J. of university of anbar for pure science : Vol.4:NO.3 : 2010

ISSN: 1991-8941

Environmental Risk Assessment in Baghdad City byDetermination of Lead Level in Soil Samples

Hussian Hassan KharnoobUniversity of Tikrit - College of Pharmacy.

Accepted:30/12/2010Received: 26/5/2010

Abstract :The concentration of lead has been determined in different sites of Baghdad duringsummer season 2008.Analysis was carried out using flame atomic absorption spectrophotometertechnique (FAAST) at wavelength 217 nm and air-acetylene flame. The lead level was found in aparticulate fraction in some soils of AL-Karkh is more than in AL-Rusafsa sites of Baghdad. The levelsapproach the hazardous limits in most sites as a result of industrial activities and exhaust cars which arevery crowded in Baghdad streets.

Key words : Environmental , Risk Assessment ,Baghdad ,Lead , Soil Samples

IntroductionBaghdad, with its about six million inhabitants,the biggest and the most industrialized city inIraq. Due to its development and increasingtraffic volume eseptically about two millionsused cars that enter Iraq from EU countriessince March 2003. it is expected to suffer morefrom lead contamination; on other hand Iraqigasoline still has tetraethyl lead as antiknocking agent, as well as the presence of abig car batteries factory (north east Baghdad)which uses old technique and it has noemission control devices at all. There is hardlyany information regarding the dispersal anddistribution of lead in different parts of thecity. Lead is one of the non essential traceelements. It is useful but toxic lead is one ofthe commonest and most widely distributed ofenvironmental metal poisons [1,2]. The naturaland anthropogenic sources such as mining,

Major Componentssmelting and leaded gasoline generatelead in soil [3]. Pb is more dangerousto children than adults because ofbabies and children's growing bodiesabsorb more lead, children's brain and nervoussystem are more sensitive to damaging effectsof lead[4]. There is a relation betweenincreasing exposure to lead and elevation in

lead blood levels [5]. In china as an example ofrapid developing country, children living inindustrial area and in area with heavy traffichad high lead levels in their blood [6].Sediments play major role in leadtransformation within food web ; ingestedsediment may be a major vector in the uptakeand concentration of hazardous amount of leadin organisms use sediments as source of theirfood[7]. The toxicity of lead is very complex.Inorganic lead, Pb+2 is a general metabolicpoison and cumulative in human.The inorganiclead compounds exist in environment [8] arelisted in Table (1).

PbBrClα-2 PbBrCl.NH4Cl

Minor Componentsβ-2 PbBrCl.NH4ClPbBrCl.2NH4Cl3Pb(PO4)2. PbBrClPbSO4

PbO.PbBrCl.H2OTable(1) Inorganic lead in Environment

Lead bromochloride (PbBrCl) arises fromreaction of lead oxide, formed by combustionof the tetraalkyllead additives, withhalogenated scavengers that are added to thefuel, represent the major compound in vehicleexhausts [9].

Pb(C2H2)4+O2+halogenated scavengers CO2+H2O+PbCl2+PbClBr

J. of university of anbar for pure science : Vol.4:NO.3 : 2010

Lead inhibits enzyme system necessary for theformation of hemoglobin through stronginteraction with –SH group[10].Lead (II) canreplace Ca+2 in bones so tending to accumulateover long periods (lead alkyls such astetraethyl lead are even more poisonous thanPb+2 species which is readily adsorbed fromrespiratory tract , gastrointesinal tract and skin

where as the insoluble stable lead sulphate ,sulphide and chromate are poorly adsorbedfrom gastrointestinal tract[11]. The absorbedlead is carried by red blood cells through body.It binds to bone, lungs , kidneys , brain andspleen [12].Tablel(2) represents therelationship between dose effect for adversehealth effect of lead exposure [13].

Table(2) Dose-Effect Relationship for Adverse Health Effects of Lead Exposure.Pb in blood(µg/L) Health Effects

120 Rising severity death100 Rising severity death80 Severe CNS effect60 Overt anemia40 Nerve Conduction velocity20 Hemoglobin Deficiency10 Vitamin D Deficiency

Experimental and Results

The experimental design in this research was proceed as in the following scheme:

The locations for this research lie in Baghdadcity (Figure -1). Baghdad is the capital ofIraq with

Population density about 1160 person per Km2

situated on the Tigris River at 33.23 N latitudeand 44.23 E longitudes.

Soil sampling and aaش

Sampling sieving

Drying the Samples

Extraction of Pb by MagnesiumChloride

Determination of ionic lead byFAAS

Extraction of Pb by Conc. NitricAcid

Determination of total lead by FAAS

J. of university of anbar for pure science : Vol.4:NO.3 : 2010

Figure (1) Location of SamplesSamplingFifty surface soil samples from Baghdad soilwere collected during summer season 2008.More attention was paid to the Pb distributionaround car batteries factory surface soil (0-5)cm were collected and drying was done atroom temperature over night. Twenty fivesamples were collected from each site ofBaghdad at 12/4/2008, five samples from eachlocationSieving and ExtractionThe samples were brought to completedisaggregating by passing through a 2 mmsieve, using a stainless steel tool to separate thelarge soil particles. The duplicated sample (1gm) was digested with 10 ml concentratednitric acid and heated to reduce the volume to2 ml then filtered through 541 filter paper. The

volume was diluted to 25 ml with distilledwater and the analysis was done by Varianflame atomic absorption spectrophotometer atthecentral laboratory in the ministry ofenvironment in Baghdad . The wave lengthwas 217 nm and flame of air – acetylenemixture for the total lead was used. The resultsobtained are listed in Table (3). Ionexchangeable lead was extracted from thesample by shaking (1g) of the sample with 10ml of (1M) magnesium chloride for 1 hour,filter and complete the filtrate to 25 ml withdistilled water. The analysis was done as fortotal lead using calibration standard curvemethod. The results obtained are shown inTable (4)

Table (3) Concentration of lead in Al-karkh sites (µg/g)Site Total lead Ionic LeadAl-jihad 90500 10150Al-lliwia 41000 2025Al-Biaia 29200 620Al-Yarmook 7300 50Al-Dora 116 9

Table (4) Concentration of Lead in Al-Rasafa Sites (µg/g)Site Total lead Ionic LeadAl-Waziria 42000 1750Bab-Almoathim 4000 30Bab-Alsharji 1115 25Al-Nahtha 320 20Al-Shaikh Omer 65 10

J. of university of anbar for pure science : Vol.4:NO.3 : 2010

DiscussionThe results in Table (3) which is described inFigure-2- indicate that the soils are highlycontaminated with lead, but total concentrationof lead is not good indication forenvironmental pollution [14], therefore the

pollution is depending upon the concentrationof ionic formula of lead than on its totalconcentration in soil samples.

0

15000

30000

45000

60000

75000

90000

1 2 3 4 5

Locations

Co

ncen

trati

on

of

Lead

Total Lead

Ionic Lead

Figure (3) Total Concentration and ionic formula of lead in Al-Karkh Site

The pollution in the different soil sites of Al-Karkh is in order of Al-Jihad > Al-Biaia > Al-Alliwia > Al-Yarmook > Al-Dora .The resultsin Table (4) show that the soils in Al-Rasafasites are less contaminated with lead than inAl-Karkh sites in the following order :-

Al-Waziria > Bab-Almoathim > Bab-Alsharji > Al-Nahtha > Al-Shaikh Omer.Figure (4) describes the total concentration oflead in Rasafa soil sites.

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

1 2 3 4 5

Location

Co

ncen

trati

on

of

Lead

Total Lead

Ionic Lead

Figure(4) Total Concentration and Ionic Formula of lead in Al-Rasafa Site

The ionic exchangeable of lead is available tobiota to be absorbed [15] ,adsorbed[16],ingested[1] and inhaled[18] by human ,therefore ionic lead is more health effectsthan total lead[19] . The accuracy and

precision of analytical method used in thiswork are shown in Table (5). They indicatethat the method is reliable, sensitive and highlyrecovered.

Table( 5) Accuracy and Precision of the Analytical MethodConcentration added

(µg/ml)Concentration found

(µg/ml)Recovery (%) R.S.D. (%)

50 48.7 97.4 0.661850 48.5 97.0 0.588350 49.5 99.0 0.687

R.S.D = Relative Standard Deviation

J. of university of anbar for pure science : Vol.4:NO.3 : 2010

ConclusionOverall the sites used in this research areconsidered to represent moderate risk to thehealth of population according to the resultsobtained by many workers[20]. Theconcentration of ionic lead in soil which ishazard to children(20-25)µg/g, while theconcentration of total lead (320-3925) µg/g ,the previous numbers indicate that lead is moreeffective on children than on adults . Thehemoglobin (Hb) expected for children livingin contaminated soil should be low due tointerfering of lead with an essential enzymeaminoevulinic acid dehydrates which isimportant in the biosynthesis of heme [21]

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