of structural nucleus whether it is benzenoid~

phenolic, quinonic, or heterocyclic in nature, whether the N

is a fundamental part of such nucleus or an accidental

contaminant or whether there is a reasonable degree of

uniformity as reflected in a number of structural units

randomly distributed throughout the nucleus (25). Humus was

regarded as a soil constituent of great significarce in soil­

forming processes, and in soil fertility; its presence in tbe

soil was the qualitative feature distinguishing the soil from

the parent rock. Efforts to quantitatively isolate humus

matter in a form suitable for analysis have had only a

limited success. Most schemes of separation involved the

63

solubilisation of organic matter through the alkaline,

neutral extracting reagents and various organic solvents

( 25).

Humic material primarily consists of negatively

charged colloids. Some of it is bound to the clay through

polyvalent cations such as calcium or aluminium, one of whose

charges neutralise a negative charge on the clay and the

other on a humus. Some is bound to positively charged

surfaces of iron or aluminium hydrated oxides, and some is

held at clay surfaces through hydrogen bonding or by van der

Wall forces. The classical way of separation of humus part

from soil that is most widely used is to extract the soil

with sodium hydroxide (0.1-0.5 N) • This replaces the

polyvalent ions by sodium and precipitates them as

hydroxides, or converts the alumina to the aluminate anion.

It increases the negative charge on humus colloid and

decreases the positive charge on any sesquioxide surfaces. So

far as the humus is bonded to the clay through polyvalent

cations, a treatment with chelating agent such as sodium

pyrophosphate will be an effective dispersing agent ( 126).

The classical method for fractionating the humic colloid

dispersed in sodium hydroxide extract is to acidify the

suspension with sulphuric or hydrochloric acid, which causes

a part of dispersed organic matter to precipitate. The part

that stays in solution is known as fulvic acid, that which·

precipitates out as humic acid, and that part of the organic

matter which docs not disperse in the alkali but re,ain~ in

the soi 1 as humin. Although these fractions arc

64

definite names, they are not homogenous. Each contains

par ti cl es with a wide range of molecular weight and

constitution, nor there is a clear cut division between the

fractions. Also, the proportion of humic matter that is

precipitated by the acid depends on the type of acid used and

its strength.

The humic colloides (or humic acids) are built-up of

carbon, oxygen, hydrogen, nitrogen, sulphur and phosphorus;

and, as far as is known, no other element forms an integral

part. The elemental composition of humus from different soils

varies within quite wide limits, but for many agricultural

soils, the ratio C:N:S:P is of the order 100:10:1:2 on a

weight basis. The dispersed humic particles have a wide range

of molecular weight, but there is still some difficulty in

separating the humic suspension into fractions ·having a

molecular weight in a given range. The molecular weights of

humic acids have been found to be above 5000 and going to

several millions ( 127). Humic colloids contain a range of

polysaccharides, proteins or polypeptides and substances of

unknown compositions, but rich in aromatic rings, as wel_l as

a large range of substances present in small or very small

quantities. This includes waxes and asphalts on the one hand

(127), and substances likely to be present in the living

cells in the soil organisms such as purin and pyrimidine

bases and nucleic acids (128) on the other.

Humic substances are able to form complex linkages of

various kinds with metals by ion-exhange, adsorption on

65

ourfaces and formation of chelates. Cation exchange reactions

are important in plant nutritions. According to the different

types of linkages between functional groups of humic acids

and the inorganic soil constituents, three main types of

metal-organic derivatives can be distinguished ( i) the ionic

type with participation of carboxyl and phenolic hydroxic

groups leading to the corresponding humates by the known

reaction of salt formation, (ii) the semi-polar type, formed

by co-ordination linkages with participation of amino, imino,

keto and thioether groups, leading to the complex compounds

of chelate types, (iii) a type that is formed by polarisation

effects and hydrogen bridge linkages with special

participation of terminal functional groups forming compounds

of the adsorption type (129).

The infrared spectroscopy of humic acid preparations

and their fractions is used by many authors

characterizing humic substances of different soil origins

( 129). The assignment of different specific bands is limited

by the fact that soil organic matter preparations represent

in most cases mixture of more or less complex molecules

containing different types of linkages and functional groups.·

This leads to an overlaping of the absorption bands. The

infrared absorption spectra of humic acid, therefore, shows

only some bands which are characteristic for the chemical

nature of the molecule. The infrared absorption properties of

the samples are also strongly influenced by different methods

of sample preparation (130).

66

The isolation of the humic acid from one variety of

the paddy soils (Kanhar type), and its subsequent characteri-

zation by IR-spectroscopy has been described below.

MATERIALS AND METHODS

Sample collection The method of the sample collection of

the Kanhar variety fo the paddy soil has been described

earlier (Section 2.2).

Isolation of humic acid A weighed quantity (200 g) of the

soil was extracted with 2 litres of sodium pyrophosphate •

solution (0.1 M) in 0.1 M sodium hydroxide medium (pH 13.0).

The supernatant was collected by centrifugation. The extract

was acidified with H2

so4

to a pH of 1.5 which yielded

precipitated humic acid.

Purification of humic acid The humic acid obtained was

purified by repeated flocculation and peptisation using

dil.H2

so4

and NaOH till free form metal and sulphate ions.

The product was further purified in a batch of flasks

containing Dowex-15 cation exchange resin until no further

decrease in its pH was noticed. The ash content in a small

portion of the purified humic acid was determined, and the

value of the same was found to be 0.25%. The total wei<;;ht of

humic acid after oven drying at was recorded (131,

132).

67

IR-spectra of isolated humic acid The IR-spectra of the

isolated pure humic acid were recorded in the spectral range

of 4000 to 400 em -l in the nujol medium using an IR-spectro-

photometer (Nicolet FT-IR). The spectra obtained has been

shown in Fig.2-2. the observed bands and their assignment to

different functional groups have been shown in Table 2-8.

RESULTS AND DISCUSSION

The results obtained (Fig.2-2, Table 2-8) have

confirmed the presence of a number of functional groups in

the skeltal network of the humic acid. The notable functional

groups whose presence is confirmed in the humic acid

structure include hydroxy, aromatic, carboxylate, carbonyls

of aldehydes, ketones and quinones, and C=C unsaturated

groups, apart from stretching frequencies of N-H and S-H

groups.

The response of these groups towards different

reacting cationic species bas. been studied in detail, and

described in subsequent chapters.

2.5 BACTERIAL PRESENCE:STANDARD PLATE COUNT STUDY OF PADDY SOIL (KANHAR VARIETY).

INTRODUCTION

The Standard Plant Count ( Sl'C) procedure provides a

standardised method of determining the density of aerobic and

facultative aerobic and heterotropic bacteria in water a::.

l . = --n

J

0 .... '

as.s

80.9

53.0

L. 5.1

37.2

29.3

0 1700 1240 7 0

1.000 351.0 3060 2G20 2160 ( cm-1 l Wave number

Fig. 2-2 THE IR SPECTRA OF PURE HUMIC ACID.

Table 2-B THE PROMINENT IR BANDS -1

(em ) OF HUMIC ASSIGN/1ENT5. (REf.133, 134).

Wave numbers Band assiynments

3600 (B) J.J (0-H)

1740 (5) Charaacter is tic band of coo group .,.

1680 ( SJ Amide band 1

** 1550 (5) Thioamide band 1

1450 (11) Characteristic band of COOII group

1355 (N) Characteristic band of COOH grouo

*** 1030 (N) Thioamide band 11

680 ( II) Ar.lide band 11

IJ - broad, 5- strong, N- medium, W-weak;

• due to u (C=O)'

• • due 0 (11-11) <~~(c-ur • •,. due to JJ + v

(C-N) CC-5)"

ACID

G8

320

AND T/JL.i

69

well as in soil. Soil is a unique medium that contains a

diverse community of organisms representing many

morphological and physiological types. In attempting to

characterise these organisms, one has to take in to

consideration both their numbers and activities. Organisms in

soils are never static in number and activity. Therefore, the

enumeration of the population or microbial" activity

represents a point in time for that particular population

that is in dynamic equilibrium with its physical, chemical

and biological environments. Variation of microbial numbers

and activities can occur with depth and soil types (135,136).

Soil structure, texture and moisture levels can drastically

affect aeration within the soil environment attributing

aerobic to anaerobic properties. The season of the year is as

important as soil physical properties for the microbial

diversity ( 137). Hagedron ( 138) observid differences in

numbers and diversity of actinomycetes depending on soil

acidities. Schmidt (139) considers the plate count method

acceptable particularly because in this method media that are

specific for fixed physiological groups are developed, ana

the incubation conditions approach the natural environment.

It will have to be kept in mind that organisms are not

uniformaly distributed throughout the soil environment, but

rather are found in a point distribution depending on a

localised feature that allows maximum expression of that

particular organism.

70

MATERIALS AND METHODS

Sampling : The soil samples of the Kanhar type of paddy soil

was collected by standard procedure as described earlier

(Section 2.2). The samples were shifted to the laboratory

soon after collection. During the short period of storage of

the samples, a ro_om cooler was put on operation to provide a

static and moderately cool temperature.

Procedure : The freshly collected soil sample (1 g) was taken

in a sterilized bottle. 10 ml of aseptic distilled water was

added to obtain a suspension. The supernatant liquid was

decanted into another sterilized bottle and used for Standard

Plate Count study. Reagents required for the plate count were

prepared as follows :

Dilution water : (a) 3.4 g of patassium hydrogenphosphate was

dissolved in about 50 ml of distilled water. pH was adjusted

to 7.2 by using 1 N NaOH and finally the volume was made upto

100 ml by distilled water. (b) 3.8 g of magnesium chloride

was- dissolved in 100 ml of distilled water. 1.25 ml fo the

above stated phosphate buffer solution and 5.0 ml of

magnesium chloride solution were mixed in a volumatric flask

(1,000 ml) and the volume made upto 1 litre using distilled

water. After 15 to 20 min., this dilution water (1 L) was

sterilized in anautoclave.

Nutrient agar medium 5.0 g of trypton, 2.5 g of yea!;t

extract, 1.0 g of glucose and 15.0 g of agar were added to

71

1 litre of distilled water and sterilized in an autoclave.

Hethod Using the soil-extract solution, more diluted

samples were prepared using sterilized dilution water in

sterilized bott.les in the following ratios (i) 1:1, (ii) 1:10

(iii) 1:100, (iv) 1:1,000, (v) 1:10,000, (vi) 1:1,00,000. 1ml

aliquots of the above diluted samples were transferred

separately to sterilized Petri plates in three replicates. 12

ml of sterilized nutrient agar medium, 0 (temp.45 C) was poured

to each of these Petri plates. The medium and the samples

were mixed by gently moving the Petri plates in circular

order. When the medium was solidified, Petri plates were

inverted and incubated at 37° C for 48 hours in an incubator.

On completion of incubation period, bacterial colonies were

counted in each plate and calculated as No./ml by dividing it

with dilution factor ( 140). The average value was recorded

and shown in Table 2-9.

RESULTS AND DISCUSSION

The primary environmental variables influencing soil

bacteria include:moisture, aeration, temperature, organic

matter, acidity and inorganic nutrient supply. Some lesser

variables such as cultivation, season, and depth have also

been described to influence the denisty and composition of

the bacterial flora. The plate count of the .bacteria as found

here (Table 2-9) was 20 x 106

/g soil. The value of a typical

soil-profile in USA for a depth of 3-8 em i::, reported to be

7.8 x 106/g soil (39). The count found here thu::, indicated a

correct order.

72

* Table 2-9. THE PLATE COUNT AND THE ENVIRON11ENTAL CONDITIONS OF THE SOIL.

S.No. Environmental Parameters

1. Soil depth (em)

2. /1oisture (%)

3.

4 .

5.

6.

Oxygen level (ppm) ( 10% slurry)

Temperature ("c)

pH

Organic matter (%}

7. Inorganic nutrients (ppm)

8.

9.

Cu

Zn

Fe

Mn

Mo

Co

Season of soil collection

Plate counr found (/g)

Values found

2.0

5.3

79.0

23.5

7.2

6.4

63.0

55.0

1,10,000.0

682.0

2.5

16.0

Winter (11onth-January) (after harve·st)

20 X 106

* Parameters at S.No. 5-7 were determined described in Section 2.2 & 2.3.

earlier and

73

SUMMARY

This chapter wa.:... devoted to having a close

acquaintence with the soils of the local areas which formed

the central object for studying the impacts of the effluents.

For this purpose, the soil types, their morphological

features and their distributions in different districts of

the Chhattisgarh region were studied. Some importent terms

related to soil structure (bulk density, infiltration rate,

field capacity, wilting point) were also explained. The

importance of key-paramters (pH, electrical conductivity,

organic carbon, available nutrients, cation exchange

capacity, silica, iron oxide, aluminium oxide) which affects

the functionality of the soil was explained. The four

principal soil types (Bhata, Matasi, Dorsa, and Kanhar) were

collected from farm fields as per prescribed procedures and

their physico-chemical character is tics (pH, electrical

conductivity, organic carbon, available nutrients, cation

exchange capacity, exchangeable cations, 5102

, Fe2o

3, Al

2o

3J

were determined. A gradation amongst the four soil types used

here was found evident from the data obtained.While tpe Bhata

and Matasi type indicated weakly acidic to neutral nature,

the Dorsa and Kanhar types were neutral to slightly alkaline.

On the basis of available nutrients (N,K, P, CEC) and the

organic carbon, the Kanhar type appeared to be the most

fertile of the four types. It was found to be more useful to

select this particular soil type for the study of the

effluents' impacts.

74

The status of micronutrients (Zn, Cu, Mo, Co, Mn) and

micro-pollutants (As, Cd, Pb, Hg, Ni, Cr) were studied in

detail. The role of the micronutrients in the growth of the

plant species was studied. A literature survey to identify

the channel of entries of toxic metals from different

industrial sources and the resulting harmful effects on crops

and vagetations was carried out.

The humic acid contents of the paddy soil (Kanhar

type) were studied in detail. For this purpose, the genesis

and the structural aspects of the humic acid were studied and

described. The reactivity of the humic acid with metal ions

were also studied. For the experimental studies, the humic

acid was isolated form the paddy soil and purified with

standard procedures. The IR spectra of the pure humic acid

d d · f 4000 to 400 cm-l were recor e ~n the range o The bands

observed in the spectra were assigned to respective

functional troups. On the ·basis of the IR spectra, the

presence of -OH, -COO , amide, and thioamide groups were

indicated in the humic acid.

The bac·terial count in the Kanhar variety of paddy

soil was determined by the standard plate count method. Prior

to the plate count determination of the soil bacteria, the

environmental conditions of the soil (depth, moisture, oxygen

level, temp., pH, organic matter, inorganic nutrients, and

the season of soil collection) were also determined. The

plate count of the bacteria was found to be 20 x 10 6 /y soil.

The order of the count was found to be in agreement with that

reported elsewhere.

75

REFERENCES

1. Brady N.,"The Nature and Properties of Soils", (8th edn.) McMillan Publishing Co., Inc., New York (1978) 145.

2. Briggs D., "Soils", Nutterworth & Co.Ltd.,London (1977), 51-129.

3. Katre R.K., "Soils of Chhattisgarh Region", Indira Gandhi Krishi Vishwa Vidyalaya Report ( 1989).

4. Kanwar J.S., "Soil Fertility Theory and Practice", Indian Council of Agricultural Research, New Delhi (1976).

5. Bear F.E.,"Chemistry of the Soil",(2nd edn,),Oxford & IBH Publishing Co, New Delhi (1964), 78-160.

6. Swindale L.D. and M.L.jackson, Trans International Society of Soil Science, 6th Congress, Paris 5, ( 1956), 233-239.

7. Daniels R.B., G.H.Simonson and R.L.Handy, Soil Science, 91 ( 1961)' 378-382.

B. Schwertmann U., Neues Jb Miner., 93 (1959), 67-86.

9. Soileau J.M., and R.J.Cracken, "Agronomy Abstract", American Society of Agronomy; Madison, (1962).

10. Jackson M.l., "Soil Chemical Analysis", Prentice Hall of Indian Pvt. Ltd., New Delhi (1967).

11. Loveday J., "Methods for Analysis of Irrigated Soils", Commonwealth Agricult~ral Bureaux,Clayto~. (1974).

12. Page A.L., (Ed.), "Method of Soil Analysis", Sail Science Society of America Inc., Madison,

(Part II) (1982).

13. Bassett J., R.C.Denney, G.H. Jeffery, J. Mendham, "Text Book of Quantitative Inorganic Analysis, (4th edn.), ELBS and Langman, Essex, (1989) ·.

14. Snell F.D. Analysis'1

,

(1959).

and C.T. Snell, (Val.II A), D.Van

"Colorimetric Nostrand Co.,

11ethods of New Jersey,

15. Das A.K., "A Text Inorganic Chemistry", Delhi ( 1990).

Book CBS

on Medical Publishers

Aspects of Bio­& Distributors,

16. Tisdale L.S., N.L.Werner, "Soil Fertility and Fertilizers'" The 11cMillan Company, New York, (1956).

17. Bromfield S.M., V.B.D.Skirman, "Biological Oxidation of Manganese in Soil", Soil Science, 69, (1950), 337-348.

76

18. McLaren A.D. and Edward Arnold Ltd., York, (1967).

G.H.Peterson, "Soil Biochemistry", London, and Marcel Dekker Inc •• New

19. Agrawal R.R ..• "Soil Fertility in India", Asia PUblishing House, New Delhi, ( 1967).

20. Sopher C. D., "Soils Publishing Company Inc.,

and Soil Virginia,

Management", (1978).

Reston

21. Webley D.M. and Duff R.B •• Plant and Soil, 22, 307 (1978)

22. Hunter J.G. and O.Vergano, Ann.Appl.Biol., 39, 279, ( 1952).

23. Kanwar J.S. and N.S. Randhawa, Micronutrient Research in Soils and Plants in India :A Review, ( 1967).

24. Taylor R.N., R.M., McKenzie and K.Norrish, Aust.J.Soil Research, 4, 29, (1966).

25. Chatt J •• Proc.Roy.Soc., 172 B, 327 (1969).

26. Delwiche c.c. and C.M.Johnson, Plant Physiology, 36, 73, (1961).

27. Ozanne P.G., E.A.N., Greenwood and T.C.Shaw.,Aust.J.Agric Res., 14, 39, (1964).

28. Jones L.H.P., J.Soil Sci., 8, 313 (1957).

29. Trobisch S. and G.Schilling, Chem.el Erde., 23, 91, (1963)

30. Dautil P., Comp.Rend.Acad.Agric., 947, (1967)

31. Swaine D.J., Commonw.Bur.Soil Sci.Tech.Communs., (1953).

32. Russell E.W., "Soil and Longman, Essex,

Conditions -(1973).

and Plant Growth"~

48,

ELBS

33. Booz Allen Applied Research. Inc •• A Waste Materials, Hazardous Effects and (vol.II}, Report PB-221, 446, Va.Nat. Service, Springfield.

Study of Hazardous Disposal Methods, Tech. Information

34. Gupta S.K. and V.Chenk, "Arsenic Removal by Adsorption". J.Water Pollution Control Federation, (1978), 493.

35. Frost D.V., "Arsenic:Science or Superstition". Food and Nutrition News, (1968).

36. Crafts Control (1933),

A.S., "The Use of Deep Rooted

461-498.

of Arsenical compounds in the Perennial Weeds", 1/ilgardia, 9

37. Crafts A.S., "The Acid Arsenical Method in Weed Control··. J.Amer.Soc.Agron •• 29 (1937), 934-943.

77

38. Ashton F.M. and A.S.Crafts, John Wiley & Sons, New York,

"Mode of Action of Herbicides", (1973).

39. Alexander M., Eastern Ltd.,

"Introduction to Soil Microbiology", New Delhi, ( 1978).

Wiley

40. Woolson E.A. and P.C.Kerarney, Environ.Sc.Technol., 7, ( 1973). 47-50.

41. McBride B.C. and R.S.Wolfe, Biochemistry, 10, (1971), 4312-4317.

42. Shukla S.S. and H.V.Leland, J.Water Pollut.Control Fed., 45 (1973), 1319.

43. Lazms A.L., E. Lorange and J.P.Lodge, Environ.Sci.Technol 4, ( 1970). 50.

44. Matsunaga S., M.Kohno, K.Nagai, T.Nakayama and H.Ohide, Arch.Kohno.Clin., Med.Res.Inst., 1, (1962), 1.

45. Kohno M., H.Sugihara, T.Nakayama and N.Hagino, Clin. Nutr 9, (2}, I, (1956).

46. Lead, National Academy of Science, ANON, Washington, D.C. (1972).

47. Mahaggey K.R. and P.E.Liussen, Environ.Health Perspect., 12, (1975), 63.

48. Darn C.R.,J.O.Pierce,G.R.Chase and P.E.Phillips, Environ. Res., 9, (1975), 159.

49. Lisk D.J., A.K.Furr, D.R.Merten,W.H.Gutemann and C.A. Bache, J.Agr.Food Chern., 22 (1974), 954.

50. Irwin J.C.and L.H.Karstad, J.Wildl.Dis., 8, (1972). 149.

51. Muller P.K. adn R.L.Staneiy, "Origin of Lead in Surface Vegetation", ATHL Report No.87, State of California, Department of Public Health, Air and Industrial Hygiene Laboratory, Berkeley (1970).

52. Hammond P.B. and A.L.Aronson, "Lead Poisoning in Cattle and Horsesin the Vicinity of a Smelter", Ann.N.Y.Acad.Sci 111, (1964), 595-611.

53. Shacklette H.T., J.C.Iiamilton, J.G.Boerengen and J./1.Bowes. ''Analyses of Plants Collected Throughout the Conterminous United States at. Intervals of about 50 miles, in connection with the Soil Study", U.S.Geol.Survey Prof. Paper 574-D, (1971).

54. Connor J,J., 1/.T.Shacklette, and J.A.Erdmann,U.S. Gcol. Sruvey Prot. Paper 750-B, ( 1971).

55. Shack e 1 e t t e II. T. , Connor J. J. , U. S • G eo 1. S u v e y pro f. )'a i· c r • 574-E, (1960).

78

56. Haupt H.J., F.Hurber,J.Gmehling, "Zerset Zungs-reaktion von Dimethylbleichlorid in Losungen mit undohne Fremdsal­zzusatz", Z.Anorg.Allg.Chem., (1972), 390.

57. Schroeder H.A., "The Poison Around Us", Indiana

58.

University Press, Bloomington (1974).

Buck W.B.,G.D.Osweiler and G.A.van Diagnostic Veterinary Toxicology", Hunt, Dubuque, Iowa (1973).

Gelder, "Clinical and (Ist edn.). Kendall/

59. Dewey J.F. and R.F. Pendleton, Agrichemical Age, 14, (4), ( 1971).

60 Selikoff I.J., Environ.Res:, 4 (1971)

61. Schacklette H.T., U.S.Geol.Survey Prof.Paper 713, (1970)

62. Berlin M. and S.Gibson, Arch.Environ.Health, 6, (1963), 61 7.

63. Rothstein A. and A.D.Hayes, J.Pharmacol.Exp.Ther., 130, (1960). 166.

64. Jensen S. and Jernelow, "Biological Methylation of Mercury in Aquatic Organisms", Nature, 233, (1969), 753.

65. Vallee Mercury, 91.

B.L. and Cadmium,

D.D. Ulmer, "Biochemical Effects of and Lead, Ann. Rev.Biochem., 41, (1972)

66. Yuhuan Lin, K.Demeng and L.Cbing, I., "Species Distribu­tion of Mercury in Ji Yun River Sediments", Huanjing Huaxue, 2, ( 1980) 10.

67. Jawald M., F.Ingman, Extraction Studies on Methylmercury (II) and Ions", Acta Chem.Scand.,

D.H.Liem and T.Wallin, tbe Complex Formation Bromide, Chloride, and A 32, (1978), 7.

"Solvent Between Nitrate

68. Wallace,R.A., W.Fulkorson, W.D.Shults and W.S. "Mercury {n the Environment-The Human Element" Oak National Laboratory Report, NSF-EP-1, National Infor.Serv., Springfield, Virginia, (1971).

Lyon, Ridge Tech.

69. "/>lercury and the Environment", OECD Publn., Paris, (1974)

70. Pang.S.W.,O.K.Qui and J.F.Sun,"Sequential Chemical Extraction for Speciation of Mercury in River", /lanjing Kexue Xeubao, 1, ( 1981), 234.

71. Xu K. and A.Peng, "Computation of Mercury Species in Downstream J Yun River", /luanjing lluaxue, 3 (1984), 19.

72. Reimers R.S. and P.A.Krenkel, "Kinetics Adsorption and Desorption in Sediments", Control Fed., 46, (1974), 352.

of /·Jercury J.Water Poll.

79

73. Li.C.S. and C. I. Liu, "Adsorption of Mercury in Fresh Water", Huanjing Huaxue, 1, ( 1982) 1 304.

74. Peng A., W.H. Wang, Humic Acid from Ji (1981), 126.

"Extraction and Characterisation Yun River", Huanjing Kexue Xuebao.,

of 1,

75. Wang S.H.,T.C.Hao, And G.O.Liu, "Release Rate of Methyl mercury form River Sediment", Huanjing Kexue, 2, ( 1978), 11.

76. Page A.L. and Bingham F.T., Residue Reviews, 48, (1973),

"Cadmium in 1-44.

the Environment",

77. Waketa H. and R.A. Schmitt, Wedepohl,

"Cadium K.H.),

in Hand Book of Springor Verlag,

78.

79.

Geochemistry, (Ed. Berlin, (1970).

Oehme F.W.,"Toxicology Environment", (Part I), (1978).

of the Marcel

heavy Dekker

Metal in the Inc., New York,

Thornton I. and A .£.Marples, "The Distance Derived from Geochemical and Industrial Agricultural Soils and Pasture Herbage in Britain", Proceedings the Second International of Cadmium in the Environment, Cannes, ( 1979).

of Cadmium Sources in

Parts of Conference

80. Williams C.H. and D.J.David, "The Accumulation in the Soil of Cadmium, Residues from Phosphate Fertilizers and Their Effects on the Cadmium Contents of Plants", Soil Sci., 121, (1976), 86-93.

81. "Cadmium in the Environment", IRCC Publn., London, ( 1973)

82. Thornton !.,"Background Levels of Heavy and Plants, Proceedings Conference on Contaminated Land", Eastbourne, ( 1979).

t1etals in Soils Reclamation of

83. Jarvis S.c., L.Jones and M.J.Hopper, "Cadmium uptake from Solution and Its Transport from Roots to Shoots", Plant and Soil, 44, ( 1976), 179-191.

84. John M.K., "Cadmium uptake Influenced by Various Environmental Pollution, 4,

by Eight Soil Level (1973), 7-15.

Food of

Crops as Cadmium",

85. Stenstrom T. and H.Lonsjo, "Cadmium Availability to Wheat: A Study with Radioactive Tracers Under Field Conditions'', Ambia., 3, (1974), 87-90.

86. Backett P.H.T. Toxic Elements 95-106.

and R.D. Davis, "Upper Critical Levels of in Plants", New Phytologist. 79, (1977),

87. Davis R.D., P.H.T.Backett and E.Wollen,"Critical Le1•els of Twenty Potentially Toxic Elements in Youn~ Sprin~ Barley", Plant and Soil, 49, (1978), 395-408.

80

88. Boggess S.F., S.Willavize and Koeppe D.E., "Differential Response of Soya bean varieties of Soil Cadmium", Agronomy Journal, 70 ( 1978), 756-760.

89. Hubbard A. W. and D.G.Lindsay, "Dietary Intake of Heavy Metals by Consumers in the U.K., Proceedings Con f. on Management and Control of Heavy Metals in the Environment", Edinburgh, (1979).

90. WHO Publn.,"Evaluation of Certain Food Additives and the Contaminants Mercury, Lead and Cadmium", WHO Technical Report Series no.505, WHO Geneva, (1972).

91. "Critria of Facility and 44, ( 1979).

Classification Practices", EPA

of Solid Waste Disposal Publn., Federal Register,

92. Tsuchiya K., "Causation of Ouch-ouch Disease", An of Medicine, 18, (1969), 181. Inroductory Review, Keio J.

93. Tsuchiya K., "Cadmium Studies in Japan:A Review", £levier North Holland Biomedical press, Amsterdam, ( 1978).

94. Kazantzis G., F.Flynn, J.Spowage and G.Troh, Tubular Malfunction and Pulmonary Emphysema in Pigment Workers", Quarterly J. of Medicine, 32, 165-192.

"Renal Cadmium (1963),

95. Lauwerys R.R., J.P.Buchet, H.A.Roels, J.Brouwerys and D.Stanescu, "Epidimiological Survey of Workers Exposed to Cadmium", Archives of Environment Health, 18, (1974), 145-148.

96. Kauanaugh K. and D.F.Evans, ~Raman and Infrared Spectra of Methyl Cadmium Halidesand Related Compounds, J.Chem.Soc. (A), (1969), 2890.

97. Robinson J.W. and E.L. Kiesel, "Methylation of Cadmium with Vitamin B:A Possible Method of Detoxification", J.Environ.Sci.Health, (A). 16, (1981). 341.

98. Tang H.X., H.B., Xue, "Adsorption Characteristics of Cadmium Pollutants on Chines<; Clay Minerals", Huanjing Kexue Xuebao, 1, (1981), 140.

99. Tang H.X. and H.B.Xue, "Study on f1ulticomponent Adsorption Model fo Aquatic Sediments with a Sequential Chemical Separation Procedure", Huanjing Kexue Xuebao, 2, (1982), 292.

100. Turner M.A., "Effect of Cadmium Treatment on Cadmium and Zinc uptake by Selected Vegetable Species", J.Environ. Qual., 2, ( 1973), 118.

101. Fukushima M., A. Ishizaki, f1.Sakamoto and J.Kobayashi, Jap.J.IIyg., 28 (1973), 406.

102.

103.

104.

105.

106.

107

108.

109.

110.

111.

112.

113.

114.

115.

116.

117.

118.

11 9.

Fukushima M., "New Methods in Environmental Chemistry and Toxicology", Proceedings International Symposium on Ecological Chemistry, Susono, {Nov., 1973).

Kobayashi J. and s Muramoto, Jap.J.Hyg., 24 (1969), 66, 26, (1971), 170.

Hagiono N., J.Kobayashi, Jap.J.Hyg., 23, {1968), 196

Christian G.D., E.C.Knoblock,W.L.Purdy and W.Mertz, Biochem.Biophys.Acta, 66, 91963), 420.

Donaldson R.M.and R.F.Barrearas, J.Lab.Clin.Med., 68 91966), 484.

Gray S.J. and K.Sterling,J.Clin.Invest,29 (1950), 1604

S c h c k 1 e t t e H. T. ; H. I. Sauer and A . T. M i c s·c h, U. S. G eo 1. Survey Prof.Paper 574-C, 1970, 39.

McMurtrey j.D. and W.O.Robinson, "Year Book of Agriculture", U.S.Dept.Agr., (1938), 807-829.

"Chromium", NAS Publn.Washington,D.C., (1974).

Mertz W., "The Essential Trace Elements", Science, 213 (1981), 1332.

Kent N.L. and R .A .McChance, Biochem. J. ' 35, (1941), 877.

Kent N. L. and R.A.McChance, Biochem. J.' 35 {1941) 837.

Schroeder H.A. and J.J.Balassa, J.Chronic Dis., 15, (1961), 51.

Bertrand G. and M.Macheboeuf. C.R.Acad. Sci., . 180, {1925), 1380.

Bertrand G. and M.Macheboeuf, C.R.Acad.Sci., 180 {1925), 1993. Bertrand G. and M.Macheboeuf. C.R.Acad.Sci., 182 {1926), 1504.

Eichhorn G.L., Nature, 194, {1962), 474.

81

Connor J.J. Paper 574-F,

and JJ.T. Shacklette, {1975). 168.

U.S.Geol.Survey Prof

120 Erdman J.A .. II.A. Shacklette and J.R.Keith,U.S.Geol. Survey Prof. Paper 954-C, { 1976), 87.

121.

122.

123.

124.

125.

126.

12 7.

128.

129.

130.

82

Fuge R. and K.H.James, "Trace Metal Concentrations in Brown Seaweeds, Cardigan Bag, Wales", Har.Chem., 1, ( 1973). 281.

Richard J., B.Thompson, H.George, P.Lazzy, "Analysis of Selected Elements in Atmospheric Particulate Hatter by Atomic Absorption", Atomic Absorp. News Letter, 9 (3), (1970).

Varian Publn., "Analytical Method of Flame Spectroscopy" Varian Publication No.85-100009-00, Springwale, (June, 1978).

Van Loon J:c •• "Analytical scopy Selected Methods", ( 1980). 60-70.

Atomic Absorption Spectra­Academic Press New York,

APHA-AWWA-WPCF, "Standard Methods for the Examination of Water and Waste Water", (14th edn.), American Public Health Association, Washington, D.C., (1976).

Parsons J.W. and J.Tinsley,Soil Sci., 92 (1961), 46.

Mehta N.C., P.Dubach and H.Deuel, Z.Pfl.Ernahr., 102 ( 1963). 128.

Laren Me. and G.H.Peterson (ed.). "Soil Biochemistry", Marcel Dekker Inc •• New York, ( 1966).

Gieseking J.E., (ed.), "Soil Organic Components", (Vol.1), Springer-Vorlag Inc., New York (1975)

Theng B.K.G. Bumic Acids",

and J. R. H. Wake. "Infrared Spec truro Soil Sci., 102, (1966), 70-72.

of

131 Prasad B. and M.K.Sinha, "Properties of Poultry litter Humic Acid Fractions and Their metal Complexes", Plant and Soil, 63, (1981), 439-448.

132.

133.

134.

135.

136.

Grace D., B.Khar, B.Prasad, M.K.Sinha and S.B. Pandey, "Interaction of Metal Ions with Fulvic and Humic Acids Isolated from· Forest and Cultivated Soils of Meghalaya Sti!te, Ind.J.Forestry. 8, (3) (1985). 213-2J9.

Suzuki I., Bull.Chem.Soc.Japan, 35, (1962). 1286.

Rao C.N.R., "Chemical Spectroscopy", Academic

Applications of Infrared Press, New York & Longan,

(1963), 260-263.

Hishutsin E.N., "The Law of Zonality and the Microbial Association of the Soil", 19, (1956), 333-392.

the Study of Soils Fert .•

Stare A., "Hikrobiologischc Untersuchungen Einigcr Podsoliger Boden Kroaticns", Arch.Hikrobiol.. 1:. (1942), 329-352.

13 7.

138.

139.

14 0.

Lochhead A.G. and F.E. Chase, "Qualitative Studies of Soil Micro-organisms, V.Nutritional Requirements of the Predominant Bacterial Flora", Soil Sci.,55, (1943) 18S-19S.

Hagedron c., "Influence on Soil Acidity on Streptomyces Populations Inhibiting Forest Soils", Appl.Environ. Microbial., 32, (1976), 368-375.

Schmidt E.L., Among Modern 4S1-4S4.

"The Traditional Plate Count Method:Chairman's Summary",

Technique (1973),

Saxena M.M., "Environmental Analysis, Water, Soil and Air, Agro Botanical Publishers, India, Bikaner, ( 1978)

83