Scholarly article on topic 'Characterization of Leachate and Its Impact on Surface and Groundwater Quality of a Closed Dumpsite – A Case Study at Dhapa, Kolkata, India'

Characterization of Leachate and Its Impact on Surface and Groundwater Quality of a Closed Dumpsite – A Case Study at Dhapa, Kolkata, India Academic research paper on "Earth and related environmental sciences"

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Abstract of research paper on Earth and related environmental sciences, author of scientific article — S.K. Maiti, S. De, T. Hazra, A. Debsarkar, A. Dutta

Abstract The possible enduring environmental impact of a closed landfill on groundwater and surface water quality depends on the leachate characteristics. Post closure management of closed landfill site is needed for averting the environmental hazards. The present investigation was aimed to characterize leachate and its impact on surrounding water resources of closed dumping site at Dhapa (Kolkata, West Bengal, India). Three sampling points were identified for collection of samples fromand near the closed dumping site. All the samples were examined for pH, TDS, Cl-, BOD5, COD, NH4 +-N, Zn, Cu, Cr, Cd, Hg and Pbto study the seasonal variation of significant parameters. The laboratory analysis shows prevalence of high value of TDS (8994.16±6239.2mg/L), COD (4191.66±2282.19mg/L), NH4 +-N (1165.93±658.4mg/L), Cl− (4356.65±1304.84mg/L) and two heavy metals viz. Pb (0.56±0.33mg/L) and Hg (0.42±0.44mg/L) in the leachate samples, which have exceeded their respective standards specified in “Municipal Solid Wastes (Management and Handling) Rules, 2000” for disposal of treated leachates. The maximum concentration of afore-said heavy metals viz. lead and mercury are found to be 0.15±0.18mg/L and 0.16±0.28mg/Land 0.23±0.21mg/L and 0.1±0.05mg/L respectively for surface and ground water resources, which have exceeded their respective permissible limits recommended by Bureau of Indian Standards (BIS). The extent of contamination of local water resources necessitates appropriate treatment of leachate before getting discharged and establishes the significance of post closure management of the closed dumpsite.

Academic research paper on topic "Characterization of Leachate and Its Impact on Surface and Groundwater Quality of a Closed Dumpsite – A Case Study at Dhapa, Kolkata, India"

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Procedía Environmental Sciences 35 (2016) 391 - 399

International Conference on Solid Waste Management, 5IconSWM 2015

Characterization of Leachate and Its Impact on Surface and Groundwater Quality of a Closed Dumpsite - A Case Study at

Dhapa, Kolkata, India

S.K. Maitia\ S. Dea, T. Hazrab, A.Debsarkarb, A. Duttab

a Research Scholar, Jadavpur University, Kolkata, India b Assistant Professor, Jadavpur University, Kolkata, India

Abstract

The possible enduring environmental impact of a closed landfill on groundwater and surface water quality depends on the leachate characteristics. Post closure management of closed landfill site is needed for averting the environmental hazards. The present investigation was aimed to characterize leachate and its impact on surrounding water resources of closed dumping site at Dhapa (Kolkata, West Bengal, India).Three sampling points were identified for collection of samples fromand near the closed dumping site. All the samples were examined for pH, TDS, Cl", BOD5, COD, NH4+-N, Zn, Cu, Cr, Cd, Hg and Pbto study the seasonal variation of significant parameters. The laboratory analysis shows prevalence of high value of TDS (8994.16±6239.2mg/L), COD (4191.66±2282.19mg/L), NH4+-N (1165.93±658.4mg/L), Cl" (4356.65±1304.84mg/L) and two heavy metals viz. Pb (0.56±0.33mg/L) and Hg (0.42±0.44mg/L) in the leachate samples, which have exceeded their respective standards specified in "Municipal Solid Wastes (Management and Handling) Rules, 2000" for disposal of treated leachates. The maximum concentration of afore-said heavy metals viz. lead and mercury are found to be 0.15±0.18 mg/L and 0.16±0.28mg/Land 0.23±0.21 mg/L and 0.1±0.05 mg/L respectively for surface and ground water resources, which have exceeded their respective permissible limits recommended by Bureau of Indian Standards (BIS). The extent of contamination of local water resources necessitates appropriate treatment of leachate before getting discharged and establishes the significance of post closure management of the closed dumpsite.

© 2016 The Authors.Publishedby Elsevier B.V. Thisis an open access article under the CC BY-NC-ND license (http://creativecommons.Org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of the organizing committee of 5IconSWM 2015

Keywords:Dumping site, Leachate, Groundwater, Surface water, Seasonal variation;

* Corresponding author.

E-mail address:maitisanjib28@gmail.com

1878-0296 © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license

(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of the organizing committee of 5IconSWM 2015

doi:10.1016/j.proenv.2016.07.019

l.OIntroduction

Indecorous handling of solid waste has resulted in serious ecological, environmental and health complications (Salami et al., 2014).The interment of municipal solid waste in landfills is one of the most common disposal methodologies adopted in most of the countries. Landfill leachate is generated when excess rainwater percolates through the waste layers in a landfill. Landfill leachate may be categorized asa water-based solution of four groups of contaminants (dissolved organic matter, inorganic macro-components, heavy metals, and xenobiotic organic compounds. The most important potential environmental influences associated with landfill leachate are contamination of groundwater and surface water (Kjeldsen et al., 2002). Groundwater is a worldwide significant and valuable renewable resource for human life and economic growth. Groundwater pollution is principally due to the process of industrial development and urbanization that has gradually developed over time without any esteem for environmental significances. Only just, the impact of leachate on groundwater and other water resources has attracted a lot of care because of its devastating environmental significance. Leachate migration from landfills poses a high risk to groundwater resource if not satisfactorily managed (Patil et al., 2013).

Most of the lakes and rivers in the world are heavily polluted nowadays. There are limited lands accessible for crude solid waste dumping. The growing generation and buildup of wastes produce serious environmental, economic, and social difficulties in both developed and developing countries (Dharmarathne et al., 2013). Electronic goods, painting waste, used batteries, etc., when dumped with municipal solid wastes increase the heavy metals in dumpsites and dumping devoid of proper segregation of hazardous waste can further elevate toxic environmental effects. Environmental impact of land filling of MSW can usually result from the run-off of the noxious compounds into surface water and groundwater which ultimately lead to water pollution as a result of percolation of leachate (Ramaiah et al., 2014). The groundwater zones and surface water bodies (ponds) around the Dhapa closed dumping ground are usually affected by landfill leachate. Consequently, diseases such as hepatitis, diarrhea, vomiting, abdominal pain, dysentery etc. have been frequently occurring in majority of the people residing adjacent to Dhapa area. In the present study, considering the gravity of the situation, the effects of leachate percolation and dispersion have been studied on the surrounding groundwater and surface water courses of Dhapa closed landfill site of Kolkata.

2.0 Study Area

The Dhapa disposal site of Kolkata is located in the eastern part of India at 22.82°N and 88.20°E and 26 km from the Dumdum Airport. Kolkata is the capital of the state of West Bengal located in the eastern part of India. The climate in Kolkata is tropical and rainy.

Fig. 1. View of the Study Area (Source: Google earth)

Fig. 2. Location of Dhapa Dumping site at Kolkata

The 24-hour average temperature is 26.6° C. Average annual precipitation in Kolkata is 1,625 mm, of which over 95 percent falls in the monsoon months of June through September. It is one of the most highly populated cities in the country.The city generates about 3,000 tons of municipal solid waste (MSW) daily at a rate of 450-500 g per capita per day (Chattopadhyay et al., 2009).There are three disposal sites in the KMC area at Dhapa, Garden Reach and Noapara of which Dhapa is the most important one (Hazra et al., 2009).The present dumping area of Dhapa is about 35 hectares. It consists of two unlined dumpsites, one closed dump of area is about 12ha and one active dump of area is about 23 ha. The Dhapa Disposal Site is owned by Kolkata Municipal Corporation (KMC).The location of Dhapa dumping site is presented in Figure-1.

3.0 Materials and Methods

3.1 Sample Collection

To understand the effect of leachate generated from closed landfill site on groundwater and surface water, one leachate sample, one groundwater (Tube well) and one surface water (Pond) sample were collected from the dumping ground and the surrounding areas during pre-monsoon, monsoon and post-monsoon of the year 2013 and 2014. Site specifications for sampling points are presented in Table 1 and Figure 2.

Table 1: Site Specification for Sampling

Sampling locations

Latitude and Longitude

Notation

1 Leachate Collecting Point (LCP)

2 Tube well

3 Pond

22°32'43.8"N 88°25'12.4"E 22°32'43.4"N 88°25'13.0"E 22°32'39.3"N 88°25'17.5"E

Leachate Groundwater Surface water

L G.W S.W

Table 2:Details of Parameters Monitored, Methods of Analysis and Instrument used

Parameter Method Adopted Apparatus/Instrument Used

pH Electrometric Method Electronic pH meter

Electrical Conductivity (EC) Laboratory Method Deluxe conductivity meter

Total Dissolved Solid (TDS) Gravimetric Method

Total Hardness(TH) EDTA Titrimetric Method

Chemical Oxygen Demand(COD) Open Reflux Method Digestion vessels

Biochemical Oxygen Demand (BOD5) Winkler's Method Air incubator

Chloride (Cl-) Argentometric method

Sulphate (SO42-) Phosphate (PO43-) Ammoniacal nitrogen (NH4+-N) Arsenic (As), Cadmium (Cd), Chromium (Cr),Mercury (Hg), Lead (Pb), Zinc (Zn), Copper (Cu) Turbidimetric Method Colorimetric Method Ammonia-Selective Electrode Method Graphite Furnace Atomic Absorption Spectrometric Method UV-Visible Spectrophotometer (Varian Make, Model-50 Bio) UV-Visible Spectrophotometer (Varian Make, Model-50 Bio) Expandable Ion analyzer, EA940 (Orion Research) Atomic Absorption Spectrophotometer (AAnalyst 400, Perkin Elmer)

3.2 Material Preservation:

All the samples were collected in pre-cleaned polyethylene containers of 5.0L capacity and after returning to the laboratory the samples were stored in 4oC in the incubator and were eventually analyzed as per the Standard Methods (APHA, 17thEdition).Samples for heavy metals were preserved separately by adding 1.0 ml conc. nitric

acid so that there will be no precipitation of the heavy metals. 3.3: Sample Analysis:

The water quality parameters monitored under the purview of the present study and the methods of determination followed are furnished in Table 3.2. The results of the physico-chemical parameter and level of trace metal concentration of leachate, groundwater and surface water samples are compared with the limits prescribed by Municipal Solid Wastes (Management and Handling) Rules, 2000, Bureau of Indian Standard (BIS) 2012 and Water Quality Standards in India (Source IS 2296:1992)on the basis of their designated best uses respectively.

3.4: Statistical Analysis:

In order to explore multiple inter-relationships among all the physico-chemical variables and trace metals, Pearson's correlation was carried out by using Statistical Package for Social Sciences (SPSS 20.0). Correlation analysis is a preliminary descriptive method for estimation of the degree of association among the variables involved. The function of the correlation analysis is to measure the intensity of association between two variables.

4.0 Results and Discussion

4.1. Leachate characterization:

The physico-chemical characteristics of leachate sample were analyzed for all the three seasons in the year 2013 and 2014. The results of physico-chemical characterization are presented in Table-4.1. The pH value of the collected leachate was significantly alkaline. Fatta et al., 1999 also obtained alkaline range pH values in leachate. The value of pH represents the biological stabilization of the organic components.

The concentrations of EC and TDS of the collected leachate were high. Fatta et al., 1999 and M or et al., 2006 also obtained high level concentration of EC and TDS. The high concentration of EC and TDS can be attributed to the presence of inorganic components, mainly high levels of various anions and the soluble salts. Total Hardness (TH) in the leachate samples might have been caused by the multivalent cations particularly calcium and magnesium. High concentrations of chloride were found in the leachate sample. The high chloride value justifies high range of TDS and COD value in the present study (Motling et al., 2013). For leachate sample, sulphate concentration was high and it might be due to the presence of different inorganic waste materials. Phosphates might have a variety of sources including agricultural fertilizers, domestic wastes, detergents, industrial process wastes etc. High range of ammoniacal nitrogen was obtained in leachate sample. A part of nitrogen might have been released with leachate as ammoniacal compound by aerobic and anaerobic decomposition of solid waste (Motling et al., 2013). The concentration of Biochemical oxygen demand (BOD5) in the collected leachate was also observed to be high, which was corroborated by Kjeldsen et al., 2002. According to this study, leachate was highly contaminated with organic matters.

High concentration of COD was found in the leachate samples. Kjeldsen et al., 2002 also obtained high values of COD in leachate samples. The present study indicates the presence of some recalcitrant organic constituents in the leachate. Among the heavy metals analyzed, except Hg and Pb, all other heavy metals were within the permissible limit as stipulated in Municipal Solid Wastes (Management and Handling) Rules, 2000. Mercury can be found in a variety of products, such as fluorescent and other lights, batteries, electrical switches and relays, barometers, and thermometers, much of which ends up in municipal landfills. The mercury contained in these products is mixed with leachate and that leachate may leach into the groundwater and surface water from the landfills. High concentration of Pb suggests that the wastes are mainly of municipal origin containing refused batteries, paint products, metallic items etc. (Kale et al., 2010).

4.2 Groundwater Characterization

The groundwater samples were characterized to ascertain the extent of pollution caused by leachate. The values were also compared with the Bureau of Indian Standard (BIS), 2012 to determine its compatibility as drinking water. The results are furnished in the Table 3.

In the case of groundwater samples, pH was within the acceptable range of drinking water standards. The value of EC was high in collected groundwater samples. Rathod et al., 2013 also obtained high value in groundwater sample. The high values of EC of groundwater sample indicate higher concentration of anions and cations. The TDS values of the groundwater samples were far above the permissible limit. High TDS value leads to objectionable taste, odor and color in water. The TH values were obtained above the permissible limit. The total hardness concentration of groundwater was high and may be due to faintly alkaline state. Cl- concentrations were above the permissible limit. Mor et al., 2006 also obtained high Cl- concentrations in groundwater sample.The pollution sources for Cl-might be due to the domestic effluents, fertilizers, and leachates. SO42 concentrations were well below the permissible limit. Zub et al., 2008 also obtained lower sulfate concentration in groundwater sample. Sulphate-reducing bacteria (SRB) may be present in soil or groundwater or surface water and it competes with methane-producing micro-organisms for the obtainable organic carbon, resulting in the formation of hydrogen sulphide. This phenomenon can be attributed to the microbiological reduction of sulphates into sulphides. Among the heavy metals, Hg and Pb were found above their respective permissible limits in the groundwater samples.

4.3 Surface Water Characterization

The physico-chemical characteristics of surface water sample are listed in Table 4.3. pH of the surface water samples was in the range recommended for the designated best use (E grade) by Water Quality Standards in India (Source IS 2296:1992). The total dissolved solid concentration in surface water was higher may be due to the leaching of various pollutants into water. Concentration of SO42- was also higher in surface water sample.

The excess chloride ion could be attributed to surface water contamination. The higher BOD5 and COD values indicate the presence of organic matter in water. The concentration of lead and mercury were obtained comparatively much higher in two surface water samples which also indicate to surface water contamination.

Table-3:Physico-chemical characteristics and level of trace metal concentrations in groundwater samples (G.W.)

Parameter* Pre-Monsoon (2013) Monsoon (2013) Post-monsoon (2013) Pre-Monsoon (2014) Monsoon (2014) Post-monsoon (2014) Mean ± SD Acceptable Limit (mg/L) (IS 10500)

pH 7.4 7.3 7.4 7.2 7.3 7.4 7.33±0.08 6.5-8.5

EC 1457 2114 2285 1991 1608 1764 1869.83±315.23

TDS 1020 1480 1600 1194 546 920 1126.66±385.92 500

TH 420 580 455 688 556 556 542.5±95.50 200

Cl" 445.86 415.83 372.17 445.18 409.87 799.04 481.32±157.99 250

SO42- 33.44 27.36 49.38 20.38 11.71 31.94 29.03±12.80 200

PO43- 0.23 1.5 0.03 0.12 0.13 0.13 0.35±0.56

NH4+-N 0.37 0.105 0.545 0.29 0.07 0.018 0.23±0.20 0.5

BOD5 0.28 0.75 0.4 0.23 0.9 0.32 0.48±0.27

COD 17 42 30 12 48 20 28.16±14.42

As 0.015 BDL 0.001 0.011 BDL BDL 0.009±0.007 0.01

Copper 0.002 0.015 0.002 0.004 0.029 0.004 0.009±0.01 0.05

Zinc 2.97 0.26 0.98 3.25 2.60 0.20 1.71±1.39 5

Chromium 0.023 0.075 0.033 0.052 0.09 0.031 0.05±0.02 0.05

Cadmium 0.015 0.001 0.012 0.012 0.004 0.017 0.01±0.006 0.003

Mercury 0.15 0.05 0.02 0.14 0.114 0.15 0.1 ±0.05 0.001

Lead 0.03 0.36 0.17 0.01 0.58 0.23 0.23 ±0.21 0.01

*All units are in mg/L except pH and EC (^mho/cm) BDL= Below Detection Limit

4.4 Result of Statistical Analysis

Some of the parameters were found to have statistically significant correlation with each other. According to Table 5 in leachate sample (L) TDS was well correlated with pH and EC. BOD5 is significantly correlated with COD and TH. Mercury (Hg) was also well correlated with EC and TH. According to Table 6 in groundwater sample (G.W) TDS was well correlated with EC. BOD5 and COD were significantly correlated with Pb. According to Table 4.6, in surface water sample (S.W), Cl- was well correlated with EC and TDS. NH^-N was significantly correlated with TDS

Table 4: Physico-chemical characteristics and level of trace metals in Surface water sample (S.W)

Parameter* Pre-Monsoon (2013) Monsoon (2013) Post-monsoon (2013) Pre-Monsoon (2014) Monsoon (2014) Post-monsoon (2014) Mean ± SD

pH 8.3 7.8 7.3 7.4 7.6 7.5 7.65±0.36

EC 2028 1728 4171 2640 1342 1715 2270.66± 1026.86

TDS 1420 1210 2920 1584 805 720 1443.16±798.24

TH 510 640 440 576 400 668 539±107.86

Cl" 220.67 158.99 295.94 298.42 127.98 141.8 207.3±76.49

SO42" 141.5 251.8 488.29 161.50 168.58 257.66 244.88±128.77

PO43" 0.881 3.29 1.28 0.41 0.58 0.35 1.13±1.11

NH4+-N 0.375 0.153 5.35 0.09 0.1 0.011 1.01±2.12

BOD5 13.56 38.02 36 12.16 9.7 3.7 18.85±14.47

COD 84 86.8 154.90 76 24 44 78.28±44.95

As 0.002 0.001 0.011 0.002 BDL 0.015 0.0062±0.0063

Copper 0.022 0.015 0.002 0.012 0.029 0.003 0.013±0.01

Zinc 0.37 0.167 0.205 0.29 0.134 0.2 0.22±0.08

Chromium 0.055 0.153 0.09 BDL 0.08 0.052 0.08±0.04

Cadmium 0.021 0.005 0.035 0.012 0.003 0.020 0.016±0.01

Mercury 0.03 0.04 0.025 0.75 0.03 0.12 0.16±0.28

Lead 0.06 0.43 0.03 0.041 0.34 0.03 0.15±0.18

*All units are in mg/L except pH and EC (^mho/cm) BDL= Below Detection Limit

Table 5: Pearson's correlation analysis of leachate samples (L)

pH EC TDS TH Cl" SO42" PO43" NH4+-N BOD5 COD As Cu Zn Cr Cd Hg Pb

EC .785 1

TDS .868* *4 .8 1

TH .783 .798 .682 1

pH EC TDS TH Cl- SO42- PO43- NH4+-N BOD5 COD As Cu Zn Cr Cd Hg

Cl" -.549 -.672 -.664 -.878* 1

SO42" .379 .585 .653 .670 -.934** 1

PO43" -.593 -.438 -.199 -.768 .436 -.098 1

NH4+-N -.520 -.495 -.853* -.274 .464 -.630 -.317 1

BOD5 .651 .722 .694 .945** -.986** .866* -.563 -.418 1

COD .656 .716 .691 .947** -.984** .861* -.574 -.412 1.00** 1

As .841* .806 .990** .738 -.755 .737 -.228 -.841* .776 .773 1

Cu .226 .221 .603 .298 -.629 .773 .291 -.799 .547 .540 .673 1

Zn -.331 -.315 -.219 -.789 .816* -.632 .701 -.068 -.832* -.838* -.329 -.265 1

Cr -.386 -.245 -.701 -.095 .255 -.393 -.399 .893* -.225 -.218 -.692 -.810 -.212 1

Cd .489 .683 .400 .918** -.851* .653 -.745 -.007 .891* .890* .483 .168 -.864* .187 1

Hg .658 .917* .600 .840* -.654 .478 -.615 -.188 .726 .720 .620 .077 -.450 -.028 .827* 1

Pb -.319 .187 -.397 -.025 .147 -.203 -.143 .566 -.136 -.145 -.400 -.593 .064 .654 .272 .402

Table 6: Pearson's correlation analysis of groundwater samples (G.W)

pH EC TDS TH Cl- SO42- PO43- NH4+-N BOD5 COD As Cu Zn Cr Cd Hg Pb

EC -.175 1

TDS .059 .837* 1

TH -.877* .240 -.086 1

Cl- .324 -.265 -.320 .126 1

SO42- .695 .466 .706 -.628 .020 1

PO43- -.193 .282 .391 .172 -.184 -.105 1

NH4+-N .212 .354 .586 -.469 -.553 .679 -.336 1

BOD5 -.168 -.018 -.278 .066 -.337 -.481 .462 -.478 1

COD -.023 .108 -.143 -.068 -.363 -.284 .438 -.348 .976** 1

As -.146 -.420 -.030 -.101 -.196 -.020 -.255 .437 -.627 -.709 1

Cu -.333 -.227 -.545 .227 -.260 -.725 .257 -.579 .938** .856* -.485 1

Zn -.444 -.485 -.407 .107 -.427 -.449 -.460 .280 -.184 -.303 .752 .070 1

Cr -.605 .047 -.299 .492 -.367 -.740 .427 -.530 .883* .791 -.464 .925** .051 1

Cd .453 -.237 -.049 -.272 .557 .458 -.691 .318 -.885* -.847* .446 -.788 .115 -.902* 1

Hg -.123 -.797 -.711 .213 .536 -.494 -.390 -.394 -.378 -.540 .534 -.089 .496 -.209 .501 1

Pb -.046 -.085 -.432 .071 -.070 -.470 .274 -.602 .946** .929** -.759 .921** -.283 .804 -.712 -.260 1

* Correlation is significant at the 0.05 level (2- tailed) ** Correlation is significant at the 0.01 level (2- tailed)

Table 7: Pearson's correlation analysis of surface water sample (S.W)

pH EC TDS TH Cl- SO42- PO43 NH4+-N BOD5

EC -.466 1

TDS -.320 .972** 1

TH .048 -.298 -.391 1

Cl- -.279 .853* .828* -.196 1

SO42- -.552 .782 .755 -.162 .355 1

PO43- .216 -.026 .121 .266 -.154 .236 1

NH4+-N -.425 .909* .918** -.465 .579 .912* .076 1

BOD5 -.083 .510 .638 -.069 .295 .635 .832* .591 1

COD -.165 .902* .948** -.159 .745 .760 .347 .852* .762

COD As Cu Zn Cr Cd Hg Pb

As -.456 .383 .217 .286 .064 .623 -.285 .432 -.096 .245 1

Cu .572 -.624 -.475 -.442 -.410 -.714 .002 -.523 -.243 -.546 -.845* 1

Zn .537 .181 .190 .080 .533 -.340 -.293 -.088 -.229 .228 -.116 .027 1

Cr CO \D -.110 .036 .020 -.435 .363 .870* .183 .727 .210 -.119 .079 -.564 1

Cd 6 CO .806 .744 -.150 .590 .706 -.230 .792 .202 .736 .700 -.684 .349 -.176 1

Hg -.365 .136 .023 .256 .533 -.323 -.355 -.256 -.291 -.078 -.163 -.146 .334 -.721 -.159 1

Pb .187 -.548 -.403 -.032 -.615 -.214 .674 -.342 .351 -.327 -.603 .565 -.615 .740 -.775 -.346 1

* Correlation is significant at the 0.05 level (2- tailed) ** Correlation is significant at the 0.01 level (2- tailed)

5.0 Conclusion

The leachate derived from the Dhapa municipal closed dumping ground demonstrates exceedingly high values for almost all the physico-chemical parameters. Except lead and mercury, all the heavy metals were present at the levels below their respective permissible limit in leachate. The influence of leachate percolation is evident on the surrounding groundwater. Most of the physico-chemical parameters of groundwater exceed their respective permissible limits. All other heavy metals except Pb and Hg were below the permissible limit, which may be due to the redox controls. Hg and Pb concentration in surface water samples were above their respective permissible limits. The extent of contamination of local water resources necessitate appropriate treatment of leachate before getting discharged and establishes the significance of post closure management of the closed dumpsite.

6.0 References

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