MenuISSN (0970-2083)
ISSN (0970-2083)
D.C. Gupta
Dept. of Applied Geology, Barkatullah University, Bhopal, India
Visit for more related articles at Journal of Industrial Pollution Control
Risk characterization, Heavy metals, Carcinogenic risk
The area of present study is a part of Upper Betwa Basin situated around Mandideep industrial Complex (MIC). The area covers about 190 km on Survey of India toposhect no. 55 E/8 and 55 E/I2 and lie between latitude 22°04’ - 23°10’ N and longitude 77°25’ - 77°36’E in Obaidullaganj tehsil of Raisen district of Madhya Pradesh, India (Fig. 1). Geologically the area comprise Bhander sandstone of Upper Vindhyan age and lava flows of Deccan trap activity.
Figure 1: Location map of Mandideep Industrial area.
Two decades ago, Mandideep was a small village with 500 families and the main occupation oi the people was agriculture and animal husbandry. Due to presence of Betwa and Kaliasot rivers, Mandideep area, was known for good agriculture and lust green forest.
In 1981, this small village was proposed by Government of Madhya Pradesh to develop a well established industrial base close to the capital city of Bhopal. An area of about 2000 acres was chosen to host about 500 industries by the end of 7th five year plan. The present study, however, noticed that only 394 industries have been fully set up so far while others are coming up fastlysoon. These industries are manufacturing products like aerosols, pesticides, plastics, preservatives and automobiles discharging heavy load of untreated effluent through an open net work of drainage into perennial Betwa and Kaliasot rivers. A survey conducted in eight villages of Mandideep area reveal that surface water has become highly polluted, fertility of soil has reduced reduced and there occurs frequent death of cullies due to ingestion of contaminated surface water.
Risk characterization involves the quantitative estimation of the actual and potential risk and/or hazards due to exposure to each key chemical constituent and also the possible additive effects of exposure to the mixture of the chemicals of concern. The exposure estimate, the toxicity values used in the risk characterization should either be expressed both as absorbed doses or administered doses (intake). The present study the risk to potentially exposed populations from exposure and subsequent intake of the chemicals to potential receptors are characterized by the calculations of carcinogenic and non - carcinogenic hazards. In the present investigation ingestion exposures to various concentrations of trace metals like Cd, Cr, Fe, Ni, Pb and Sn in the surface waters are discussed in order to know the probability of carcinogenic risk to potential receptors.
A total of about 26 water samples were collected, representing 7 samples of Betwa River Water (BRW) and 6 from Kaliasot River Water (KRW) during pre and post monsoon season. These samples were collected as per the methodology suggested by Greenberg et al. (1981) for APHA, AWWA and WPCF. All samples were analyzed for trace elements like Cd, Cr, Fe, Ni, Pb, and Sn using Atomic Absorption Spectrophotometer model GBC - 902, made in Australia, at Regional Research Laboratory Bhopal. The degree of accuracy of the results were checked by preparing two standards having absorption similar to sample in the range of 0.4 μm to 0.6 μm respectively. Zero position is set by using the low standard and 1.00 position with high standard. The observed difference between these two standards is about 0.1 absorbency indicating the degree of accuracy of 0.1% to 0.2% of the results. The risk assessment study was carried out by using the equations given by CDHS (1986) ; USEPA (1989 a, 1989 b) ; and CAPCOA (1990) while carcinogenic risk is estimated after the equation given by USEPA (1989, i).
The trace elements concentration determined in surface water samples of pre monsoon season and post monsoon period for Betwa and Kaliasot River waters are given in Table 1. However, in Table 2 are given the concentration of various elements found above recommended limits after ISI : lO5OO.The Cd concentration found in 11 samples of BRW, varies from 0.005 ppm to 0.031 ppm with an average value of 0.013 ppm, while in rest Cd is Below Detectable Limit (BDL). In KRW Cd is found BDL in all the samples.
Table 1: Trace element concentrations in Betvva and Kaliasot river water samples of Mandideep industrial area during Pre and Post monsoon season
Table 2: Concnetration of trace elements exceeding recommended limits in Betwa and Kalaisot river water as per ISI: 10500 (1983)
The concentration of Cr occurs in 13 samples of BRW and it ranges from 0.004 ppm to 0.152 ppm with an average value of 0.084 ppm. The KRW on the other hand shows all values BDL for pre monsoon spell while in post monsoon samples, Cr found only in 3 samples viz. KRW-1, KRW-5 and KRW-6 and its concentration varies from 0.02 ppm to 0.04 ppm with an average value of 0.0067 ppm.
The Fe value in 12 samples of BRW ranges from 0.122 ppm to 3.69 ppm with a mean value of 0.794 ppm. Fe in KRW occurs only in 8 sample sites and its concentration varies from 0.101 ppm to 2.74 ppm with an average value of 0.659 ppm. Thus, Fe is found widely distributed in surface water samples of the area.
The Ni concentration in BRW varies from 0.003 ppm to 0.38 ppm with a mean value of 0.072 ppm. while in KRW, its value ranges from 0.015 ppm to 0.125 ppm and the average being 0.04 ppm. Pb and Sn are important carcinogens. The concentration of these two elements significantly varies from 0.115 ppm to 0.348 ppm and 0.84 ppm to 7.00 ppm in BRW with an average value of 0.187 ppm and 2.508 ppm respectively. However, in KRW Pb is found only at 4 samples sites and Sn occur only in 9 water samples and the concentration varies from 0.07 ppm to 0.082 ppm for Pb and 0.73 ppm to 1.02 ppm for Sn, with an average value of 0.026 ppm and 0.229 ppm respectively.
In the present investigation, the above elements are used for risk characterization and estimation of Carcinogenic Risk on the basis of available standards of absorbed doses through Gastrointestinal (Gl) tract.
Some of the heavy metals are considered essential both for plant and animal nutrition, and they served some useful biological functions in the body. Thus, Cu, Co, Mn, Mo, Se and Zn are essential to both plants and animals. However, some trace metals such as Cd, Hg, Pb and metalloids like As, Sb and Se are considered to have toxic, although sonic essential physiological roles have been inferred for As, Cd and I’b recently (Dura, 1993). Among the melals studied Cr, Ni, Cd und lie have been found to be potentially carcinogenic (i.e. causing cancer); Be, Cr and radionuclides such as Sr and 239Pu are potentially mutagenic ( i.e. causing chromosomal defects and altering genetic characteristics). Further, Cd, Cu, Pb, Hg, Mo, Ni and Se in excessive amount have been found to be potentially teratogenic (i.e. causing embryotoxic including anatomical birth defects). The heavy metal pollutants, on “acute exposure” or“chronic exposure”, severely affects different body organs and produces variety of diseases and deformities in the human body.
In order to work out surface water ingestion exposure for trace metals like Cd, Cr, Fe, Ni, Pb and Sn, an assessment study is conducted to estimate the magnitude of actual and/or potential human exposure, the frequency and duration of these exposures, and the pathways by which humans are potentially exposed to chemical from hazardous waste site. An exposure assessment phase of the health risk assessment involves the characterization of the physical and exposure setting. The pathway is the potential route, a contaminant take to reach potential receptor. The process is to estimate, the rate at which chemicals are absorbed by the organism through all mechanisms including ingestion, inhalation and dermal absorption. However, the route and duration of exposure greatly influence the impact on receptors.
In the present paper, an attempt has been made to work out the surface water ingestion exposure to available concentrations of Cd, Cr, Fe, Ni, Pb and Sn to a potential receptor through oral route only. The estimation of surface water exposure to Mandideep area is calculated by using the equation given by CDHS (1986) ; USEPA (1989a and 1989b) ; and CAPCOA (1990). These equations are based on the principle that the dose received by the potential receptor from ingestion will in general be dependent on the absorption of chemicals across the gastrointestinal (Gl) lining. However, the other standard parameters used in above calculation such as the value of water consumption rate, the average body weight for children 6-12 years and an adult, and the average life time exposure period for the above receptor has been considered after USEPA (1986 b); USEPA (1989a, 1989b, and 1989 c) ; USEPA (1988 a, 1989 b and 1989 c) respectively and the estimate based after site specific conditions (Asante - Duah, 1993). The standard GI absorption factor for cadmium is given by Heitanen (1981); Fleisher et al. (1974) ; Morgan et al. (1988) and Fergusson (1990).
The Gl factor for Cr, Fe and Sn is considered after Kannan (1995), while for Ni the value suggested by Dara (1993) and for Pb the GI factor suggested by O’Brien, 1979 ; Sayre, 1974 & 1981 ; Sheriock et al. 1982 and Fergusson (1990) are taken for the calculation of exposure assessment. The calculated values for water ingestion exposure to Betwa River Water and Kaliasot River Water are given in Table 3 both for children 6-12 years and to an adult along with average life time exposure for the same. In addition average whole life time exposure to an adult have also been calculated for potential receptors. It is mentioned here that Kaliasot river flows in the north, while Betwa river flows to the south of Mandideep Industrial Complex area. Because of the close proximity, most of the industries discharge their untreated effluent wastes into perennial Betwa river. The geological setting of Mandideep area reveal the presence of hard rock formations, in which the availability of ground water is scarce. Therefore, the people of the area are dependent on surface water resources for their domestic and irrigational needs.
Table 3: Wateringestion exposure of trace element concentrations found in Betwa and Kaliasot river waters to potential receptors in Mandideep industrial area
The occurrence of free metallic Cd in nature is rare. However, 52% of total Cd pollution comes from incineration or disposal of Cd bearing products like automobile tyres, motor oils, plastics and coal. Humans are exposed to Cd either through inhalation or by ingestion of contaminated food or drinks. Cd appears to be highly toxic because of the absence of homeostatic control of this metal in human body. Cd is readily absorbed through gastrointestinal lining, guts and lungs. The estimated daily intake of Cd ranges from 25 - 60 jig/day while Tolerance Dose Intake (TDI) is about 57-72 μg/day (Kannan, 1995).
Elementary absorption to Cd is affected by number of factors such as age, calcium, iron, zinc and protein deficiency (CEC, 1972, 1979 ; USEPA, 1980) and the chemical form of ingested Cd. However, dietary factors, such as Fe, Ca and protein deficiency, may increase the gastrointestinal absorption rate (Fiagan et al., 1978). In Fe deficient women, upto 20% of ingested Cd was found to be absorbed. The excessive amount of ingested Cd replaces Zn al key enzyme sites and induced metabolic disorder. The pulmonary absorption however, depends on the size and the solubility of the particles containing Cd. Absorbed Cd will enter the blood stream and become concentrated in certain parts of the human body (Underwood, 1977; CEC, 1978). Both the liver and the kidney acts as the organ for the accumulation of Cd and about 50% of any accumulated Cd is found in these organs (CEC, 1978).
The data in Table - 3, reveals that Cd exposure due to ingestion of Betwa River Water to a child is about 2.68 x 10”05 mg/kg-day, while for average life period, it is about 0.05868 mg/kg-day. The adults on the other hand exposed to Cd concentration, would be able to absorbed about 2.23 x 10”’ mg/kg-day Cd through Gl tract. However, if they are using the same water throughout their average life time and whole life time period, the receptor would be exposed to about 0.47212 mg/kg-day and 0.5698 mg/kg-day Cd respectively. However, in Kaliasot River Water the Cd contents are BDL therefore, absorption would not affect the receptor health.
Fergusson (1990) estimated that if a person is ingesting 1.5 liter of water with 10 μg/1 Cd concentration, the Cd intake would be around 15 u.g d”1 per day and Cd uptake would be 0.9 u,g d”1 per day with 0.06 absorption factor. However, the absorption of Cd from guts has been estimated to be 4.7 - 7% and the most common value used is 6% for an adult. The absorption increases to around 10%, if the person is suffering from calcium and protein deficiency. Considering the FAO/WHO maximum daily tolerable intake of 57-71 jig d”1 per day per person Cd (Fergusson, 1990), it appears that a large number of receptor population of the Mandideep area, although not within this limit at present but chronic exposure to life time for Betwa River Water may absorb sufficient Cd, leading to health hazard problem. However, Cd is normally associated with induction of hypertension, cirrhosis of the liver, pulmonary emphysema and lung cancer (Higgins and Bums, 1975). In case of oral intake nausea, vomiting, salivation, diarrhea and abdominal cramps are common symptoms of Cd poisoning (Klaassen, 1991)
Cr is an important ingredient of steel and other alloys. It is used in leather tanning, explosives, ceramics, paint pigments, photography and wood preservations. In Mandideep area wastes from idustries is the source of Cr pollution. However, fertilizer materials contain several thousand ppm of Cr as additional source of water pollution (Kannan, 1995). Cr exist in several valence state.
1 hexavalent Cr is many times toxic than trivalent form. The Cr exposure to human population is mainly through food and drink. The water ingestion data for Cr exposure to Betwa River Water and Kaliasot River Water to a child is about 8.69 x 10’05 mg/kg-day and 6.93 x 10”06 mg/kg-day, while for average life time period it is about 0.1902 mg/kg-day and 0.01512 rng/kg-day respectively. The adults on the other hand exposed to Cr concentration in both type of waters would be able to absorbed about 7.2 x i04i:> rng/kg-day and 5.74 x 10 ~°6 mg/kg-day Cr through GI tract. However, for average life timeand whole iife time period the receptor adult would be exposed to about 1.52424 mg/ kg-day and 1 .8396 mg/kg-day Cr for Betwa River Water while for Kaliasot River Water, the absorption would be 0.12064 mg/kg-day 0.1456 mg/kg-day. Thus, exposure to Cr concentration in Betwa River Water isgreater than Kaliasot River Water. However, studies on absorption factor of Cr, through GI tract is limited, but it is estimated that daily intake of Cr per person is in the range of 150 μg to 280 μg in different countries (Kannan, 19995). Exposure to Cr ^ causes dermatitis, allergic skin reactions and gastrointestinal ulcers. The Cr’6 is a teratogens as well as carcinogens, causing bronchogcnic cancer. the toxic Cr’6 is reduced to less toxic Cr° due to stomach acidity.
Fe has got less concern to health hazards but it is still considered as nuisance in excessive quantities. The water ingestion exposure to Fe concentration in Bctwa River Water and Kaliasot River Water for a child is about 4.11xl0~03 rng/kg-day and S^lxl0’03 mg/kg-day respectively. However, average life time exposure to a child would absorbed about 9 mg/kg-day Fe, from ingestion of Bctwa River Water while from Kaliasot River Water he would be exposed to 7.4674 mg/kg-day Fe eoneeniraliori. On the other hand an adult exposed to Belwa River Water, would be absorbed about 3.4xl0°3 mg/kg-day, which is estimated to 71.978 mg/kg-day and 86.87 mg/kg-day Fe for average life time and whole life time period respectively. In the same way Fe exposure to Kaliasot River Water ranges from 59.6994 mg/kg-day to 72.051 mg/kgday respectively for average life time and whole life time period. Thus, Fe exposure to Betwa River Water is more than Kaliasot River Waters. Fe is an essential component of several enzymes and structures including hemoglobin and the cytochromes. The recommended daily allowance of Fe is 10 mg for man and 18 mg for woman. Normally 5 - 15% of the ingested iron is absorbed. However, long term Fe exposure has resulted in siderosis (moiling of lungs) Kannan, (1995). Sullivan (1981 and 1989) has proposed that iron overload is a significant factor in isochemic heart diseases and that the high iron status of westerners is the cause of their excess rate of heart disease as compared with the people in underdeveloped countries.
Ni is used in alloys, metal plating and batteries. The main source of Ni in the environment is from burning of fossils fuel and mineral processing. Typical soil contain 10 - 100 mg/kg Ni (CEC, 1979), Ni is an important micronutrient for microorganisms, animals and humans but not to plants. The study of data from Mandideep area shows that Ni is present in substantial amount both in Betwa River Water and Kaliasot River Waters. The water ingestion exposure to Ni concentration in Bctwa River Water for a child aged 6-12 years is of the order of 2.48x10”04 mg/kg-day and for Kaliasot River Water the values are quite less i.e. 1.38xl004 mg/kg-day. For average life time exposure the values are 5.4312 mg/kg-day for Betwa River Water and 0.3024 mg/kg-day for Kaliasot River Waters. The adults on the other hand exposed to Ni concentration of Betwa River Water would be able to absorbed about 4.3616 mg/kg-day and 5.264 mg/kg-day Ni for average life time and whole life time period. However, for Kaliasot River Water the observed absorption for an adult would be about 2.41338 mg/kg-day and 2.9127 mg/kg-day for average life time and whole life time period. Absorption of Ni through GI tract seems to be very low i. e. <10%. However, Underwood (1977) reported higher values >10%. EPA (1979) suggests that evidence of accumulation of Ni by various tissues is less. However, certain diseases in man give rise to an elevated Ni level into tissues but the reason is not fully understood (Underwood, 1977).
Ni is relatively non-toxic element and therefore; the contamination of food by Ni does not pose serious health hazards. Sharma, (1995). The permissible dietary intake of Ni is about 300 - 600 μg/day Dara, (1993). However, high-level occupational exposure to Ni produces renal problems and other effects such as vertigo and dyspnoea (CEC, 1979). Human beings working in industrial sector are exposed to Ni carbonyl with initial symptoms like nausea, dizziness, headache and chest pain etc. Alter one to five days severe pulmonary symptoms like trachi-cardia and extreme weakness is developed and even death may occur within 4-13 days. Therefore, Ni dust is carcinogenic.
Pb in the environment exist entirely in the inorganic form but small amount of organic Pb results from the use of leaded gasoline (Trin, 1979). The use of Pb in various industries including pesticides is important source of Pb in the environment. Pb level in sewage sludge varies between 2000 - 8000 ppm and its use as fertilizer may add subsequent contamination to soil and waters. The overall human exposure to Pb is primarily from food and drinks. An exposure assessment study data to Bctwa River Water for a child is about 3.22x10”03 mg/kg-day , while for average life time period it is about 7.0518 mg/kg-day . The adults exposed to Pb concentration would be able to absorb about 5.34xl0”04 mg/kg-day Pb through GI tract. However, if they are using the same water throughout their average life time and whole life time period the receptor would exposed to about 11.3042 mg/kg-day and 13.643 mg/ kg-day Pb respectively. For Kaliasot River Water, the Pb concentration are diluted to possible level therefore, if child exposed to this water, he would uptake about 4.48x10”04 mg/kg-day Pb content with a value for average life time period would be 0.9810 mg/kg-day.Similarly, if an adult is exposed to similar concentration in Kaliasot River Waters, he would uptake about 7.43xl0”05 mg/kg-day Pb through Gl tract. While using this water for average lifetime and whole life time, an aduk would exposed to about 1.57296 mg/ kg-day and 1.8984 mg/kg-day Pb concentration respectively. The variation in the absorbed values for a child and an adult may be accounted due to different value of absorption factor. Fergusson (1990) estimated that if a person (adult) intake 1.5 Id”1 water with Pb concentration 20μg Id”1, the Pb intake would be 30 μ.g Id”1 and uptake would be 3 u.g Sd”! with 0.10 absorption factor. The FAOAVHO recommended tolerable daily intake of Pb from food and water is set at 430 μg Id”1 and Pb level 300 μg Id”1 is suggested for children (USPHS). This estimate level of intake based on the Pb level in faeces, assuming a 10% absorption factor. Considering the experimental intake values, the Pb concentration found in Betwa River Water is far above this limit. However, in Kaliasot River Water, the Pb level is relatively low. Therefore, Pb exposure to potential receptors of Betwa River Water is expected to be more than Kaliasot River Water. Although, it may be mentioned here that a high Ca and Fe diet decreases Pb absorption and when these elements are deficient, Pb absorption increases. (Fergusson, 1990).
Relationship between Pb intake and blood Pb level have been extensively studies and reviewed. Pb is understood today to cause adverse effects at the level of exposure that produces no clinically detectable symptoms. This recognition of sub-clinical toxicity first arose from studies in young children showing that chronic asymptomatic exposure to Pb could cause irreversible injury to the nervous system (Needleman, et al. 1979; Bellinger, et al. 1987; Dietrich, et al. 1991 ; McMichael, et al. 1988 and Wasserman, et al. 1992). Signs and symptoms of chronic Pb poisoning (plumbism) can be divided into six categories i.e. gastrointestinal, renal, neuromuscular, CNS, hematological and others. The neuromuscular and CNS syndrome usually results from intense exposure, while abdominal syndrome is a common manifestation of vary slowly and insidiously developing intoxication. Klaassen, (1991) suggest that CNS syndrome is common among children while gastrointestinal syndrome is more prevalent in adults. However, chronic exposure to Pb may cause weight loss, constipation and loss of teeth. If large amount of Pb is absorbed rapidly, a shock syndrome may be developed due to massive loss of gastrointestinal fluids. Other signs and symptoms of chronic Pb poisoning are an ashen colour of face and pollar of lips, retinal stippling appearance of premature aging with stood posture, poor muscle tone and emacian and a black and grayish so called Pb line along the gingival margin (Klaassen, 1991).
Sn is a silvery white metal, used in manufacture of alloys. However, several compounds of Sn are used extensively in medicine, which are important source of Sn in the aquatic environment. Sn is not an essential trace metal to humans but some studies suggest that 1 -2 mg Sn/kg diet seems to be essential for the normal growth of rats. Human exposure to Sn occurs from the use of canned food products and drinks.
The average concentration of Sn in Detwa River Water is eleven times greater than the Kaliasot River Water. The calculated value of water ingestion exposure to a child from Betvva River Water is about 6.05x10413 mg/kg-day, if child exposed to this concentration he would be able to absorb about 13.2492 mg/kg-day Sn during average life time period at the rate of 7% absorption factor. However, if an adult is exposed to this water, he would absorb about 5.02 x lO-0.3 mg/kg-day Sn concentration. If a person uses Betwa River Water with 2.508 ppm Sn concentration for average life time and whole life time period he would uptake about 106.2734 mg/kg-day Sn and 128.261 mg/ kg-day Sn concentration respectively. In the same way if a child aged 6-12 years exposure to Kaliasot River Water he would uptake about 5.53x10”04 mg/kg-day Sn, which would comes around i.2108 rng/kg-day for average life time exposure. On the other hand if an adult uses Kaliasot River Water with average concentration of 0.229 ppm Sn, he would exposed to about 4.58x10”04 mg/kg-day Sn. which would be accounted to about 9.6976 mg/ kg-day Sn for average life lime exposure and ! 1.704 mg/kg-day Sn for whole life time period. Kannan (1995) suggests that Sn intake through canned food varies from 50 - 500 mg Sn/kg food. However, the accepted maximum tolerance level of Sis is about 250 mg/kg. Consumption of Sn containing food especially the amount exceeds to 1400 } >pm induces varied symptoms like nausea, abdominal cramps, vomiting, headache, diahorrea and iever. People consuming contaminated food and drinks daily over a long period may suffer from disturbance of gastric acid secretion, iron absorption and hem metabolism. Kannan (1995) indicates that most of the absorbed Sn is deposited in the bones followed by mussels and liver.
Risk characterization is the process of estimating the probable incidence of adverse impacts to potential receptors under various exposed conditions. It is the final step in risk assessment process and the first input to the risk management process. Its purpose is to present the risk manager with synopsis and synthesis of all the data that should contribute to a conclusion with regards to the nature and extent of risk. Therefore, risk characterization involves the integration of the exposure and toxicity assessments to arrive to an estimate of risk to the exposed population both qualitatively and quantitatively. Looking to the significance of risk characterization in hazardous waste management, an attempt has been made to estimate the carcinogenic risks (CR) due to ingestion exposure of available concentrations of Cd, Cr, Fe, Ni, Pb, and Sn in Betwa and Kaliasot River Waters of Mandideep area. The carcinogenic effects of the above trace metals of concerns are calculated according to the equation given by US EPA (1989i). The risk of contracting cancer can be estimated by combining information about the carcinogenic potency of a chemical and exposure to the substances. However, for potential carcinogens, risk is estimated as the incremental probability of an individual contracting cancer over a life time as a result of exposure to the potential carcinogens. The equation used for the calculation of CR represent the linear low-dose cancer risk model and is valid only at low risk levels. The values are estimated by mutiplying the career SF, which is the upper 95% confidence limit of the probability of a carcinogenic response per unit intake over a life time exposure, by the estimated intakes - yielding incremental risk values. (Asante - Duah, 1993). However, it may be pointed out that calculated CR values are generally dimensionless probability of an individual developing cancer (US EPA, 1989i). The calculated values of CR are given in Table no. 4 for above trace metals. The estimated values for Cd, Cr, Fe, Ni, Pb, and Sn in Betwa River Water is of the order of 43.8307 ; 21.9004 ; 109.3693 ; 73.1116 ; 72.9628 and 51.1761 respectively. However, for Kaliasot River Water, the values for estimated carcinogenic risk is about 21.7314 ; 109.3014 ; 72.8175 ; 73.0144 and 51.1114 for ingestion exposure to Cr, Fe, Ni, Pb and Sn respectively. This probability of carcinogenic risk (CR) may increase with increasing concentration of above mentioned elements in surface water in due course of time.
Table 4: Estimation of carcinogenic risk (CR) to water ingestion exposure of Betwa and Kalaisot river waters in Mandideep industrial area.
The above discussions point out that Cd, Fe, Ni, and Pb, concentrations in Betwa River Water and Kaliasot River Waters of Mandideep industrial area, is at the alarming stage particularly at the point where effluent water joins the river waters. The water ingestion exposure through oral route is however, calculated after considerable dilution, points out that a significant quantity of Cd, Fe, TMi and Pb contents will be absorbed by a children 6-12 years and an adult exposed to average life time and average whole life time period respectively. Chronic exposure to these trace metals may initiate variety of health hazard problems including development of cancer related diseases as discussed in relation to individual element above.
Copyright © 2024 Research and Reviews, All Rights Reserved