HEAVY METALS CONTAMINATION OF TEA ESTATES … · heavy metals contamination of tea estates soil in...

International Journal of Advancements in Research & Technology, Volume 2, Issue4, April-2013 215 ISSN 2278-7763

Copyright © 2013 SciResPub.

HEAVY METALS CONTAMINATION OF TEA ESTATES SOIL IN SIVASAGAR AND DIBRUGARH DISTRICTS OF ASSAM, INDIA

T.N. Nath

Associate Professor , Department of Chemistry, Moran College, Sivasagar, Assam, India. [email protected] K.G.Bhattachayya Professor, Department in Chemistry, Gauhati University, Guwahati, Assam, India.

Abstract: The aim was to determine the concentration of heavy metals in tea estates

soil in the Dibrugarh and Sivasagar districts of Assam, India. Soil samples from twenty

tea estates and a control site were analysed for selected heavy metals namely: Cd, Cr,

Cu, Fe, Pb, Mn, Ni and Zn. Soil samples were obtained triplicates and at depths of 0 to

15(surface), 15 to 30(subsurface I) and 30 to 60(subsurface II) cm respectively in the

month of December every year from 2007 to 2009. According to the results, Cd, Cr, Cu,

Fe, Pb, Mn, Ni and Zn contents of soils ranged from 1.52 to 2.83, 1.28 to 2.80 and 1.19

to 2.69 mg/kg; 68.73 to 102.02, 56.0 to 94.07 and 46.58 to 88.93 mg/kg; 16.73 to 36.33,

15.35 to 31.73 and 13.17 to 29.13 mg/kg; 4.933 to 10.766, 4.405 to 9.962 and 3.206 to

8.531 mg/g; 25.17 to 52.88, 20.17 to 41.67 and 16.97 to 33.70 mg/kg; 118.53 to 420.53,

103.73 to 390.33 and 92.07 to 377.50 mg/kg; 34.40 to 65.37, 30.67 to 60.00 and 19.13

to 46.27 mg/kg and 21.43 to 65.20, 21.07 to 56.47 and 17.70 to 48.87 mg/kg for the

surface, subsurface (I) and subsurface (II) soil respectively. Evidence of contamination

of these soils was obvious when these values were compared to the control soil. The

results revealed that the concentration of the heavy metals were below the typical

agricultural soil critical level but higher the soil control. Among these Cu, Fe, Mn and

Zn are micronutrients and Cd, Cr, Ni and Pb are soil pollutants. Heavy metals can create

some harmful effects on the ecosystem and cause the environmental pollution due to

their toxic impacts on plants, animals and human beings.

Keywords: Heavy metal, micronutrients, soil pollutants, eco-system, environmental

pollution and toxic impacts.



Introduction: Soil testing is a key weapon in assessing the fertility of soil [40]. Soil

testing results can be effectively used for assessing plant nutrient requirement [53]. To

increase the tea production, a huge amount of fertilizers are applied in the tea estates

soil. Fertilizers can enhance the soil fertility and also yield the productivity of tea. But

fertiligers itself contain sufficient amount of heavy metals. Therefore, the heavy metal

concentrations in soils gradually increased.

Soil is a medium of acting as a sink for natural and anthropogenic pollutants [18].

Humans are introducing heavy metals into the environment. Heavy metals were no

longer restricted to local area but were distributed over a wide area by means of air,

water and soil. When the heavy metals are carried into the soil, they will accumulate

there with time and enter into the ecosystem or the food chain causing harm to human

health [27], [82]. Soil heavy metal contamination has occurred since prehistoric times,

but the extent of contamination has increased by the geogenic, rate of urbanization and

several anthropogenic activities. The anthropogenic activities such as

mining and smelting operation, application of sewage sludge, inorganic fertilizers

animal wastes and pesticides [4], [55] ,[38], [54]. Anthropogenic contamination with

heavy metals is a worldwide problem that causes massive water and soil pollution [16],

[66]. Heavy metals that have contaminated industrialized areas, roadside soils,

riverbanks, and urban areas are among the most serious environmental hazards [45].

The management of metal-polluted soils is now of major concern for most industrialized

countries because of the ubiquity of the metals, their environmental persistence and

their hazardous effects for the environment and human health [28], [20], [64], [23].

Various remediation methods, such as soil excavation and land filling, may be very

helpful to contribute to restore metal-polluted soils [52]. These methods are usually

expensive and some of them have unfortunately induced adverse effects on the

biological activity, the structure and the fertility of soils. An alternative stagedy is the

use of plant species to stabilize or remove pollutants from soils, defined as

phytoremediation [69]. Phytoextraction technology is defined as the use of plants to

remove metals from soils into the harvestable part of their biomass [21]. Heavy metal

uptake and accumulation by plants depends on metal speciation, mixed contamination,

soil factors (pH and CEC) and plant characteristics (root depth, species, age etc.) [9],

[15]. One of the key steps in phytoextraction remains the selection of plant species [52]



Unlike other heavy metals such as Cu, Zn, Mn and Fe that are essential to living cells at

low concentrations, Pb does not have any known biological role [67]. While the

introduction of unleaded gasoline has contributed to the decrease of lead emissions into

the environment, lead pollution is still significant due to historical loads as well as to the

continuing deposition from other sources including, mining, smelters, and batteries

disposal [1]. A debate exists among researchers whether absorbed metals are

bioavailability, while some claim that only soluble metals are available [1], [33], [65].

Others demonstrated that some metals e.g. Cd and Pb are bioavailable even when

absorbed to particulate matter [34], [13]. Such discrepancies on the need, scale, costs,

and clean up goals of contaminated soils [12]. Numerous studies on contaminated soil

suggest that physiochemical soil properties such as pH and clay and organic matter

content are the major factors controlling heavy metal toxicity and bioavailability [36],

[61], [60]. It was demonstrated that only desorbed Pb is bioavailable, while bound Pb is

not [45]. Because of their enormous adsorption capacity, organic matter and Fe-oxide

are capable of taking up very large amounts of Pb and do not release any detectable Pb

to solution, diminishing the bioavailability of Pb [25], [71], [31]. The bioavailability of

Pb depends on the type of the soil and the components it contain. Arid and semiarid

soils which contain large amount of carbonates and have little organic matter will effect

differently the solubility of Pb and hence its bioavailability compared with temperate

soils which usually lack pedogenic carbonate but have large amount of organic matter

[45].

Sewage sludge, an envitable by product of waste-water treatment, contains high

proportions of organic matter and plant nutrients [79] [49], [70]. The use of it improve

the physical and chemical properties of soil is recommended [46], [74]. It contains

contaminants, and excessive salts, which much also be considered in its agricultural use

[58]. Heavy metals in sewage sludge may enter the food chain through crops and affect

human health [75]. The physicochemical effects of the long-term use of sewage sludge

in the amendment of topical soils are still uncertain [48], [56],[77].

The accumulation of heavy metals in plants has been a serious environmental

concern because their uptake by plants from contaminated soils is the principal

processes by which heavy metals enter the food chain and then to men and animals and

are relatively toxic at levels slightly above than those required for maintaining normal



metabolic activities of body [32], [62], [24], [18], [36]. The uptake of heavy metals by

plants from soil depends on their concentration in soil, organic matter, soil, clay content

and on their specific geochemical properties [8]. Plants species differ not only in heavy

metals’ uptake but also with respect to the translocation of metals to various plant

organs [42] which influence heavy metal concentration in food chain and food stuffs

[43]. The degree of toxicity depends upon the form in which they are present. Thus,

organo-lead is much more poisonous than the inorganic form. The oxidation state of

metals also plays an important role in this regard. So, the hexavalent chromium is more

toxic than its trivalent forms [6]. The present work is an attempt to study the census of

heavy metal concentration of tea estates soils in Dibrugarh and Sivasagar district.

Materials and Methods:

The studies were conducted in twenty tea estates soil which covers approx 7000

hectares of land in Dibrugarh and Sivasagar districts. Sivasagar district is one of the

most important historic and industrial City of Assam. The Sivasagar district is located

from 25045/ to 27015/ N latitude and 94025/ to 95025/ E longitude. It has elevation of

86.6 Mts. above the sea level. It is surrounded by Lakhimpur district and Dibrugarh

district in the north, Arunachal Pradesh and Dibrugerh district in the east, Arunachal

Pradesh and Nagaland in the south and Jorhat in the west. The geographical area

covered by sivasagar district is 2668 sq km.

The physiography of Sivasagar district is mainly valley. The tributaries of

Brahmaputra River like dimow, Darika, Disang, Dikhow etc. flows through this district.

Sivasagar district carries a pleasant weather throughout the year. The temperature

ranges from 80C to 180C in winter and 150C to 350C during summer. The district is

characterized by highly humid atmosphere and abounded rains. The average rainfall is

about 230 cm. The regular rains of the summer generally prevent the prevalence of the

hot weather.

There are 119 tea estates in Sivasagar district which covered the area of 88008

Hectares land. Besides these tea estates, 80 registered small tea growers and 4004 small

tea growers, this covers the 5356 Hectares of land in this district.



Fig.1 Location of study area and soil sampling stations.



Dibrugarh, the head quarter of Dibrugarh district is famous as the “Tea City of

India”. Dibrugarh district is situated in the eastern part of Assam. The Dibrugarh district

extends from 27005.38/ N to 27042.30/ N Latitude and 94033.46/ E to 95029.80/ E

Longitude. It is surrounded by Dhemaji district and a part of Lakhimpur district in the

North, Tirap district of Arunachal Pradesh and a part of Sivasagar district in the South,

Tinsukia district in the East, and Sivasagar district in the West. The geographical area

covered by Dibrugarh district is 3381 sq km.

The physiography of Dibrugarh district is mainly valley. The Dibrugarh district is

located in the north eastern corner of the Upper Brahmaputra valley south with an

altitude ranging between 99 and 474 meters. A major part of it is and extensive plain

formed by the Brahmaputra and its major south bank tributary –the Buri-Dihing. Being

located on the north of the 270N latitude and with its unique physiographic elements, the

area experiences subtropical monsoon climate with mild winter, warm and humid

summer. Rainfall decreases from south to north and east to west in the area. The

average annual rainfall of the Dibrugarh city in the north is 276 cm with a total number

of 193 rainy days, while at Naharkatia in the south; it is 163 cm with 147 rainy days.

The temperature generally decreases from south to north. The average annual

temperature in Dibrugarh and Naharkatia is 23.90C and 24.30C respectively.

There are 139 tea estates in Dibrugarh district which covered the area of 120489

Hectares land. Besides these tea estates, there are 104 registered small tea growers and

6530 small tea growers, which covering the 11798 Hectares land.

In the plains of Dibrugarh and Sivasagar districts, the soil is Alluvial. The soil in

adjacent to the river banks is sandy and away from the bank is muddy. The main crops

grown in this district are tea and rice. Tea is the most important cultivation in this area.

The districts are the largest producer of tea in Assam (about 70% of the total

production). The productivity of tea is about 1850 kg per hectare. The tea estates which

are selected for studies (Figure 1) are

(1)Sepon tea estate: 27007.105/ N and 0940 50.466/ E

(2) Moran tea estate: 27007.391/ N and 094052.943/E

(3) Doomar Dullung tea estate: 27007.609/N and 094052.903/ E

(4) Hingrijan tea estate: 27008.618/ N and 094056.628/ E

(5) Khumtai tea estate: 27009.548/ N and 094056.236/ E



(6) Teloijan tea estate: 27013.596/ N and 094057.759/ E

(7) Thowra tea estate: 27007.222/ N and 094049.922/ E

(8) Mahkhooti tea estate: 27006.498/ N and 094048.459/ E

(9) Maskara tea estate: 27007.298/ N and 094043.647/ E

(10) Rajmai tea estate: 27005.975/ N and 094042.789/ E

(11)Amarawati tea estate: 27016.276/ N and 094055.761/E

(12)Borboruah tea estate: 27024.554/N and 094053.237/E

(13)Bamunbari tea estate: 27014.415/ N and 094059.018/ E

(14)Khowang tea estate: 27014.936/N and 094053.311/E

(15)Duliabam tea estate: 27016.364/N and 094055.277/E

(16) Diksam tea estate: 27012.710/N and 095001.684/E

(17)Ghoorania tea estate: 27021.378/N and 094052.188/E

(18)Durgapur tea estate: 27023.506/N and 094052.443/E

(19) Dirai tea estate: 27012.070/ N and 095002.030/ E

(20)Lepetkata tea estate: 27022.649/N and 094052.139/E

A total of 60 surface soil samples (0-15) cm, corresponding 60 subsurface (I) soil

samples (15-30) cm and 60 subsurface (II) soil samples (30-60) cm were collected from

the different area of the twenty tea estates. Soil samples were collected every year at the

same time, in the months of January and February, because no fertilization or compost

was applied during these months in the tea estates. Soil control sample was equally

collected from the nearby the tea estate area with no fertilization.

The collection of soil samples is done by using a soil auger. Several samples are

collected from a single station from three grids (7×10 m) within each field and these are

then mixed together to obtain a composite representative samples.

The effective size reduction was done by coning and quartering method. Preliminary

treatment of the soil samples after collection, preservation and analysis are carried out

by following standard procedures [35], [10], [30].

The total organic matter was estimated by Walkley-Black method [78]. For heavy

metals, about 1g of the sieved air dried soil samples were transferred to 100 ml

beaker. A triacid mixture [63] about 25-30 ml consisting of Conc.H2SO4, Conc. HCl

and Conc. HNO3 in the ratio of 4:2:1 was added to each beaker.The mixture was heated

on a hot plate gently at first and then more strongly until white fumes were no longer



evolved. The digested soil was treated with hot dilute HCl (1:1) and kept overnight and

filtered through a Whatman No 42 filter paper and washed several times with distilled

water.The filtrates were diluted so as to get an adequate volume of solution for analysis.

The dilution factor was noted. The digested extracts were then analyzed for the

concentration of heavy metals (Cd, Cr, Cu, Fe, Pb, Mn, Ni and Zn) by atomic

absorption spectrophotometer (Varian Spectra 220).

Result and Discussion:The experimental results of the analysis at three depths (0-15)

cm, 15-30) cm and (30-60) cm are presented in table 1 to 11 for the tea estate soils.

Table 1. Total organic carbon content (%)

Table 2. Cadmium content (mg/kg) of

of the soil samples at three depths.

the soil samples at three depths. Sample Surface Subsurface I Subsurface II

Sample Surface Subsurface I Subsurface II

1 2.3 1.52 1.2 1 2.19 1.9 1.83 2 2.81 1.53 1.48 2 2.48 2.3 2.29 3 2.8 1.98 1.65 3 2.4 2.25 2.14 4 2.72 1.9 1.61 4 2.31 2.11 1.97 5 2.22 1.49 1.12 5 2.11 1.86 1.71 6 2.07 1.31 0.97 6 1.78 1.57 1.44 7 3.05 2.27 1.92 7 2.73 2.51 2.47 8 3.23 2.41 2.11 8 2.82 2.69 2.61 9 2.02 1.28 0.96 9 1.65 1.51 1.4

10 2.97 2.14 1.81 10 2.67 2.45 2.4 11 2.16 1.47 1.09 11 2.06 1.79 1.62 12 3.6 2.81 2.46 12 2.83 2.8 2.69 13 1.91 1.27 0.9 13 1.61 1.43 1.26 14 3.21 2.4 2.08 14 2.8 2.59 2.54 15 2.96 2.14 1.71 15 2.57 2.38 2.33 16 1.87 1.19 0.88 16 1.52 1.28 1.19 17 2.64 1.85 1.54 17 2.27 2.06 1.87 18 2.12 1.4 1 18 1.86 1.66 1.5 19 2.15 1.44 1.02 19 1.98 1.76 1.56 20 2.76 1.96 1.63 20 2.35 2.16 2.06

Control 1.34 1.2 0.8 Control 1.42 1.06 0.96 Values are means of three measurements. Values are means of three measurements.

The percentage of total organic matter ranged from 1.87 to 3.60%, 1.19 to 2.81% and

0.88 to 2.46% for the surface, subsurface (I) and subsurface (II) soil respectively. The

organic carbon of the soil samples were higher in tea estate soil, this may be due to



addition of fertilizers, animal wastes, tea leaves and branches into the soil. The

percentage of organic carbon decreased as soil depth increased. Similar evidences have

been reported by many researchers [8] that organic carbon was more in the top soils and

decreased as depth increased. It was found that the percentage of total organic matter of

the tea estate soil increases during the study period from 2007 to 2009.

Table3. Chromium content (mg/kg) of Table4. Total copper content of the soil soil samples at three depths. samples at three depths. Sample Surface Subsurface I Subsurface II

Sample Surface Subsurface I Subsurface II

1 82.42 72.92 63.7 1 24.12 20.6 17.2 2 91.9 82.43 74.07 2 27.89 23.83 21.23 3 90.53 80.53 72.5 3 27.4 23.17 20.03 4 86.38 76.33 68.17 4 25.97 22.23 18.88 5 80.92 70.83 61.57 5 23.93 20.37 16.93 6 74.58 63.97 54 6 21.5 17.33 14.53 7 96.93 89.13 82.4 7 30.77 27.53 24.6 8 99.8 92.67 87.77 8 34.52 29.9 26.83 9 72.18 60.38 50.38 9 19.93 16.4 13.9

10 95.28 87.9 80.53 10 30.03 26.73 23 11 79.83 68.5 59.03 11 23.5 19.87 16.27 12 102.02 94.07 88.93 12 36.33 31.73 29.13 13 70.97 58.3 48.83 13 18.67 15.77 13.43 14 98.3 91.1 84.87 14 31.9 28.07 25.33 15 93.6 85.83 78.13 15 28.85 25.23 22.07 16 68.73 56 46.58 16 16.73 15.35 13.17 17 84.5 75.03 66.13 17 25.03 21.83 17.9 18 76.23 64 55.5 18 22.57 19.13 15.27 19 78.1 66.47 56.72 19 23.2 19.77 15.87 20 88.37 78.37 71.07 20 26.75 22.93 19.33

Control 42.2 34.6 28.4 Control 12.8 10.5 8.4 Values are means of three measurements.

Values are means of three measurements.

The concentration of Cd, Cr, Cu, Fe, Pb, Mn, Ni and Zn were varied from 1.52 to 2.83,

1.28 to 2.80 and 1.19 to 2.69 mg/kg; 68.73 to 102.02, 56.0 to 94.07 and 46.58 to 88.93

mg/kg; 16.73 to 36.33, 15.35 to 31.73 and 13.17 to 29.13 mg/kg; 4.933 to 10.766, 4.405

to 9.962 and 3.206 to 8.531 mg/g; 25.17 to 52.88, 20.17 to 41.67 and 16.97 to 33.70

mg/kg; 118.53 to 420.53, 103.73 to 390.33 and 92.07 to 377.50 mg/kg; 34.40 to 65.37,

30.67 to 60.00 and 19.13 to 46.27 mg/kg and 21.43 to 65.20, 21.07 to 56.47 and 17.70

to 48.87 mg/kg for the surface, subsurface (I) and subsurface (II) soil respectively.



The heavy metals fraction of the soil showed largest variation from metal to metal and

tea estate to tea estate. The heavy metals can enter the soil by a number of pathways and

their behaviors and fate in soils differ according to their sources and species. Once

heavy metals are introduced into the soil they accumulate in the soil system.

Table 5. Iron content (mg/g) of the soil Table 6. Manganese content(mg/kg) of the samples at three depths. soil samples at three depths. Sample Surface Subsurface I Subsurface II Sample Surface Subsurface I Subsurface II

1 7.475 6.6 5.115 1 260.33 238.63 210.13 2 9.366 8.436 6.964 2 333.2 307.93 277.73 3 8.952 8.069 6.625 3 318.5 288.63 267.93 4 8.108 7.194 5.705 4 288.73 260.27 235.4 5 7.194 6.352 4.897 5 245.93 223.53 197.8 6 6.051 5.182 3.687 6 174 157 144.2 7 10.232 9.281 7.808 7 373.7 357.4 328.73 8 10.632 9.775 8.358 8 404.6 383.6 356.8 9 5.582 4.623 3.533 9 153.4 144.8 123.3

10 9.975 9.122 7.636 10 360 349.53 310.87 11 6.808 5.963 4.521 11 230.67 207.3 185.6 12 10.766 9.962 8.531 12 420.53 390.33 377.5 13 5.197 4.415 3.287 13 138.07 120.3 101.8 14 10.485 9.592 8.138 14 390.13 373.13 343.07 15 9.755 8.86 7.407 15 347.33 322.8 290.47 16 4.933 4.405 3.206 16 118.53 103.73 92.07 17 7.809 6.945 5.404 17 274.07 248.3 225.3 18 6.437 5.579 4.116 18 196.1 183 158.8 19 6.56 5.605 4.156 19 215.23 191.57 171.53 20 8.615 7.715 6.275 20 302.47 276.27 247.07



The content of solid-phase humic substances is greatly affecting the adsorption capacity

for heavy metals by cation exchange and formation of chelate complexes. Carboxy

groups play a predominant role in metal binding in both humic and fulvic acid [3].

Presence of dissolved organic matter, may, on the contrary, also decrease heavy metal

adsorption, as found for copper by some workers [51]. It was investigated that the

sorption of heavy metals (including Cu, Cr, Pb and Zn) to humic acid at different pH

values and found that Pb was adsorbed to the highest extent in the pH range 2.4 to 5.8

and Zn to the least extent [72]. The influence from organic matter on the overall

adsorption is dependent on the actual heavy metal [57]. Different mechanisms are



responsible for the adsorption and retention of heavy metals in polluted soils such as

specific adsorption, cation exchange capacity, organic complexation and co-

precipitation [2], [3]. The affinity of different heavy metals for adsorption to different

soil particles is a highly complex

Table 7. Nickel content(mg/kg) of the soil Table 8. Lead content (mg/kg) of the soil samples at three depths. samples at three depths. Sample Surface Subsurface I Subsurface II Sample Surface Subsurface I Subsurface II

1 49.63 44.43 33 1 36.77 29.4 24.83 2 57.9 45.13 38.3 2 44.08 30.07 28.7 3 56.6 48.07 37.2 3 42.17 33.78 28.2 4 52.8 46 35.43 4 39.77 31.77 26.82 5 48.7 43.27 31.8 5 35.98 28.05 23.97 6 43.1 37.07 27.4 6 30.58 24 20.23 7 61.1 51.83 41.63 7 47.85 37.8 30.93 8 63.67 55.27 44.47 8 50.9 40.55 32.97 9 40.43 36.13 25.33 9 28.4 22.73 19.23

10 60.07 50.77 40.53 10 46.73 36.87 30.33 11 46.93 41.93 31 11 34.97 27.03 23.13 12 65.37 60 46.27 12 52.88 41.67 33.7 13 36.9 33 22.5 13 26.67 20.95 17.83 14 62.5 53.07 43.03 14 49.22 38.5 31.97 15 59.13 49.73 39.3 15 45.4 36 29.6 16 34.4 30.67 19.13 16 25.17 20.17 16.97 17 51.33 45.33 34.6 17 38.53 30.52 25.83 18 44.9 39.67 28.93 18 32.22 25.03 21.13 19 45.87 41 30.27 19 34.02 25.95 22.6 20 55.1 46.97 36.5 20 41.28 32.53 27.53



matter [57]. Lead adsorbed to a high extent as the only heavy metal to iron oxides,

whereas, e.g., Cd, Cr, Cu, Ni, Pb and Zn all adsorbed to vermiculite in a study of

different heavy metals to individual soil components [19]. Uptake of Cadmium depends

upon the content of Zinc in the soil, and plants generally take up more Cadmium if Zinc

content is low [41]. The retention of heavy metals in a specific soil depends on the soil

composition as well as on the actual heavy metal [57]. It was also investigated the

relation between pH and Zn solubility in spiked acid and calcareous soils [68]. Zinc was

solubilised at a slightly higher pH in the calcareous soils than in the acid soils [47].

Lead and nickel occur at the highest concentrations, usually near the roadsides,



associated with Zinc and Cadmium [14], their amounts decrease with increasing

distances from the road and with increasing depth in soil [59], [76].

Table 9. Zinc content (mg/kg) of the soil samples at three depths. Sample Surface Subsurface I Subsurface II

1 41.97 39.53 29.83 2 51 49.27 37.93 3 47.8 46.27 36.3 4 45.53 43.53 33.3 5 40.57 37.83 27.73 6 33.03 30.07 22.93 7 58.27 52.13 41.73 8 62.8 55.07 46.4 9 30.9 27.17 20.8

10 55.77 50.73 40.27 11 38.4 36.37 26.6 12 65.2 56.47 48.87 13 25.57 22.67 19.47 14 60.43 53.5 44.2 15 52.87 50.1 39 16 21.43 21.07 17.7 17 44.23 41.57 31.77 18 34.97 31.47 23.9 19 37.1 34.33 25.47 20 46.6 44.6 34.8

Control 20.82 18.68 16.9 Values are means of three measurements.

Table 10. Probable background levels and typical concentration of some heavy metals in soils

Heavy Background Typical metal

concentration(mg/kg) concentration (mg/kg)

Cd 0.1 to 40 0.1 to 50 Cr 80 to 200 5 to 1500 Cu 6 to 60

2 to 250

Ni 1 to 100

2 to 1000 Pb 12 to 20 2 to 300 Zn 17 to 125 10 to 300

Source: [14],[6], [33] [2],[47]



Table 11. Maximum and minimum measured values of heavy metals contents(mg/kg) of soils

Sample Measured limits Cd Cr Cu Fe(mg/g) Mn Ni Pb Zn 1 Max.

2.19 82.42 24.12 7.475 260.33 49.63 36.77 41.97

Min.

1.83 63.7 17.2 5.115 210.13 33 24.83 29.83

2 Max. 2.48 91.9 27.89 9.366 333.2 57.9 44.08 51

Min.

2.29 74.07 21.23 6.964 277.73 38.3 28.7 37.93

3 Max.

2.4 90.53 27.4 8.952 318.5 56.6 42.17 47.8

Min.

2.14 72.5 20.03 6.625 267.93 37.2 28.2 36.3

4 Max. 2.31 86.38 25.97 8.108 288.73 52.8 39.77 45.53

Min.

1.97 68.17 18.88 5.705 235.4 35.43 26.82 33.3

5 Max.

2.11 80.92 23.93 7.194 245.93 48.7 35.98 40.57

Min.

1.71 61.57 16.93 4.897 197.8 31.8 23.97 27.73

6 Max. 1.78 74.58 21.5 6.051 174 43.1 30.58 33.03

Min.

1.44 54 14.53 3.687 144.2 27.4 20.23 22.93

7 Max.

2.73 96.93 30.77 10.232 373.7 61.1 47.85 58.27

Min.

2.47 82.4 24.6 7.808 328.73 41.63 30.93 41.73

8 Max. 2.82 99.8 34.52 10.632 404.6 63.67 50.9 62.8

Min.

2.61 87.77 26.83 8.358 356.8 44.47 32.97 46.4

9 Max.

1.65 72.18 19.93 5.582 153.4 40.43 28.4 30.9

Min.

1.4 50.38 13.9 3.533 123.3 25.33 19.23 20.8

10 Max. 2.67 95.28 30.03 9.975 360 60.07 46.73 55.77

Min.

2.4 80.53 23 7.636 310.87 40.53 30.33 40.27

11 Max.

2.06 79.83 23.5 6.808 230.67 46.93 34.97 38.4

Min.

1.62 59.03 16.27 4.521 185.6 31 23.13 26.6

12 Max. 2.83 102 36.33 10.766 420.53 65.37 52.88 65.2 Min. 2.69 88.93 29.13 8.531 377.5 46.27 33.7 48.87

13 Max.

1.61 70.97 18.67 5.197 138.07 36.9 26.67 25.57

Min.

1.26 48.83 13.43 3.287 101.8 22.5 17.83 19.47

14 Max. 2.8 98.3 31.9 10.485 390.13 62.5 49.22 60.43

Min.

2.54 84.87 25.33 8.138 343.07 43.03 31.97 44.2

15 Max.

2.57 93.6 28.85 9.755 347.33 59.13 45.4 52.87

Min.

2.33 78.13 22.07 7.407 290.47 39.3 29.6 39

16 Max. 1.52 68.73 16.73 4.933 118.53 34.4 25.17 21.43

Min.

1.19 46.58 13.17 3.206 92.07 19.13 16.97 17.7

17 Max.

2.27 84.5 25.03 7.809 274.07 51.33 38.53 44.23

Min.

1.87 66.13 17.9 5.404 225.3 34.6 25.83 31.77

18 Max. 1.86 76.23 22.57 6.437 196.1 44.9 32.22 34.97

Min.

1.5 55.5 15.27 4.116 158.8 28.93 21.13 23.9

19 Max.

1.98 78.1 23.2 6.56 215.23 45.87 34.02 37.1

Min.

1.56 56.72 15.87 4.156 171.53 30.27 22.6 25.47

20 Max. 2.35 88.37 26.75 8.615 302.47 55.1 41.28 46.6

Min.

2.06 71.07 19.33 6.275 247.07 36.5 27.53 34.8

Control Max.

1.42 42-2 12.8 4.052 98.04 26.54 20.34 20.82 Min. 0.96 28.4 8.4 3.022 78.8 23.8 17.12 16.9



Table12 Range of concentration of heavy metals in some fertilizers and lime materials in mg/kg.

Elements N a P b NPK b Lime a Cd .05—8.5 0.1--170 1--10 0.1—24 Cr 0.3—2.9 66--245 20--72 10—15 Cu 1--15 1--300 4--38 2—125 Ni 7--34 7--38 9--20 10—20 Pb 2--27 7--225 10--130 20—250 Zn 1--42 50--1450 22--350 10--450

a= [39] b=[29] If the contaminats are bound strongly to the soil and their desorption does not occur,

ground water pollution may not be a problem. On the other hand, if desorption takes

place easily, the contaminants could become mobile and contaminate water supplies.

The concentration of heavy metals Cd, Cr, Cu, Fe, Pb, Mn, Ni and Zn increases with

increase in organic matter content in the soil [80] The soil samples showing high levels

of heavy metal concentration had high organic matter content. A complexation reaction

occurs between heavy metals and organic matter content and results in the retention of

heavy metal in the soil [50], [44]. Increase in pH in the soil results in increase heavy

metal concentration in the soil. Even though the higher pH favors the heavy metal

retention in soil, it limits the heavy metal uptake by plants. The heavy metal uptake by

plants decreases as the pH value increases. The acidic pH favors the uptake and causes

harmful effect to the living beings through the food chain. The pH value of the tea estate

soil was found to be acidic. This indicates that the uptake by plants was high and the

biological system was contaminated by the heavy metals. Soil pH and high total organic

matter content have a higher retention capacity of heavy metal in soil. The present

studies agree with the findings of workers [81], [8] ,[80]. All the heavy metals

decreased in concentration as soil depth increased. It was found that the concentration of

heavy metals of the tea estate soil increases during the study period.

According to the following workers [73], [22] a good correlation is predicted if the

linear regression co-efficient “r” is ≥ .7. A positive and significant correlation between

total organic matter and available heavy metals Cd to Zn are 0.95, 0.96, 0.96, 0.96, 0.97,

0.96, 0.96 and 0.96 respectively.



The movement of heavy metals within a region is influenced by wind, water and

gravity. The movement of heavy metals within the soil mass will be principally in the

solution phase [17]. The movement of heavy metal or potentially toxic element in the

soil is of concern due to potential impact on the environment through contamination of

ground water by leaching.

The degree of soil pollution by heavy metals from various anthropogenic activities, such

as application of inorganic fertilizers, animal wastes and pesticides [38], [54]. A large

amount of heavy metals enrich in the tea estates soil by fertilizers. The range of

concentration of heavy metals in some fertilizers and lime material in mg/kg is given in

the table 12 [29], [47].

Conclusion The results indicate that the soil had slightly increasing trends of heavy metal

concentration but still within tolerable levels. However, the obtained mean values of

heavy metals in the study sites are higher that found in the control site.Among these

heavy metals Ni, Cr, Pb and Cd are soil pollutants and Cu, Zn, Mn and Fe, and are

known as micronutrients or trace elements as these are required in small quantities. The

micronutrient elements in minute quantities produce optimum effects. On the other

hand, even a slight deficiency or excess is harmful to the plants. By the application of

fertilizers, animal wastes and fungicides into the soil not only supply the essential

nutrients but also enrich the soil with the heavy metals. These are capable of interfering

with biological activities, persistent toxicants within ecosystems and create acute health

hazards for humans, animals and plant kingdoms. Therefore, there is a need for

optimization of fertilizers, animal wastes and fungicides for improvement of the soil

productivity without creating environmental problems.



References :

[1] Adriano , D.C. (2001). Trace elements in the terrestrial environment: biogeochemistry, bioavailability and risk of metals, 2nd edn. New York: Springer.

[2] Alloway, B.J. (1990). Heavy Metals in soils. Blackie, London. [3] Alloway, B.J. (1995). Soil processes and the behaviour of heavy metals. In

B.J.Alloway (Ed.), Heavy metals in soils. London: Blackie Academic and Professional.

[4] Arendit, F., Hinsenveld, M and Van Brink, (1990). In: Contaminated Soil, Kluwer Academiv, Dordrecth. The Netherlands.

[5] Balsberg-Pahlsson, A.M., Lithner, G and Tyler, G.(1982). Krom i iljon,Statens Naturvardsverk Rapport SNV pm 1570, Solna, Sweden ( in Swedish)

[6] Benerji,S.K.( 2007). Environmental Chemistry, second edition, Prentice-Hall of India Private Limited, New Delhi.

[7] Bansal, R.L., Nayar, V.K and Takkar, P.N. 1992). Accumulation and bioactivity of Zn, Cu, Mn and Fe in soil polluted with industrial waste water, Journal of the Indian Society of soil Science, 40 (4): 796-799.

[8] Bansal, O.P. (2004). Uptake of heavy metals by crops plants, Poll Res. 23 (3): 501-506.

[9] Bargagli, R.( 1998). Trace elements in terrestrial plants. An ecophysiological approach to biomonitoring and biorecovery, pp 324. Berlin, Springo. [10] Baruah, T.C. and Borthakur, H.P.(1997) In: A textbook of soil chemical

analysis, Vikash Publishing, New Delhi. [11] Bowen,H.J.M.(1979). Environmental chemistry of the Elements. Academic

Press,Troy, MO. [12] Bradham, K.D., Daylon, E.A., Basta, N.T., Schroder, J., Payton, M. and

Lanno,R.P. (2006). Effect of soil properties on lead bioavailability and toxicity to earth-worms. Environmental Toxicology and Chemistry, 25, 769-775.

[13] Brandt, K.K., Holm, P.E. and Nybroe, O. (2006). Bioavalability and toxicity of soil particle-associated copper as determined by two bioluminescent. Pseudomonas fluorescence biosensors strain, Environmental Toxicology and Chemistry, 25, 1738-1741.

[14] Bretzel, F. and Calderisi, M. ( 2006).Metal contamination in urban soils of coastal Tuscahy (Italy). Environmental Monitoring and Assessment, 118, 319-335.

[15] Brooks, R.R.( 1998). Plants that hyperaccumulate heavy metals, pp 289-312. Wallingford: CAB International.

[16] Caussy, D. , Gochfeld, M. , Gurzau, E. , Neagu,C. and Ruedel, H. ( 2003). Lessons for case studies of metals: investigating exposure,bioavailability and risk.Ecotoxicology and Environmental Safety, 56, 45-51.

[17] Chitdeswari ,T and Jegadeswari, D. (2007), Hazardous Issues of Heavy metals to Ecosystem and Humah Health. Pollution Management. Pointer Publishers, Jaipur (Raj) India, pp 77-8 6

[18] Chakraborty, Rahul., Dey, Sudip., Dkhar, S., P,Tibah., R.C, Myrboh.,B, Ghosh., and Sharma,D.K.(2004).Determination of few heavy metals in some vegetables fromNorth Eastern Region of India in relation to Human Health. Poll.Res. 23(3):537-547).



[19] Covelo, E.F., Vega, F.A and Andrade,M.L. ( 2007). Competitive sorption and desorption of heavy metals by individual soil components. Journal of Hazardous Materials, 140, 308-315.

[20] Cui, Y. , Zhu, Y.G. , Zhai, R. , Huang, Y. , Qiu, Y. and Liang, J. ( 2005). Exposure to metal mixture s and humans health impacts in a contaminated area in Nanning, China.Environment International, 31, 784-790.

[21] Cunningham, S.D. , Berti, W.R. and Huang, J.W. (1995). Phytoremediation of contaminated soils. Trends in Biotechnology, 13, 393-397.

[22] Das Gupta, Adak. M. and Purohit, K.M. ( 2000). Correlationcoefficients of some physicochemical characteristics of surface and ground water on Rajgangpur. Part-1,Indian,J.Environ. Protec. 20 (9) : 681-687.

[23] Douay, F. , Roussel, H. , Pruvot, C. , Loriette, A. and Fourrier, H. (2008).Assesment of a remediation technique using the replacement of contaminated soil in kitchen gardens nearby a former lead smelter in Northern France. The Science of the Total Environment, 401, 29-38.

[24] Dudka .S., Piotrowska .M and Terelak ,H (1996). Transfer of cadmium,lead and zinc from industrially contaminated soil to crop plants-A field study.Env. Poll, 94(2):181- 188.

[25] Erel, Y. and Morgan, J.J. (1992). The relationships between rock-derived lead and iron in natural fresh water symtems. eochemical et Cosmochimica Acta, 56,4157-4167.

[26] Fergusson, J.E. ( 1990). In: The heavy elements, chemistry, Environmental impact and health effects. Pregamon Press. Oxford.

[27] Galvex, F. ( 1998). ‘Rev. of Introduction to Metal Pollution by Kruus et al., 1991’ . Metal Pollution. Yhode Bookstocks Qh 545, pp 105-128.

[28] Granero, S. and Domingo, J.L. (2002).Levels of metals in soils of Aleada de Henares, Spain: Human health risks. Environment International, 28, 159-164.

[29] Gunnarsson, O.(1983). Heavy metals in fertilizers: Do they cause environmental and health problems. Fertlizers and Agriculturae 85: 27-42.

[30] Gupta.P.K. (2007). Method in Environmental analysis water,soil and air, Secod Edition, Agrobios(India)

[31] Halim, C.E., Scott,J.A., Amal, R., Short, S.A., Beydoum, D., Low, G. (2005). Evaluating the applicability of regulatory leaching tests for assessing the hazards of Pb- contaminated soils. Journal of Hazardous Materials, 120, 101-111.

[32] Hapke, H.J. (1991). Metal accumulation in the food chain and load of feed and food. In Meals and their compounds in the environment. E.Merian. VCH. NY. Pp 469-489.

[33] Hund-Rinke, K. and Kordel, W. (2003). Underlying issues in bio-accessibility and bioavailability, Ecotoxicology and Environmental Safety, 56,52-62.

[34] Ivask, A., Francois, M., Kahru, A., Dubourguir, H.C., Virta, M. and Douay, F.( 2004).Recombinant luminescent bacterial sensors for the measurement of bioavailability of cadmium and lead in soils polluted by metal smelters.

Chemosphere, 55, 147-156. [35] Jackson,M.L. (1973). Soil chemical analysis. Prentice Hall of India Private Ltd,

New Delhi Jacob.C and Joseph,P.V,2008, Study of heavy meyal levels in the soils of Pala Municipality, Kerala. Poll.RES. 27(2) :279-283.

[36] Jacob, C. and Joseph, P.V. (1994). Study of heavy metal levels in the soils of

Pala Municipality, Kerala. Poll. Res. 27 (2): 279-283.



[37] Janssen, R.P.T., Posthuma, L.,Baerselman, R. and Den Hollander, H.A.( 1997). Equilibrium partitioning to heavy metals in Dutch field soils.II. Prediction of

metal accumulation in earth-worms.Environmental Toxicology and Chemistry, 16, 2479-2488.

[38] Jeevan Rao. (1998). Heavy metal inputs to soil by agricultural activities. Env. Geochemistry.1:15-18.

[39] Kabata-Pendias, A and Pendias, A. 1984).Trace Elements in soils and plants. CRC Press,Boca Raton, Fla.

[40] Kanwar, J.S. ( 1977). Int. Sym. Soil fert. Evaluation. Proceedings, Vol. 1, pp 1103-1113.

[41] Kirkham, M.B. (2006). Cadmium in plants on polluted soils: Effects of soil actors,hyperaccumulation, and amendments, Geoderma, 137, 19-32.

[42] Klein, H., Priebe, A. and Jaeger, H.J. (1981). Greuzen der Beastbarkeit von Kulturpflanzen mit dem Schwermetall Cadmium, Angewandle Botanik 55, 295-308.

[43] Li, Z. and Shuman, L.M. (1996). Heavy metal movement in metal contaminated soil profiles. Soil Sci. 161, 656-666.

[44] Kumari T.K, Rao, B.M and Ranganavakulu,N. (2001).Characterzation and Distribution of cationic micronutrients in typical soil profile of Tirumala Hills. IJEP 21(9) pp 847-849.

[45] Magrisso, S., Belkin, S., Erel, Y. (2009). Lead Bioavailability in Soil and Soil Components, Water Air Soil Pollution, 202: 315-323.

[46] Mantovi, P. , Baldoni, G. and Toderi, G. (2005). Reuse of liquid, dewatered, and composted sewage sludge on agricultural land: effects of long-term application on soil and crop. Water Research, 39, 289-296.

[47] Martinez, C.E. and Motto, H.L. (2000).Solubility of lead , zinc and copper added to mineral soils. Environmental Pollution, 107, 153-158.

[48] Mbila, M.O. , Thompson, M.L. , Mbagwu, J.S.C. and Laird, D.A. (2001). Distribution and movement of sludge derived trace metal in selected Nigerian Soils. Journal of Environmental Quality, 30,1667-1674).

[49] McBride, M.B. (2003). Toxic metals in sewage sludge- amended soils: has promotion of beneficial use discounted the risk. Advances in Environmental Research, 8, 5-19.

[50] McLaren, R.G. and Crawford, D.V. (1973) Studies on soil copper. The fractionation of copper in soils. J. Soil. Sci. 24, 172-181.

[51] Mesquita,M.E. and Carranca, C. (2005). Effects of dissolved organic matter on copper zinc competitive adsorption by a sandy soil at different pH values. Environmental Technology, 26(9), 1065-1072.

[52] Migeon, A. , Guinet, F. , Chalol, M. and Blaudez, D. ( 2009). Metal

Accumulation by woody species on contaminated sites in the North of France. Water Air Soil Pollution, 204, 89-101.

[53] Motsana, M.R. and Joginder Singh. (1981) Indian Fmg., 31: 3-12. Mulligan, C.N. ,Young, R.N. and Gibbs, B.F. (2001). Remediation Technologies for metal- contaminated soils and groundwater. An evaluation, Engineering Geology. 60, 193-207.

[54] Narasimbha Rao,S.L and Sharma, D.R.R.(1998). Trace metalsin soil near an industrial belt in Visakhapatram, Poll. Res. 7(4):377-380.



[55] Nriagu,J.O. (1991). Human influence on the global cycling of trace metals.In heavy metals in the environment (vol 1), Ed J.G.Farmer. CEP consultants Ltd, Edinburgh, U.K. pp 1-5.

[56] Oliveria, F.C. , Mattiazzo, M.E. ,Marciano, C.R. and Abreu Junior, C.H. (2002). Movement of heavy metals in an Oxisol fertilized with municipal solid waste compost. Pesquisa, Agropequria Bersileira, 37 (12),1787-1793).

[57] Ottosen,L.M., Hasnsen, H.K. and Jensen, P.E. ( 2009). Relation between pH and Desorption of Cu, Cr, Zn and Pb from Industrially Polluted Soils. Water, Air Soil Pollution, 201: 295- 304.

[58] Paramasivam, S. , Sajwan, K.S. and Alva, A.K. (2006). Incinerated sewage sludge products as amendments for agricultural soil: leaching and plant uptake of trace elements. Water, Air and Soil Pollution, 171 (1-4), 273- 290.

[59] Paterson, E., Sanka, M. and Clark, L. (1996). Urban soils as pollutant sink- a case study from Aberdeen, Scotland. Applied Geochemistry, II, 129-131.

[60] Peijnenburg, W.J.G.M. ( 2002).Bioavailability of metal to soil in verbrates. In H.E. Allen (Ed.), bioavailability of metals in terrestrial ecosystems: importance of artitioning for bioavailability to inverbrates, microbes, and plants. Pp 89-112. Pensacola: SETAC.

[61] Peijnenburg, W.J.G.M., Baerselmen, R.,de Groot, A.C., Jager, T., Posthuma, L. and Van Veen,R.P.M. ( 1999). Relating environmental availability to bioavailability: Soil-type dependent metal accumulation in the Oligochaete Eiseniandei, Ecotoxicology and Environmental Safety, 44, 294-310.

[62] Piotrowska, M. and Dudka, S .(1994). Estimation of maximum ermissible levels of cadmium in a light soil by using cereal plants. Water, Air and Soil Poll., 73 (1-4) : 179-188.

[63] Pinta, M. ( 1975). Detection and determination of trace elements, ANA, Arbor Science Publication INC.

[64] Pruvot, C. ,Douay, F. , Herve, F. , and Waterlot, C. (2006). Heavy metals in soil, crops and grass as a source of human exposure in the former mining area. Journal of Soils and Sediments, 6, 215-220.

[75] Rensing, C. and Maiver, R.M. (2003). Issues underlying use of biosensors to measure metal bioavailability. Ecotoxicology and Environmental Safety, 56, 140-147.

[66] Robson, M. (2003). Methodologies for assessing exposure to metals: human host factor. Ecotoxicology and Environmental Safety, 56, 104-109.

[67] Rodney, R., Piepenbrink, D.S. and Piepenbrink, M.S.(2006). Lead and immune function. Critical Reviews in Toxicology, 36, 359-385.

[68] Saeed,M. and Fox, R.L. (1977). Relation between suspension pH and Zn solubility in acid and calcareous soils. Soil Science, 124, 199-204.

[69] Salt, D.E. , Smith, R.D. and Raskin, I.(1998). Phytoremediation. Annual Review of Plant Physiology and Plant Molecular Biology, 49, 643-668.

[70] Sanchez-Monedero, M.A. , Mondini, C.de Nobile, M. , Reita, L. and Roig, A. (2004). Land application of biosolids. Soil response to different stabilization degree of the treated organic matter, Waste Management, 244, 325-332.

[71] Sauve, S. (2002). Speciation of metals in soils. In H.A.Alle (Ed.), bioavailability of metal in terrestrial ecosystem: importance of partitioning for bioavailability to invertebrates, microbes, and plants, pp 7-37, Pesacola: SETAC.

[72] Schnitzer, M. and Kerndorff, H. (1980). Effects of pollution on humic



substances. Environ Sci Health B,15(4), 431-456. [73] Singanan, M.K., Somasekhara and Rambabu.(1995). A correlation study on

physicochemical characteristics of ground water in Rameswaram Island. Indian J. Environ. Protec. 15 (3) : 213-217.

[74] Stabnikova, O. , Goh, W.K. , Ding, H.B. , Tay, J.H. and Wang, J.Y. ( 2005). The use of sewage sludge and horticultural waste to develop artificial soil for plant cultivation in Singapore. Bioresearch Technology, 96(9); 1073-1080).

[75] Su, D.C. and Wong, J.W.C.( 2003).Chemical speciation and phytoavailability of Zn, Cu, Ni and Cd in soil amended with fly ash- stabilized sewage sludge. Environment International, 29, 895-900.

[76] Sutherland, R.A. and Tolosa, C.A. (2001). Variation in total and extractable elements with distance from roads in an urban watershed, Honolulu, Hawaii. Water, Air and Soil Pollution, 127, 315-338.

[77] Udom, B.E. , Mbagwu, J.S. ,Andesodun, J.K. and Agbim, N.N. (2004).Distribution of Zn,Cu, Pb and Cd in a topical ultisol after long-term disposal of sewage sludge.Environment International, 30 (4), 467-470.

[78] Walkey, A. and Black, C.A. (1974). Critical examination of rapid method of determining organic carbon in soil. Soil Sc. 63: 251-164.

[79] Wang, M.J. ( 1997). Land application of sewage sludge in China. Science of the Total Environment, 197, 149-160.

[80] Wesley, S.G. ( 2004). Bioaccumulation of Heavy metals by the intertidal Molluscs of Konyakumari waters, Indian Pollution Research, 23(1): 37-40.

[81] William, C.H. and David. D.( 1976). Study on accumulation in soil of Cd residues from phosphate fertilizers and their effect on Cadmium content of plants. Soil Sci., 121: 86-93.

[82] Xing,G.X and Chen, H.M.(2004). Environmental impacts of metal and other inorganic on soil and ground water in China. Lewis publishers, Boca Raton, London, 167-200.

Date post:	23-Apr-2018
Category:	Documents
Upload:	halien
View:	225 times
Download:	0 times

HEAVY METALS CONTAMINATION OF TEA ESTATES … · heavy metals contamination of tea estates soil in...

Documents