Eco-chemical Characterizations of. Mining Areas of Western Part of

Transcription

1 Eco-chemical Characterizations of Surface Water Bodies in and around Mining Areas of Western Part of Kachchh, Gujarat By Sonali Pati and B. Anjan Kumar Prusty Gujarat Institute of Desert Ecology, PO Box# 83, Mundra Road, Opp.Changleswar Temple, Bhuj , Gujarat

2 Introduction Increased Industrialization and overexploitation has lead to the deterioration in the quality of water resources. Opencast mining Destroys existing vegetation Destroys the genetic soil profile, Displaces or destroys wildlife and habitat, Degrades air quality, Alters current land uses, Permanently changes the general topography of the area mined Damage surface and ground water during all phases of exploration and use. Source 1. waste disposal, 2. Storage, 3. Transportation and 4. Handling of commercial materials, 5. Mining operations

3 Mine water may be dominated by 1. Low ph 2. Elevated sulphate concentrations 3. Elevated concentrations of metals. How it will affect Surface Water? Dissolution and transport of metals and heavy metals by run off. Aerial fallout from atmospheric pollutants. Leaching In Western Part Of Kachchh, Miningoperations are open cast The resultant overburden is dumped in nearby places. The surface water bodies which are closed to mining sites seem to receive contaminants due to mining i processes through hsurface run off or aerial fallout from atmospheric pollutants.

4 Objectives 1. Characterize the surface water in and around the mine sites 2. Evaluate its suitability for domestic usage 3. Evaluate the spatial scale difference in the level lof contamination i

5 Study Area Materials and Methods 1. 2 nd largest district in the country 2. Area: 45,652 km2 3. Two Ranns Saline deserts of Great Rann of Kachchh hh (17,500 km2) Little Rann of Kachchh (5,180 km2) 3. Present study was confined in three select talukas i.e. Abdasa, Nakhatrana and Lakhpat with an area of about 5000 km The entire area is rich in Lignite, Bauxite, Limestone and Bentonite.

6 Climate is semiarid with a temperature variation of about 4 to 46 C. Experiences e three distinct seasons, s, i.e. winter, summer and monsoon. Average rainfall is 334 mm/ annum Three active mines are present Two thermal power plants are located at Akrimota and Panandhro

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8 Field Sampling 40 grids were selected (5x5) within 10 km radius of three mine sites. The grid having more than one village, the village which h comprised of more than 66% (2/3rd) of the area, was taken into consideration. 48 water samples were collected from 16 surface water bodies which include ponds, lakes and dams. Study carried out during pre-monsoon (April- June) season.

9 Sample processing The Samples Collected in pre-cleaned polyethylene bottles. Prior to sampling, the bottles were thoroughly rinsed two to three times using water to be sampled. The collected samples were placed immediately in an ice-box and transferred to the laboratory for further analysis.

10 Sample analysis Basic Parameters: ph, EC, TA, TDS, TH, Cl 2, DO, BOD Cations: HCO 3-,CO --,SO --,NO Alkali metals: Na, Ca, Mg, K & Li Heavy Metals: Fe, Mn, Pb, Cu, Zn, Co, Ni and Cd. To know the suitability for irrigation: SAR, pna, rca, rhco3 and RSC were also estimated empirically.

11 Data Analyses To find the range, distribution and association of different parameters Basic descriptive statistics and Two Tail test of Correlation were performed on the analytical data using MEGASTAT Univariate tests were performed to assess the variation of distribution of all the physico-chemical parameters with respect to their location from the mining site following the General Linear Model (GLM) coupled with One Way Analysis of Variance (ANOVA) test at the α = level. These statistical tests were performed using SPSS11.0

12 Results ph ph SLM B JWB SLM A MP EC GD GVP PVP PM L GP VN ph Value micros/cc m Series1 M P SLM A SLM B JWB M V P V N G P GVP PVP PML G D

13 TA, CO3 & HCO3 TA CO3 HCO3 JWB SLM B SLM A MP VN TH and Ca ( CaCO3) GP PML PVP GVP GD Series1 Series2 JWB SLM B MP SLM A VN GP PML PVP GVP GD mg/l mg/l

14 TDS & Chloride Series1 Series2 DO BOD VN GP JWB MP SLM A SLM B DO & BOD VN ML GP JWB MP SLM MA SLM MB PML PM ML PVP PVP GVP GVP GD GD mg/l mg/l

15 Sulphate mg/l Sulphate 1.0 GD GVP PVP PML GP VN MP SLM A SLM B JWB Nitrate mg/l Nitrate GD GVP PVP PML GP VN MP SLM A SLM B JWB

16 Na & Ca Na Ca Mg Mg P VP P M L M P SLM A S LM B JWB VN GP GV P GD m g /l m g /l SLM B JWB SLM A MP VN GP PML PVP GVP GD Pottasium K 2.0 Li Li N S M P SLM A SLM B J W B D P V N G P GVP P VP P M L g /l g/l m m G D SLM A SLM B J W B M P V N G P P M L G V P P VP G D

17 Copper Zinc Series Zn M P SLM A SLM B JWB M V P m icrogram /l Microg ram /l M M L M V P M P S LM A S LM B J WB V N P M L G P G V P P VP G W B G D GD GW B GV P P VP PML G P VN M M L Lead Iron P m /l Microgram/l Pb 1 Fe M P S LM A SLM B JWB M V P M P SLM A SLM B J W B V N G P PVP PML GVP G D GD GVP P VP PML GP V N M ic ro g ra

18 Nickel Ni Cadmium Cd G V P PVP M P S LM A S LM B JWB VN GP PML PVP GV P GD G M ic r o g r a m /l 10 Microg ram /l25.0 S LM A S LM B J W B M P V N PML G P G D S Manganese Cobalt Microgr a m/l Co M P SLM A SLM B JWB VN GP PML PVP GV P GD Mn SLM A SLM B J W B M P V N G P PML G D G V P PVP M ic r o g r a am /l

19 All the water bodies varied significantly in the case of all the parameters analyzed in the present case(glm, ANOVA, P < 5). Among the heavy metals studied, most of them are positively correlated among each other. Most of the heavy metals were found to be negatively correlated with anions such as CO 3 and HCO 3, and total hardness of water. Mn was positively correlated with CO 3.

20 Discussion In all the wetlands, the ph of water exceeded >7.0 which might due to; 1. Being rain fed, most of the wetlands receive runoff from their respective watershed, and as observed during present study the soil in the area are highly alkaline with ph ranging between 8.6 and Although mine pit lakes are highly acidic, ph of 3.6, as observed during the reconnaissance survey, implementation of specific treatments methods by mining authorities, such as addition of calcite to neutralize the ph of water in such lakes had increased the ph up to near neutral level

21 The BOD level is high observed in VNP wetland and is suggestive of high h contamination ti due to organic wastes of animal origin as it is used for livestock purposes The TDS level in GD, GWP, GVP, GP, VNP, and water bodies were < 1000mg/l and indicative of fresh water type. Higher levels of TDS might be due to the gradual release of ions and salts from the bottom sediment during the post monsoon season. Cl 2 content was also high which was not found suitable for domestic use.

22 The hardness was up to a level of 6400 mg/l in mine lake and gradually decreased in distance off mining. This could be associated with pumping out of ground water during mining of lignite at both the mine sites. The coal mine water is characterized by the dominance of SO 4. But the level in the present case was very low and might be associated with less pyrite formation and also be due to possible bacterial action. Na, Ca and Mg were high in most of the water bodies and exceeded the permissible limit of stipulated standards.

23 GD and wetlands were used for irrigation purposes. In these 2 wetlands 1. SAR values as 1.84 meq/l and 1.82 meq/l respectively and are suggestive of low sodium hazard of water from irrigation point of view. 2. On the basis of TDS, both the water body was within permissible limit of irrigation water quality standards ( mg/l) 3. The RSC values in GD and water bodies were and meq/l (<1.24) respectively and are safe for agricultural usage.

24 Of all the heavy metals Cu was found least concentrate and this might be due to 1. The dominating presence of Ca, Mg and HCO 3 ions. 2. As there is possible input of organic and animal waste in many of the water bodies and the resulting higher formation of colloidal forms of Fe and Mn may be an important reason for the reported concentrations.

25 Water bodies constitute a multimetal- multiligand system owing to the natural pathways of metals in such systems. Cu being capable of forming strong complexes with organics would associate itself with organic films covering the Fe and Mn colloids becoming itself unavailable to the water column and organic extractants as used in this exercise, i.e. APDC-MIBK. Fe con. Is found low due to less % of pyrites in lignite.

26 Ni, Cd and Co were found in higher concentrations; with the concentration of Cd exceeding the permissible limit for both domestic and agricultural usage. Cd was found in the level of µg/l in GD wetland,this metal is likely to pose the problem of bioaccumulation i.e. being carried over through h different tropic levels l in the ecosystem and cause potential health risks to humans and animals. Ni in was recorded to be 110.9µg/l and owing to the usage of this water body for domestic purposes, might also affect human health. According to Taylor et al animal faeces contribute Ni into the wetlands.

27 The higher level of Co might be due to the input of allochthonous substances into these aquatic systems. GP wetland was reported to have the highest concentration of Pb among all the water bodies. Owing to its proximity to a major highway, this could be due the vehicular exhausts. Pb might also be associated with SPM arising from various sources including automobiles in the atmosphere.

28 Conclusion All the mine lakes were rich in Ca, Mg and hardness with lignite mines having the maximum level for the cations. The water bodies adjacent to the major roads were concentrating Pb. Both the dams, i.e. Godhathad and Lifri, mostly constructed for irrigation purposes, were reported to have higher values of Cd The limestone mines contained higher levels of Ni and Co

29 Study revealed that 1. some heavy metals exceeded the maximum permissible limits for irrigation purposes, hence remedial measures should be undertaken owing to serious health implications. 2. Since many of the water bodies have reported lower levels of hardness and bicarbonates, further examination of possible complexation of heavy metals with these anions and cations would contribute in containing the problem of heavy metals contamination due to mining activities. 3. Study of seasonal gradient in the availability of these contaminants in the water bodies would also add on to existing knowledge base on the behavior of the heavy metals in these systems, although the same is poorly understood.

30 Thank You