A Survey Of Lead Pollution In Chhattisgarh State, Central India

Springer 2006

Environmental Geochemistry and Health (2006) 28:11–17 DOI: 10.1007/s10653-005-9006-0

A survey of lead pollution in Chhattisgarh State, central India K.S. Patel1,4, K. Shrivas1, P. Hoffmann2 & N. Jakubowski3 1 School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur, CG, India 2 Chemical Analytics, Department of Materials and Earth Sciences, Darmstadt Technical University, Petersenstrasse 23, D-64287 Darmstadt, Germany 3 Institute for Analytical Science (IAS), Bunsen-Kirchhoff-Strasse 11, D-44139 Dortmund, Germany 4 Author for correspondence (e-mail: [email protected])

Key words: Central India, lead pollution, soil, sediment, water Abstract Lead (Pb) is of major environmental concern due to its toxicological importance. The anthropogenic emission of Pb is at least 100 times higher than natural emissions. Soil and dust are significant sources of Pb exposure. Lead is generally immobile in soil and accumulates in the upper layers. Lead particles may enter homes via shoes, clothes, pets, and windows. Central India is rich in deposits of natural resource materials such as coal, pyrite, dolomite, and alumina that contain Pb and other heavy metals at the trace levels, and the substantial exploitation of these materials has tended to increased contamination of water and geological formations. Here we present data on Pb concentrations in the water, soil and sediment samples (n=158) collected from 70 locations in Chhattisgarh state, Raipur region. Lead concentrations in the surface water (n=44), groundwater (n=44), soils (n=60) and sediments (n=10) ranged from 6 to 1410, 3 to 52, 12.8 to 545, and 31 to 423 lg g)1, with mean values of 305, 16, 102 and 190 lg g)1, respectively. Most of the Pb fractions of >80% can be leached out with the chemical extractants EDTA, acetic acid, and hydroxylamine hydrochloride. Lead has accumulated in the soil clay fraction due to its relatively large surface area and decreases with increasing depth in the soil profile.

Introduction Lead (Pb), an extremely stable element, is very toxic to humans and animals. It is a neurotoxin and lead poisoning is one of the most common pediatric health problems in India. The average concentration of Pb in the Earth’s crust is around 13 lg g)1 but there is considerable variability in natural concentrations because of inputs from mineralized deposits of Pb. However, a major feature of the environmental chemistry of Pb is the general diffuse pollution in topsoils from a range of sources, including mining and smelting, recycling of sewage sludge and from motor vehicle exhausts. Consequently, Pb is known to show significantly enhanced levels in surface soils of

some regions of the world (Reeder & Shapiro 2003). Because Pb is not biodegradable, once soil has become contaminated it remains a long-term source of Pb exposure. There are heavy deposits of fossil fuels such as coal and of minerals such as pyrite, alumina, and dolomite in central parts of India, including Chhattisgarh state. There are several thermal power plants for energy production, heavy industries such as steel, aluminum and cement plants. These heavy industries tend to increase the deposition of Pb and other metals in the environment. Here, we present the results of a preliminary survey on the distribution, speciation, mobility and sources of Pb in Chhattisgarh state, Central India.

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Materials and methods Study area Chhattisgarh is 146,361 km2 in area and is one of the mineral-rich states of India. It is situated in a peninsular plateau at 17–22N, 80–82E at altitudes of ‡300 meters above sea level (Figure 1) and has a population of 20 millions. It is richly endowed with natural resources including a 43% forest cover and has rich deposits of limestone, iron ore, copper ore, rock phosphate, manganese ore, bauxite, coal, and asbestos. The State produces substantial amounts of rice grain and supplies food grain to 600 rice mills. Some details of major industries, thermal power plants, mines and rice mills in operation are summarized in Table 1.

the sample was then acidified with 1% (v/v) ultra pure nitric acid. All the samples were filtered through Whatman no. 42 filter paper. Soil and sediment samples were collected from 70 sites and placed in polyethylene bags. The samples were air dried and passed through a 0.2mm sieve prior to analysis for total Pb, Ni, and Cu. Reagents Analytical grade acetic acid, hydroxylamine hydrochloride in ethylenediaminetetra-acetic acid, hydrochloric acid, and nitric acid were used for leaching of the metals. Standard Pb, Cu and Ni solutions (1000 mg l)1) supplied by E. Merck were used for calibration. Soil properties

Sampling Water, soil and sediment samples were collected from different locations in urban and industrial sites of Chhattisgarh state between January and February 2003 using procedures described by Keith (1991). Surface water and groundwater samples were collected from 100 points and stored in pre-cleaned 500-ml polyethylene bottles. The pH of the sample was immediately measured and

The soils of this region have pH values of around neutral to slightly acidic in the range 4.6–7.8 and most have low P status, usually <10 mg kg)1. Extraction Four extractants, 0.11 M acetic acid (AA), 0.1 M hydroxylamine hydrochloride (HAHC) in HCl (pH=2), 0.1 M ethylenediaminetetracetic acid

Fig. 1. Map of Chhattisgarh state showing location of Raipur and Korba regions.

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Table 1. List of emission sources in Chhattisgarh state. Industry

Consumption year)1

Production

Thermal power plants (National Thermal Power Corporation), Korba Cement plants (6) Bhilai Steel Plant, Near Raipur Rice mills (>600)

15 MT coal

5000 MW electricity

15 MT dolomitic limestone 5 MT iron ore 4 MT

Aluminum plant (BALCO), Korba Ferro alloys Sponge iron South-Eastern Coal Fields Korba

4 MT bauxite

11 MT 3.153 MT 1 MT of raw rice and 1.8 MT of parboiled rice in this area 1 MT aluminum 0.8 MT 1.3 MT 38 MT coal

9 underground and open-cast mines extending over 21627 ha

(EDTA) and aqua regia, were used for leaching of acid-soluble, reducible, complexed and total fractions of the metal in soil and sediment samples (Chen et al. 2001). A 0.50-g soil or sediment sample was transferred to a 25-ml centrifuge tube and a 10-ml aliquot of extractant was added. The mixture was shaken for 16 h at room temperature by shaker and all the extractants were decanted off and retained for analysis of metals: Pb, Ni and Cu. For the determination of total metals, the sample was placed in a 100-ml round bottom flask equipped with a water condenser fitted with a U-tube (filled with dilute nitric acid). A 10-ml aliquot of aqua regia was added and the sample was digested over a sand bath for 4 h. After digestion, the extract was transferred into a 25-ml volumetric flask and made up to volume with Milli-Q water. Analysis A flame atomic absorption spectrophotometer (GBC, AAS-932) was employed for analysis of Pb, Ni, and Cu using an air–acetylene flame. The wavelength, slit and lamp current used are summarized in Table 2. A graphite furnace atomic absorption spectrophotometer (GBC, AAS-932 equipped with GF-3000) was used to determine Pb in water samples. A 20-ll aliquot of the sample solution was used. The ashing and atomization temperatures were 400 and 2000C. A blank was used to avoid contamination from the sample preparation and chemical reagents. An inductively coupled plasma-mass spectrometer (ICP-MS) PQ II Turbo Plus (VG Elemental, Winsford, UK) was used at the Institute for Analytical Science (IAS), Dortmund, Germany to compare some of the data

Table 2. Operating parameters for the acetylene – air flame AAS determination of Pb and other heavy metals. Element

Wavelength (nm)

Slit (nm)

Lamp current (mA)

Pb Ni Cu

217 324.7 244.8

1 0.5 0.2

5 4 5

with the results of AAS. A Meinhard nebulizer and a Scott type spray chamber made of quartz were used. The peristaltic pump (Gilson Minipulse 3) had a sample delivery rate of 0.7 ml min)1, tuning was performed on 140Ce, and the forward power was 1400 W. The flow rates of argon gas used were 16, 0.9 and 1.0 l min)1 for cooling, auxiliary and nebulizer gas, respectively. Conventional Ni cones were used. An external calibration with six standard samples was carried out using a multi-element standard solution (E. Merck) with subtraction of a blank value. The work: leaching of the heavy metals with extractants (i.e. AA, HAHC and EDTA), and analysis of the metal contents in the extract was carried out in the TU Darmstadt, Germany using technique: Perkin Elemer 4100-ZL graphite furnace atomic absorption spectrophotometer.

Results Lead has unique chemical properties and is found in many common consumer products and many sites in the environment. Lead from these many different sources can enter and contaminate the surroundings. Large amounts of effluents are

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Table 3. Distribution of lead in water, soil and sediment samples. Site

Soil (lg g)1)

Steel plant Power House Bhilai-3 Bhilai, Sector-I Bhilai, Sector-II Bhilai, Sector-III Bhilai, Sector-IV Hudco Supela Civic Centre Durg-I Durg-II Durg-III Durg-IV Durg-V NTPC-1 (Korba) NTPC-II (Korba) BALCO (Korba) CSEB-East (Korba) CSEB-West (Korba) Korba city Kusmunda (Korba) Gevra (Korba) Manikpur (Korba) Dipka(Korba) Tatibandh (Raipur) Ashram (Raipur) Tatyapara (Raipur) Jaistambh (Raipur) Main Hospital (Raipur) Shankar Nagar (Raipur) Telibandha (Raipur) Railway station (Raipur) Bus stand (Raipur) Industrial area (Raipur) Dabhara Sakti Nandghat Bilaspur-I Bilaspur-II Dalli-rajhara Rajnandgaon-I Rajnandgaon-II Dongargarh Chikola Kurud Bankundpur Ambikapur Baladela-I Baladela-II Pithora Basana Saraipali Mulethitola Bhadsena Meregaon Kaudikasa

320 545 271 295 246 230 234 265 178 271 86 72 101 61 51 198 212 125 120 161 176 92

Sediment (lg g)1)

315 423

Groundwater (lg l)1)

121 146 115 105 84 87 79 111 105 98

13 28 18 21 13 11 14 17 19 16

1200 1050 1205 990 1110 1345 1260 885 1410 776 61 50 39 70 62 40 65 89 65 99

41 30 36 17 15 51 33 19 52 16 12 13 8 14 11 7 8 13 9 15

29 25 12 10

17 13 3 5

8

4

13 6

7 3

18 15 13 8

9 8 5 4

7

3

11

4

66 88

267

208 298 87

67 102 99 64 76 134 88 79 112 121 98 129 13 14 21 31 27 25 28 24 20 19 18 23 15 45 40 25 23 20 17 20 15 19

Surface water (lg l)1)

150

50

31

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Table 3. Continued. Site

Soil (lg g)1)

Sonsaytola Joratari Thailitola

Sediment (lg g)1)

Surface water (lg l)1)

Groundwater (lg l)1)

13 20 21

emitted by stagnant point sources such as steel plants, cement plants, and thermal power plants to the environment of Central India and subsequently deposited in the geosphere and the hydrosphere. Lead in surface soils Lead is immobilized by the organic soil components and Pb deposited from the air is generally retained in the upper 2–5 cm of undisturbed soil (USEPA 1986). Urban soils and other soils that are disturbed or turned under may be contaminated down to far greater depths. We collected 60 soil samples for the analysis of Pb from various locations. The total Pb concentration ranged from 12.8 to 545 lg g)1 with mean and median values of 102 and 73.9 lg g)1, respectively and a very high value of standard deviation (SD±103 lg g)1), possibly due to large heterogeneity in the distribution and content of mobile and static sources (Table 3). The spatial variation of Pb in the soil was studied. The highest Pb concentrations were observed in the soils of the iron smelting (Bhilai) and coal burning (Korba) sites, perhaps due to emission of effluents from, inter alia, pyrite smelting (capacity 5 MT year)1) and coal burning (capacity 15 MT year)1). The mean soil Pb concentration (n=15) in the iron smelting sites ranged from 51.0 to 545 lg g)1 with mean, median and SD values of 215, 234 and ±132, respectively. The soil Pb concentration of the coal burning sites (n=10) ranged from 67.4 to 212 lg g)1 with mean, median and SD of 134, 122.5 and ±50, respectively. The SD value was at least 2-fold less than for the coal burning sites, possibly due to the distribution of high frequency emission sources (thermal power plants, aluminum plants, and coal mines) over a large area. The soil Pb concentrations in urban and rural sites ranged from 64.5 to 129 and from 12.8 to 31.3 lg g)1 with mean and SD values of 100±22.2 and 23.6±7.7 lg g)1, respectively. Seasonal variation in soil Pb contamination was examined at one site, Bhilai-3. The highest con-

centration of Pb (271 lg g)1) was observed in the winter (December–February) due to higher deposition and lower volatilization of Pb. The lowest concentration (231 lg g)1) was observed in the rainy season (July–September), possibly due to dilution by rainfall. The lower concentration of (250 lg g)1) observed was in the summer season (April–June) may be due in part to higher volatilization of the organic Pb. Lead in sediments The total Pb concentration in sediment samples derived from 10 different ponds ranged from 31 to 423 lg g)1 with mean, median and SD of 190, 179 and 133, respectively (Table 3). The total Pb concentrations in sediments are generally higher than in the soils, perhaps due to leaching. The sediments of Central India are much more contaminated than other sites worldwide (Donazzolo et al. 1981; Neto et al. 2000; Tam & Wong 2000), and this may be due to intensive exploitation of natural resources such as coal, pyrite, alumina, and dolomitic limestone. Lead in surface waters Lead has a tendency to form compounds of low solubility with the major anions found in natural waters. In the natural environment, the divalent form (Pb2+) is the stable ionic species. Hydroxide, carbonate, sulfide, and, more rarely, sulfate groups may act as solubility controls in precipitating Pb from water (USEPA 1986). The total Pb concentration in stagnant surface water ranged from 6 to 1410 lg l)1 with mean, median and SD of 305, 74 and ±463 (Table 3). Very high concentrations of Pb were observed in water samples from steel and thermal power plant sites, probably due to atmospheric deposition and leaching from contaminated sediments. Lead in groundwater Percolation of Pb species in the groundwater of contaminated sites such as Korba may be due to

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Table 4. Examples of lead contamination in soils and sediments worldwide. Location

Sample material

Pb (lg g)1)

References

Belize Murcia, Spain Naples city, Italy Brazil Elbe river, Germany Ganges Estuary, India Gulf of Venice, Italy Hawaii, USA Marmorilik, W. Greenland North sea, UK Sai Kung, Hong Kong Central India

Soil Soil Urban soil River sediment Estuary sediment Estuary sediment Gulf sediment Road sediment Sediment Estuary sediment Estuary sediment Soil Pond Sediment

<5450 1572 100 64–174 25–142 12–115 5–84 4–1750 8922±622 52–207 85.5 12.8–545 31–423

Reeder and Shapiro (2003) Walker et al. (2003) Imperato et al. (2003) Neto et al. (2000) Shoer et al. (1982) Subramanian et al., (1988) Donazzolo et al. (1981) Sutherland (2003) Larsen et al. (2001) Smith and Orford (1989) Tam and Wong (2000) This study

the extensive exploitation of coal deposits. Lead also diffused into groundwater of urban sites with aquifers with a low water table. The Pb concentration ranged from 3 to 52 lg l)1 with mean and SD values of 16, 13, and ±12, respectively (Table 3).

Discussion Size distribution and mobility of Pb The Pb content of soil and dust varies dramatically as a function of particle size (Duggan & Inskip 1985). Several studies have reported that the Pb content of soil, street dust, city dust, and house dust increases as the particle size decreases. Accumulation of Pb and other metals (Ni and Cu) in different size range categories of soil particles (2–0.05 mm) was examined. Lead accumulation in clay particles increases as the mesh size decreases (r=)0.81) with slope and intercept of )150.5 and 327. Similarly, Ni (r=)0.99) and Cu (r=)0.73) concentrations increase as the particle size decreases, with slope and intercept of )82.7, )435.5 and 158.4, 780.5, respectively. Slope and intercept increase in order: Ni Pb Cu, perhaps due the high adsorption efficiency of the mud. Lead accumulation in soil particles decreases as the depth profile increases, perhaps due to atmospheric deposition and lower solubility of the Pb compounds in water. In the soils of Central India, Pb accumulation shows a strong negative correlation with depth of profile (r=)0.98) with slope and intercept values of )2.89 and 233.7, respectively.

Leaching of Pb, Cu and Ni Metallic Pb is not itself toxic to humans (Wallace and Wallace, 1994). Bioavailable forms of Pb are toxic because they are easily taken into the body and cause plumbism (acute lead poisoning). Four fractions of Pb from weakly held to strongly held in the soil were extracted with four chemical extractants, AA, HAHC, EDTA and AR, respectively. The largest fraction of Pb (>80%) was extractable with EDTA (50.0–72.7%) and HAHC (7.5–32.0%) whereas a small fraction was extracted with AA (4.0–7.0%) compared with AR (‘total’ Pb). Similarly, >80% Cu was leachable with the extractants EDTA, HAHC and AA, unlike Ni (data not shown). Correlation of Pb with other heavy metals Lead showed good correlation with Ni and Cu both in soils and sediments. The mean (n=5) concentrations of Pb, Ni and Cu in surface soils observed were 122, 60 and 236 lg g)1, respectively. The mean (n=5) concentrations of Pb, Ni and Cu in the pond sediments were 119, 141 and 279 lg g)1, respectively. The Pb concentrations in sediments and surface soils are very similar but Ni and Cu were at least two fold higher in the sediments. Sources of Pb Several major sources of lead exposure have been identified. The important sources of lead exposure in this region of the country would be expected to

pb pollution in central india be mineral smelting and coal burning. The concentration of Pb in the surface soil of Central India was found to range from 13 to 545 lg g)1 with a mean value of 115 lg g)1, and is probably elevated by addition from anthropogenic sources. The Pb concentration in soils and sediments shows good positive correlations with the ferro-alloying metals Ni, and Cu. The static point sources such as iron ore smelting are much more prominent than other sources with coal burning observed to be the second most prominent static anthropogenic source. Lead contamination in soils and sediments Lead is a stable and immobile metal. Soils and sediments of various sites worldwide contaminated with high levels of Pb are summarized in Table 4. Very high Pb concentrations (>100 lg g)1) have been reported in soils in, for example, Belize, Italy, and Spain. Estuaries, gulfs, roads and river sediments at sites in Brazil, Hawaii, Greenland, North India, and UK are contaminated with elevated levels of Pb. In Central India, a large area (4.0104 km2) is thought to be contaminated with Pb due to human activities such as metal smelting, energy production, and coal and iron mining. Conclusions High and variable Pb concentrations (13–545 lg g)1) have been found in the environment of Central India. The major fraction (>80%) of Pb is in leachable forms. In contaminated sites, the stagnant surface water is also contaminated with Pb above the tolerance limit (15 lg l)1) and Pb has percolated into the groundwater aquifers. Iron ore smelting and coal burning processes are considered to be prominent emission sources of Pb and other heavy metals (Sahu 1987). Young children are more likely to play in dirt and to place their hands and other objects in their mouths, thereby increasing the opportunity for soil ingestion. The Pb incorporated into dust and soil may become a long-term source of Pb exposure for children in this region. Acknowledgements We thank the Alexander von Humboldt Foundation, Bonn, for providing a Fellowship to K.S.P.

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