Adsorption of Poultry Litter Extracts by Soil and Clay

Kim H. Tan,* Vaman G. Mudgal, and Ralph A. Leonard Department of Agronomy, Universi ty of Georgia, and U S D A , Watkinsville, Ga.

Adsorption of the water-soluble fraction of poultry lit- ter was investigated at constant temperatures using Cecil, Tifton, and Hayesville soils and kaolinite and bentonite as adsorbents. Organic matter extracts were characterized by infrared spectroscopy. The results indicated that broiler litter was adsorbed in almost similar amounts as layer lit- ter extract by either soils or clays. However, degree of ad- sorption varied with types of clays as well as with soil se- ries. The slope of the adsorption isotherms was steeper for bentonite than for kaolinite. For soils, the slope of the iso- therms decreased in the following order: Hayesville > Tif- ton > Cecil. The adsorption isotherms were linear within the concentrations ,examined; the slopes decreased with increasing temperature from 25, 35 to 50°C. Protonated poultry litter extract was adsorbed in larger amounts than Naf -saturated extract, indicating that ionic bonding might be involved, or that ionization of carboxyl groups was reduced.

The application of organic matter as a soil amendment currently receives considerable research attention due to the ever-expanding production of organic waste and the resultant sanitary disposal problem. Poultry litter is of special concern in the southeastern part of the United States. Eleven million tons are produced each year in the Southeast ( I ) and, if not properly disposed, may consti- tute a pollution hazard.

Investigations have shown that the manure and litter from broiler and layer houses could be a valuable source of plant nutrients (2, 3 ) . Significant yield responses re- sulting from the use of poultry litter have been reported for corn, millet, potatoes, cotton, oats, vegetables, and forage crops (3-5). However, heavy applications of poultry litter to the same field each year could also prove waste- ful, with respect to some plant nutrients, in addition to creating hazards of grass tetany and fat necrosis in cattle and environmental pollution. The problems of pollution and plant nutrient losses resulting from the use of poultry litter depend to some extent on the rate of litter decompo- sition and mobility of soluble components in the soil.

Since little is known regarding adsorption and leaching of poultry litter components in soils, this study was ini- tiated to investigate adsorption of different types of poul- try litter by soils.

Materials and Me thods Poultry Litter. Litter selected for this investigation was

from broiler and layer poultry. Poultry litter (broiler and layer) consisted of accumulated droppings, pine wood shavings, feathers, and wasted feed. Each poultry litter (fresh) was freeze-dried, ground, and separately extracted with distilled water according to the following procedures.

A sample of 100 grams of poultry litter was added to 1000 ml of boiling water, cooled overnight, and centri- fuged to remove suspended particulate matter. This method dissolved 16% of the broiler litter and 13% of the layer litter ( I ) . The soluble extracts were then freeze- dried and stored for later use and analysis. Part of the ex-

tracts were saturated either with H+ or Na- by shaking with H + - or Na+-saturated Dowex 50W-X8 cation ex- changer (20-50 mesh). The H + - and Na+-saturated organ- ic matter extracts were recovered by centrifugation a t 15,000 rpm, freeze-dried and stored for use in the adsorp- tion experiments. The organic material was not adsorbed by Dowex 50W-X8 and was anionic in nature. Therefore, it was acting as a cation exchanger.

Total elemental analysis of the original litter and its ex- tracts was performed by direct-reading emission spectro- graphic techniques. One gram of freeze-dried sample was ashed a t 450°C in a muffle furnace and the ash was taken up in a buffer solution for burning in a carbon arc to de- termine macro- and microelement content. For further details, reference is made to Jones and Warver (6). Nitro- gen was analyzed separately by the semimicro Kjeldahl method ( 7 ) .

Soils. Soils used for the experiments were (a) Cecil sur- face soil (0-15 cm) and Cecil subsoil (15-46 cm), (b) Tif- ton A2 (5-25 cm) and B l t (25-46 cm), and (c) Hayesville B21t (51-71 cm) samples. According to the U S . Soil Tax- onomy, these soils are classified as Typic Hapludults, Plinthic Paleudults. and Typic Hapludults, respectively (8). These soils were selected to represent large areas of (a) the Piedmont, (b) the Coastal Plain, and (c) the Mountain region of the Southeast. The samples were air- dried and sieved to pass a 2-mm sieve before use. In addi- tion, pure kaolinite and bentonite (purchased from Ward’s Natural Science Establishment, Inc.) were used for the adsorption experiments.

Adsorption Analysis. To 10 grams (oven-dry basis) of soils (or 1 gram of kaolinite or bentonite, <2p) in 250-ml Erlenmeyer flasks were added 0, 0.25, 0.50, 1.00, and 3.00 grams of freeze-dried organic matter extract and 25 ml of distilled water. The mixture was shaken for 5 hr and al- lowed to stand overnight at a constant temperature of 35°C. The supernatant was separated by centrifugation a t a speed of 15,000 rpm using the Sorvall Superspeed RC-2B centrifuge with which the temperature could be controlled a t 35 + 1°C. The supernatant was then collect- ed, freeze-dried, and weighed. The difference between amount of poultry extract added and recovered in the su- pernatant was used as an estimate of amount of organic matter adsorbed by soil or pure clay. The same adsorption experiment was also carried out at 25 and 50°C and with H A - and Na+ -saturated organic matter extracts, respec- tively, in four replications.

Infrared Analysis. Characterization of organic matter extracts collected before and after adsorption with clay or soil was conducted by infrared spectroscopy, using the micro-KBr pellet technique and a Beckman IR-18A spec- trophotometer ( I , 9, I O ) .

Results and Discussion Elemental Composition. Elemental composition of

poultry litter samples used in this study is given in Table I. Values reported are in terms of amounts that were water soluble as determined by analysis of the extract and amounts remaining insoluble as calculated by difference. The dominant inorganic cation in the water extract was K T . The dominant anion is probably C1-. On a weight basis, soluble KC1 and other inorganic salts amounted to

132 Envi ronmenta l Sc ience & Technology

Table 1. Poultry Litter Composition Macro Elements, %

N P K Ca Mg N a

sol lnsol sol lnsol sol lnsol sol lnsol Sol lnsol sol lnsol

Broiler litter 1.55 2.18 0.25 1.46 1.61 0.00 0.02 1.29 0.09 0.24 0.03 0.17 Layer litter 0.90 1.90 0.10 1.45 1.69 1.20 0.01 2.99 0.04 0.77 - -

Micro Elements, ppm

Mn Fe B c u Z n A I Mo

Sol lnsol Sol lnsol Sol lnsol Sol lnsol Sol lnsol Sol lnsol Sol lnsol

Broiler litter 5 333 16 984 16 15 16 23 18 209 10 1710 1 5 Layer litter 2 326 58 942 23 17 35 26 7 292 6 1674 1 8

2&25% of both extracts. This should be kept in mind when interpreting results from the adsorption experi- ments.

Results of gel filtration, which will be reported in more detail in a later manuscript, indicated that the organic material in the extracts was composed of compounds in the 1500-30,000-molecular-weight range. Two distinct but overlapping molecular weight classes were evident.

Adsorption by Clays and Soils. Isotherms for adsorp- tion of the poultry litter extracts on clays and soils are shown in Figures 1-4. In general, the isotherms were lin- ear with concentration; therefore, calculated linear regres- sion lines were drawn through the points. Calculated equations for each line are also given. This straight-line relationship in organic matter adsorption is in agreement with results as reported by Weber (11) and Greenland and Oades (12). According to the latter authors, adsorption of organic matter by soils conforms to the Langmuir equa- tion, in contrast to the opinions of Bailey et al. ( 1 3 ) and Inoue and Wada (14), who stated that adsorption of or- ganic matter by soils should follow the Freundlich equa- tion. In the present results it is apparent that adsorption obeyed the Langmuir equation owing to the presence of a perfect linear regression. Plotting the respective data on semilog or log-log graph paper yielded a curved line, indi- cating that the Freundlich equation, X l m = KC1 n, was not obeyed. The observation for adsorption, according to the Langmuir model, was compatible with the fact that soil and clay did not exhibit an infinite capacity to ad- sorb, but would sooner or later be saturated.

The isotherms also indicated that extracts of broiler and layer litter were adsorbed equally by kaolinite (Figure 1, Nos. 3 and 4 ) . The slope of isotherms 1 and 2 (Figure 1) was nonsignificantly different, suggesting that broiler (Figure 1, No. 1) and layer litters (Figure 1, No. 2) were adsorbed in similar amounts by bentonite. However, the position of isotherms 1 and 2, above isotherms 3 and 4, re- vealed that bentonite adsorbed more poultry litter extract than kaolinite.

The adsorption of both the litter extracts varied, de- pending on soil series and location in the soil profile (Fig- ure 2). Within a series, the surface soil, higher in organic matter but lower in clay content, had a higher adsorptive capacity than the subsoil. For subsoil material, the mag- nitude of adsorption in decreasing order was Hayesville > Tifton > Cecil. The isotherms in Figure 3 for adsorption of broiler litter on Cecil topsoil a t 25", 35", and 50°C show that adsorption decreased with increasing temperature. No measurements were made as to the exo- or endother- mic nature of the adsorption process, since analyses were done at constant temperatures.

( I ) Y = 0 . 4 5 X - 0.06 r : 1.0'"

(2) Y = O . 3 9 X - O . O 3

r: I.o**

(3 ) Y=O.23X-O.O12 r : 1.0" ' r = 0.39'"

(overage of 4rsps)

( 4 ) Y = 0 . 2 5 X - 0.06

I n

I I .o 2.0 EQUILIBRIUM CONCENTRATION (0)

Figure 1. Adsorption of water extracts of poultry litter at 35°C by clays (significant at the 1% level of probability) ( 1 ) Broiler litter by bentonite, (2 ) layer litter by bentonite, (3) layer litter by Kaolinite, and (4 ) broiler litter by kaolinite

The isotherms in Figure 4, contrasted adsorption of Na+ - and "-saturated extracts by Cecil topsoil and Cecil subsoil. In each soil horizon, adsorption was greatest for the H + -saturated extract. Protonated organic com- pounds are generally considered more reactive with clay surfaces than nonprotonated compounds ( I , 13, 1 5 ) . Pro- tonation of weak base functional groups such as -HN2+ might produce positive electrical charges that would bind tightly to the negative clay surface, a process which might be active in present experiments. Another possibility was that neutralization of carboxylic acid groups would also increase adsorption by reducing the negatively charged groups on the molecule which would be repelled by the negative clay surface.

The effect of Na- or H+ treatment on adsorption was greater in the subsoil system than in the topsoil. Again, this difference might be a reflection of the presence of higher native organic matter in the topsoil.

Infrared Analysis. Poultry litter extracts undoubtedly contained a range of compomds. Infrared spectra (Figure 5) of the freeze-dried extract were characterized by weak

Volume 9, Number 2 , February 1975 133

bands at 2920 cm-1 and strong bands at 1620 and 1400 cm-1 for aliphatic C-H and carboxyl stretching vibra- tions, respectively. Strong, unassignable bands were also present in the 1130-1050 cm-1 region. These band charac- teristics and general spectral features corresponded closely to those reported earlier for polysaccharides (16, 17). Al- though the extracts contained nitrogenous compounds (Table I) and other substances, apparently the dominant compound was polysaccharidelike material originating

0.9 Y 1.21 X - 0.43

( I ) r = I . O * * i 0 I 1 , ,

0.71 /

Y * 0.33X $605 I 1 = o . d ?

average of 4 reps.

1.0 2.0 EQUILIBRIUM CONCENTRATION (91

0

probably as a microbial decomposition product of the wood shavings, feed residues, or both.

Infrared spectra (Figure 5 ) of material remaining in so- lution after contact with soil were similar to those of the original material. However, for both broiler litter and layer litter extracts, the carboxyl vibration at 1400 cm-1 was reduced by contact with soil. This observation sug- gested that compounds with more reactive carboxyl groups are preferentially adsorbing.

0.6 '

(avarape of 4 reps.)

"0.2

0 0.5 1.0 2.0 EQUILIBRIUM CONCENTRATION (9)

Figure 4. Adsorption of H + - and Na+-saturated broiler extracts by Cecil soil (significant at the 1% level probability) (1) H+-saturated extract by Cecil subsoil, (2 ) H+-saturated extract by Cecil topsoil, (3) Na+-saturated extract by Cecil topsoil, and (4 ) Na+- saturated extract by Cecil subsoil

Figure 2. Adsorption of water extracts of broiler litter at 35°C by soils (significant at the 1 % level of probability) ( 1 ) Tifton A2, (2 ) Hayesville B211, (3) Tifton B l t , and (4) Cecil subsoil

/ Y = 0.39X-0.09

r = I,o**

Figure 3. Adsorption of water extracts of broiler litter by Cecil topsoil at (1) 25°C (2) 35"C, and (3) 50°C

I I 4000 2000 1600 1000

wavenumber (cm-I) Figure 5. Infrared spectrograms of water extracts of poultry lit- ter before and after adsorption by Cecil topsoil (1) Layer litter extract after adsorption, (2) layer litter extract before ad- sorption, (3) broiler litter extract after adsorption, and (4 ) broiler litter extract before adsorption.

134 Environmental Science 8, Technology

Literature Cited

(1) Tan, K. H., Leonard, R. A., Bertrand, A. R., Wilkinson, S. R., Soil Sei. Soc. Amer. Proc., 35,265-9 (1971).

(2) Lassiter, J. W., Mason, J. V., Perkins, H. F., Brown, A. R., Beaty, E. R., Univ. Ga. College Agr., Ga. Agr. Expt. Sta., Res. Bull., 25,23 pp, 1967.

(3) Perkins, H. F., Parker, M. B., Walker, M. L., ibid., Bull. N.S., 123,24 pp, 1964.

(4) Papanos, S., Brown, B. A., Storrs Agr. Expt. Sta., Univ. Con- necticut, INF Series 13, 1-5, 1950.

(5) Parker, M. B., Univ. Ga., College Agr., Ga. Agr. Expt. Sta.,

(6) Jones, J. B., Jr., Warver, M. H., “Analysis of Plant Ash Solu- tion by Spark Emission Spectroscopy,” in E. L. Grove and A. J. Perkins, Eds., “Development in Applied Spectroscopy,” Vol. 7A, pp 152-60, Plenum Press, New York, N.Y., 1969.

(7) Bremner, J. M., “Total Nitrogen,” in C. A. Black (Editor-in- Chief), “Methods of Soil Analysis,” Part 2, A.S.A. Monograph

(8) Soil Survey Staff, “Soil Series of the United States, Puerto Rico, and the Virgin Islands, Their Taxonomic Classification,” 361 pp, Soil Conservation Service, USDA, 1973.

(9) Tan, K . H., McCreery, R. A., Soil Sei. Plant Anal., 1, 75-84 (1970).

Bull. N.S., 159,5-15, 1966.

9, 1149-78, 1965.

(10) Tan, K . H., King, L. D., Morris, H. D., Soil Sei. Soc. Amer. Proc., 35,718-51 (1971).

(11) Weber, J. B.,Amer. Mineralog., 51,1657 (1966). (12) Greenland, D. J., Oades, J . M., Trans., 9th Intern. Congr.

(13) Bailey, G. W., White, J. L., Rothberg, T., Soil Sci. SOC. Soil Sci. I, pp 657-78, 1968.

Amer. Proc., 32,222-34 (1968). (14) Inoue, T., Wada, K., Trans., 9th Intern. Congr. Soil Sci. 111,

(15) Mortland, M. M..Adv. Aeronomv. 22.75-117 (19701. pp 289-98, 1968.

(16) Mortenson, J . L., Anderson, D.” M.,’ White, J . L.; “Infrared Spectroscopy,” in C. A. Black (Editor-in-Chief), “Methods of Soil Analysis,” Part 1, A.S.A. Monograph 9,743-70, 1965.

(17) Tan, K. H., Clark, F. E., Geoderma, 2,245-55 (1969).

Received for review April 19, 1974. Accepted Oct 15, 1974. Contri- bution from the University of Georgia, Agricultural Experim‘ent Station, College Station, Athens, Ga., and Soil, Water and Air Sciences, Southern Regional Agricultural Research Service, U.S. Department of Agriculture. Mention of commercial products is for identification only and does not constitute endorsement by any agency of the U.S. Government.

Rates of Degradation of Malathion by Bacteria Isolated from Aquatic System

Doris F. Paris,* David L. Lewis, and N. Lee Wolfe

Freshwater Ecosystems Branch, Southeast Environmental Research Laboratory, National Environmental Research Center-Corvallis, U . S . Environmental Protection Agency, Athens, Ga. 30601

A heterogeneous bacterial population that grew in cul- ture solution with 0,O-dimethyl S-( 1,2 dicarbethoxy)- ethylphosphorodithioate (malathion) as the only extrane- ous source of carbon has been isolated. Gas-liquid chro- matographic analysis of methylated samples from the cul- tures showed that the major metabolite was @-malathion monoacid. Only 1% of the malathion was transformed to malathion dicarboxylic acid, 0,O-dimethyl phosphorodi- thioic acid, and diethyl maleate. At low concentrations of malathion (less than the value of K,) and low concentra- tions of bacteria, the rate of bacterial degradation can be described mathematically by a second order rate expres- sion. System analysts may find this kinetic expression useful in the construction of models.

0,O-dimethyl S- ( 1,2 dicarbethoxy)ethylphosphorodi- thioate (malathion) is a widely used organophosphorus pesticide. Its increased application is evidenced by a steady rise in production, approaching 35 million lb in 1971 ( 1 ) . This nonsystemic insecticide and acaricide has received wide usage primarily because of its low mamma- lian toxicity and its biological selectivity. I t is used in ag- riculture for insect control and in mosquito control by di- rect application to water areas. Malathion can therefore enter the aquatic environment either directly or through agricultural runoff.

Because of its wide usage, extensive research has been stimulated concerning the biological degradation of mala- thion. Most studies to date have revolved around its deg- radation in soils. Matsumura and Boush ( 2 ) reported rapid degradation of malathion in cultures of the soil fun-

gus, Trichoderma viride, and a bacterium, Pseudomonas sp., isolated from soil, The products of metabolic degrada- tion were mainly carboxylic acid derivatives of malathion, indicating carboxylesterases are probably involved in mi- crobial metabolism. High demethylation activity was also evident in some Trichoderma uiride varieties indicating another degradation pathway. Walker and Stojanovic ( 3 ) found that malathion is readily degraded by an Arthro- bacter sp. The four metabolites produced were identified as malathion half-ester, malathion dicarboxylic acid, po- tassium dimethyl phosphorothioate, and potassium di- methyl phosphorodithioate. The studies of Mostafa et al. ( 4 ) also indicate that malathion is readily degraded. These researchers report that the fungi, Penici l l ium rot- a t u m and Aspergillus niger, metabolized 76 and 59% of the malathion in the medium within 10 days. Both fungi degraded the insecticide through carboxylesteratic hydrol- ysis as well as by a demethylation process.

Data concerning the fate of malathion and its degrada- tion products in natural waters are not available. Most in- formation concerning its breakdown by aquatic microor- ganisms pertains to its toxicity to such organisms. Algal growth was reported to be inhibited by malathion ( 5 ) ; Sanders and Cope (6) found that malathion was toxic to two species of daphnids; and Macek and McAllister (7), in their insecticide susceptibility studies of fish (catfish, bullhead, goldfish, minnow, carp, sunfish, bluegill, bass, rainbow salmon, brown salmon, coho salmon, and perch), reported considerable species differences, the lowest toler- ance being coho salmon (96-hrTL50 = 0.101 ppm).

An evaluation of the environmental impact of mala- thion on the aquatic environment requires an under- standing of the breakdown processes, biological and other- wise, of the insecticide. An integral part of this under-

Volume 9, Number 2, February 1975 135