Leachate Pollution Index Research Articles

Comparison of Landfill Leachate Properties by LPI and Phytotoxicity-A Case Study

The formation of leachate is one of the inevitable consequences associated with the operation of landfills. In addition to the study of physicochemical composition, toxicity is an important parameter taken into account, among others because of the need to subject leachate to treatment before discharge into the environment. The aim of this study was to determine the degree of leachate contamination using LPI and toxicity index. An analysis of the relationship between the toxic effect on plants and the calculated LPI values was also carried out to assess whether they could provide a measure of leachate toxicity when selecting a treatment method. The research conducted was to determine the degree of leachate contamination using LPI and toxicity index. An analysis of the relationship between the toxic effect on plants and the calculated LPI values was also carried out to assess whether they could provide a measure of leachate toxicity when selecting a treatment method. Calculated values of the leachate pollution index showed that leachates from selected Polish landfills are characterized by low and medium levels of LPI values. The variation in index values obtained was particularly evident between active and closed landfills and was related to the physicochemical composition of leachates. In closed landfills this value ranged from 7.4 to 11.1, while in active landfills from 12.9 to 15.9. The variation in index values obtained was particularly evident between active and inactive landfills and was related to the physicochemical composition of leachates. Phytotoxicity tests showed that leachate at low concentrations can promote plant growth. At higher concentrations (50 and 100%), leachates caused inhibition of root and shoot growth, which correlated with high LPI values. The results confirmed the relationship between the toxic effect on plants and the LPI values, so it can be considered as a reliable indicator of leachate toxicity.

English

Environmental pollution leads to poor health and has been a worrisome experience to humanity for the past few decades. This research was conducted to determine the pollution potential of landfill leachates (LFL) in Sub-Saharan Africa, using Ibadan as case study. Survey of landfills in the metropolis was undertaken; the two major active unlined landfills (Ajakanga and Awotan), were considered for this study. During sampling, eighteen parameters of interest were analyzed. The leachate pollution indices (LPI) of each landfill were calculated. The LPI of Awotan landfill is 17.55 while that of Ajakanga is 15.67. With the exceedances of the 7.378 standard LPI value, all landfills in the metropolis is recommended to be closed down in line with international best practices and new sanitary landfills set up in their stead. Based on the sub-LPI values obtained, biological treatment would be the most viable treatment option for the LFL produced. The findings from this study are applicable in landfill management in other countries within the African sub-region; thereby contributing to the attainment of Sustainable Development Goals (SDGs). Key words: Leachate pollution index, landfill, sustainable development goals, Ibadan, Nigeria, assessment.

Proposed formulations for error reduction in leachate pollution index (LPI) estimation due to the absence of leachate parameters

The applications of leachate pollution index (LPI) as an environmental index to express the overall leachate-contaminating ability of landfills are increasing. Majority of these applications wrongly quantify LPI due to the absence of various leachate parameters. The traditional linear weighted aggregation equation used in LPI estimations, result in larger errors as missing parameters increase. In this article, error reduction equations were established to predict LPI values more accurately. Approximately 1797 unique combinations of leachate weights ( ∑ wi) were randomly assigned to cover the missing parameters and augment the accuracy of the proposed error reduction equations. The upper and lower boundaries of LPI were accurately estimated in each case, starting from 1 missing parameter to 12 missing parameters. Various linear equations were generated, when possible, to ease the calculations. Subsequently, the arithmetic, geometric, and harmonic averages were applied between the LPI limits in five different case studies to demonstrate the validity of the developed error reduction equations. These equations were capable of providing reliable LPI values even when up to twelve leachate pollutants were absent. It was found that the harmonic average was the best average to be applied between the LPI boundaries, which mostly resulted in errors around ± 20% for ∑ wi values up to 0.3. • Modified LPI formulations for error reduction of leachate pollutants absence. • Random data generation was applied to cover most possible LPI combinations. • Harmonic average outperformed peer arithmetic and geometric averages. • Reliable values of LPI can be estimated mostly with errors up to ± 20%.

Need for Reassessment of Environmental Indices

Several environmental indices have been developed over the last five decades. These indicators have been used by decision makers. However, it is becoming difficult for decision makers to understand the relevance and meaning of these indicators because of factors, such as technological advancement, reliability of these indicators over time, the emergence of new parameters, and suitability of these indices that have posed questions on the relevance of these indicators. Therefore, revalidation or reassessment of the environmental indices is required. In this paper, a case study on the leachate pollution index (LPI) that was developed using the Delphi technique will be conducted. The procedure that was used for the development of the index did not accurately reflect the opinion of the experts that have responded to the questionnaire. In addition, shortcomings in the formulation of the LPI are highlighted and, based on this paper, it was concluded that if the correct procedure was adopted, the LPI might contain different parameters as constituent pollutants. Therefore, this paper highlights the need to reassess environmental indices.

Characterizing Seasonal Variation in Landfill Leachate Using Leachate Pollution Index (LPI) at Nam Son Solid Waste Landfill in Hanoi, Vietnam

The improper treatment of landfill leachates is one of the major problems associated with waste landfilling and causes serious environmental pollution at waste landfill sites and their surroundings. To develop a suitable landfill leachate treatment system and to minimize the risk of environmental pollution, it is important to characterize seasonal and temporal variations of landfill leachates. This study investigated the leachate quality of the Nam Son waste landfill in Hanoi, Vietnam in 2017–2019 and characterized the potential risks of landfill leachate using a leachate pollution index (LPI). The results of this study showed that the seasonal and temporal variation of the overall LPI during the monitoring period was small and in the range of 20–25 (values 2.5 times higher than the maximum permissible limits of Vietnam National Technical Regulation on Industrial Wastewater). The LPI sub-indices attributed to organic and inorganic pollutants were major components of the LPI. Especially, the annually averaged values of LPI of inorganic pollutants were 7.7 times higher than the maximum permissible limits, suggesting that the treatment of inorganic pollutants, such as ammonium-nitrogen (NH4+–N) and total nitrogen (TN), is highly required at Nam Son landfill to prevent environmental pollution surrounding the landfill site.

Temporal variation of leachate pollution index of Indian landfill sites and associated human health risk.

The present study investigated the variation in leachate pollution index (LPI) of four municipal solid waste (MSW) dumping sites: non-engineered (Okhla, Ghazipur, Bhalswa) and engineered (Narela-Bawana) of Delhi, India. A review of 142 screened studies from Google Scholar database was done for synthesis of information on LPI parameters. Further, the rate constant determination and human health risk assessment for various leachate parameters was done. Results showed the following LPI trends: Okhla landfill: irregular with exceedance to threshold value; Bhalswa landfill: exponential increase; and Narela-Bawana landfill: linear increase. Parameters such as pH, dissolved solids, copper, nickel, zinc, and chromium of Bhalswa landfill, exhibited an exponential decay with LPI variation. Whereas, for Narela-Bawana's leachate BOD and COD parameters, an exponential decay in LPI vs zinc and linear increase for LPI vs lead was observed. For all dumping sites, a positive correlation was observed between heavy metals and LPI. In case of human health risk assessment, order of oral risk posed by Okhla's metals was cadmium > chromium > nickel > lead, with maximum hazard quotient (HQ) of 1.61 for cadmium. For Ghazipur and Bhalswa landfills, cancer risk values for both adult and child sub-populations were observed to be maximum for cadmium followed by nickel, chromium, and minimum for lead. For Narela-Bawana landfill, the order of cancer risk was as follows: chromium > nickel > lead. HQ for Pb-contaminated groundwater exceeded the threshold limit in Ghazipur and Bhalswa landfills. For dermal groundwater exposure, cadmium for Okhla (adult 2.3 × 10-4 and child 1.4 × 10-4), Ghazipur (adult 9 × 10-5 and child 5.2 × 10-5), and Bhalswa (adult 1.5 × 10-4 and child 8.6 × 10-5) was observed to have maximum cancer risk. The analyzed year-wise LPI trend, calculated rate constants, and human health risk values from present study provide a basis to waste managers and regulators for understanding various waste sources.

Evaluating the leachate contamination impact of landfills and open dumpsites from developing countries using the proposed Leachate Pollution Index for Developing Countries (LPIDC)

The Leachate Pollution Index (LPI) was formulated in 2005 to evaluate the pollution potential of landfill leachate, so that better strategies can be implemented to prevent continuous environmental degradation. As leachate characteristics are dependent on the waste composition, which is notably different between developed and developing countries, the LPI cannot be used to accurately evaluate leachate from all over the world. Hence, using the LPI as a benchmark would yield inaccurate conclusions on the severity of the pollution of these leachates. To address this, we developed an index that is more accurate in determining the pollution impact of leachate in developing countries; The Leachate Pollution Index for Developing Countries (LPIDC). LPIDC was developed after consulting various experts in waste management based in developing countries, who shared their expertise, knowledge and experience to identify parameters that needed to be assessed when evaluating the pollution potential of leachate. To determine the precision of LPIDC, we analysed leachate samples from Malaysian landfills and open dumpsites, and also reviewed leachate data from other developing countries. We then used the data to compare the precision of LPI and LPIDC. The data confirmed that LPIDC provided a more precise evaluation of the pollution impact of leachate in developing countries. This is due to the LPIDC taking into account several important parameters that were overlooked in the LPI, namely landfill liners and leachate volume.

Anammox, biochar column and subsurface constructed wetland as an integrated system for treating municipal solid waste derived landfill leachate from an open dumpsite

This study aims to treat nitrogen-rich landfill leachate from Karadiyana open dumpsite, Sri Lanka, through an integrated treatment train consists of an anammox process, Municipal Solid Waste derived biochar column followed by a biochar embedded subsurface constructed wetland. Characterization of leachate was done and the leachate pollution index (LPI) was estimated. Meanwhile, leachate was treated through a treatment system comprising an anammox reactor having 140 mm diameter and 250 mm height, a biochar reactor having the same dimensions with 1.3 kg of MSW biochar, and a laboratory-scale constructed wetland of 1 × 0.3 × 0.45 m. The influent and effluent quality was assessed for the samples taken in 24 h intervals. The analysis indicated that the leachate was high in COD (4000–14,000 mg/L), ammonia (760–900 mg/L), nitrate (60–126 mg/L), and phosphorus (33–66 mg/L). Ammonia and nitrite were removed 94 and 99% by anammox unit, respectively. Nitrate, phosphate, COD and conductivity were significantly removed by the constructed wetland system in 78, 70, 65 and 61%, respectively, whereas biochar barricades extended support for removal of the contaminants and color. The combined treatment system demonstrated treatment efficiencies as 100% of ammonia, 98.7% of nitrite, 98.2% of nitrate, 80.9% of phosphate, 79.7% of COD, and 69.9% of conductivity. Thus, it can be concluded that the anammox, combined with biochar embedded treatment train is promising to treat landfill leachate, having a high pollutant index.

Geostatistical Modelling of Groundwater Quality at Rumuola Community, Port Harcourt, Nigeria

The groundwater quality of Rumuola community of Rivers State, Nigeria was investigated. This study was done to determine the pollution potential of a solid waste open dump in a borrow pit in the community. The leachate pollution index was calculated for the borrow pit at the centre of the community using weighted additive leachate pollution index. The result showed that the LPI value was 5.31 and has low pollution potential. It was discovered that the groundwater in the entire community was acidic with pH levels ranging from 3.6 to 4.2, which is below NSDWQ’s permissible range of 6.5-8.5. Nickel and arsenic also showed concentrations that were above permissible limits with nickel values averaging 0.033 mg/l which is slightly above the limit of 0.02 mg/l. Arsenic had concentrations that ranged from 0.16 to 1.57 mg/l which is above permissible limits of 0.01 mg/l. WQI was determined using weighted arithmetic water quality index analysis. As a result of the high concentrations of arsenic, the WQI values were very high with values ranging from 144 to 1367 and this shows that the water in the study area is unsuitable for drinking. In modelling the water quality index of Rumuola community, geostatistical methods were applied. Ordinary kriging, Empirical Bayesian kriging (EBK), inverse distance weighting (IDW) and cokriging interpolations methods were used to produce surface maps showing the distribution of variables using ARCGIS software. The best interpolators were: EBK for pH, TDS, Sulphate and nitrate; Ordinary kriging for Nickel and Hardness; IDW for Iron and arsenic; Cokriging for WQI.

Assessment of Age Effect of Dumpsite on Biodegradability and Pollution Potentials of Leachate

The increase in world’s population has led to increase in waste generation and is a source of concern for stakeholders across the world. These wastes end up in dumpsites which undergo different stages of decomposition thereby producing Leachate which have a tendency of polluting groundwater. This study assessed biodegradability and Leachate Pollution Index (LPI) of dumpsite relative to its age. Three dumpsites Orile (O), Solous 3 (S3) and Solous 1 (S1) dumpsites with different ages: – less than 5, between 5-10 and greater than 10 years old respectively were studied. Leachate samples were collected from each dumpsite; Physico-chemical parameters: pH, chloride, Iron, Zinc, Arsenic, Total nitrogen, Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Total Dissolved Solid, Electricity Conductivity and heavy metal: Lead, Chromium and Copper were analysed to determine the LPI while BOD5/COD was determined to ascertain the level of biodegradability of the dumpsites. The BOD5/COD results for O, S3 and S1 leachates were in the decreasing order of 0.37, 0.29 and 0.21 respectively while LPI results for: O, S1 and S3 leachate were 10.00, 11.20 and 15.68 respectively which were above the standard limit of 7.38. The results showed that O and S1 dumpsite leachate had least and highest sign of biodegradability respectively. The LPI result showed that O and S1 dumpsite leachates had the highest and the least pollution potentials respectively. Leachate from dumpsites less than 5 years has higher pollution potentials and lesser biodegradable than leachates from dumpsites more than 5 years. Leachate from O dumpsite will impact negatively on groundwater quality than leachates from S1 and S3 dumpsites. The age of a dumpsite leachate determines its pollution potential and biodegradability.

Leachates From Landfill Sites In Thessaloniki, Greece: Effect Of Aging

Sanitary landfilling still is one of the most common management systems of solid urban wastes. The persistent environmental impact of landfills depends on leachate characteristics. The present study aimed at the characterisation of leachate from two landfill sites in the prefecture of Thessaloniki, Greece. Mavrorachi landfill stands in our study as a representative Greek active landfill site, that started operating in 2008. Tagarades landfill has stopped receiving waste from 2008 after 27 years of full operation. In this investigation, leachate samples were physico-chemically characterised so as to assess their pollution potential and their concentration in regard to the type and age of landfill. Elevated concentrations of inorganic and organic constituents were observed in the leachate composition. COD ranged from 2,490 mg/L to 19,700 mg/L, while the respective range for BOD was 390-14,850 mg/L during a 35-year period. The pH values of the leachate samples presented more moderate fluctuations between 7.3 and 8.5. In addition, the ammoniacal nitrogen content increased as landfill age increased, whereas heavy metals concentrations showed significant variations with a slight decreasing trend. The results presented in this paper proved that as time passed, the values of most parameters decreased as the biodegradable compounds are broken down while the refractory compounds resist to biodegradation. Thus, the age has a pronounced influence on the composition of leachate. This study also focused on quantifying the level of contamination that leachates can be potentially cause on a comparative basis by Leachate Pollution Index (LPI). LPI values showed that pollution load was declining but is still not negligible after 33 years.

Treatment of urban municipal landfill leachate utilizing garbage enzyme

In the present study, an attempt has been made to extend the application of garbage enzyme (GE) (fermented mixture of jaggery, organic waste, and water in the ratio 1:3:10) from the domestic wastewater to the urban municipal landfill leachate of Ghazipur, Okhla and Bhalswa landfill sites of Delhi (India). The Leachate Pollution Index (LPI) has been found to be 27.6, 25.4 and 29.2, respectively. The competence of GE was assessed by comparing the initial and final LPIs. The GE was added to the leachate for the contact period of 7–28 days under different mix proportions of 5%, 10%, 15%, and 20%. The maximum final LPI reduction of 74.75% was observed in the Okhla landfill leachate for mixing the proportion of 20% GE after 28 days. However, the mixing ratio of 5% GE showed significant reduction of 60.61% and 55.12% in the final LPI of Ghazipur and Bhalswa landfill leachate, respectively.

A Comparative Study on the Effects of Leachate on Groundwater in Selected Dumpsites in Rivers State, Nigeria

The health and environmental risk associated with unlined open waste dumpsites are worrisome. This study, therefore, evaluated the leachate and its final fate on groundwater pollution at selected solid wastes dumpsites in Rivers State. Leachate samples collected near the dumpsites were analyzed to determine the physical and biochemical characteristics. The two studied dumpsites indicated that the computed TCB were 296.33±6.22 cfu/100 ml and 182.68±21.33 cfu/100 ml respectively which were within the permissible limits of 400cfu/100 ml specified by World Health Organization (WHO) and Federal Ministry of Environment (FMEnv); which suggest low quantities of disease-causing agents in the groundwater. The total heterotrophic bacteria (THB) were 21x104 cfu/ml and 17x104 cfu/ml. These high values of THB may not be an indication of contamination of groundwater but it indicates a gradual decline in raw water quality. The values of SO42-, PO43-, TDS, DO, BOD and COD at the dumpsites were 196.52±6.26 mg/l and 9.12±0.59 mg/l, 139.23±3.19 mg/l and 3.81±0.68 mg/l, 5952.23±72.52 mg/l and 12663.33±490.95 mg/l;1.51±0.42. mg/l and 2.02±0.16 mg/l; 31.22±4.12 mg/l and 21.33±3.51 mg/l, and313.30±6.57 mg/l and 270.33±26.16 mg/l respectively which exceeded the standards of the WHO and FMEnv. The high values of analyzed parameters were an indication of the groundwater contamination. Heavy metals in the Rumuosi dumpsite indicated 11.31±1.33 mg/l, 11.01±0.67 mg/l, 361.84±12.31 mg/l, 118.03±5.74 mg/l and 84.77±4.84 mg/l for Pb, As, Mn, Fe and Zn respectively. While Heavy metals thresholds at Igwuruta were 0.004±0.005 mg/l, 0.04±0.07 mg/l, 0.05±0.08 mg/l, 0.08±0.14 mg/l and 0.15±0.04 mg/l respectively. Rumuosi thresholds exceeded the standards, indicating that the exposed local people in the nearby communities may experience cases of non-carcinogenic and carcinogenic health risk by drinking the groundwater. The leachate pollution index (LPI) at the studied dumpsites indicated 13.58 and 12.9 which exceeded the internationally accepted benchmark of 7.38; indicating that the Rumuosi leachate was more polluted than Igwuruta leachate. The analysis of variance (ANOVA) of the pollutant characteristics indicated a significant difference at p=0.05 across the physicochemical and biological indicators at Rumuosi dumpsite over Igwuruta dumpsite. The researcher recommended the practice of sanitary landfill which may reduce the risk of leachate percolation, a primary source of groundwater contamination.

Impact of Municipal Solid Waste Landfill leachate on groundwater quality in Varanasi, India.

This study assesses the impact of municipal solid waste (MSW) landfill leachate on its surrounding groundwater quality of village Ramna, Varanasi, India. Leachate pollution index (LPI) of landfill leachate was evaluated with their physicochemical analysis that represents the overall leachate pollution potential and hazardous nature of MSW leachate. Physicochemical analysis of groundwater quality around the landfill site does not favour to drinking and domestic purposes as per the WHO and BIS standard. A considerable amount of NO3−, PO43−, Fe, electrical conductivity (EC) and total dissolved solid (TDS) were found in the groundwater samples near to the landfill site especially during post-monsoon, indicating that groundwater quality is being significantly affected by leachate percolation. Factor analysis signifies positive loading of most of the toxic pollutant that presenting MSW leachate impact on groundwater quality. WQI results also revealed that most of the groundwater samples were deteriorated from good and excellent water quality in pre-monsoon to fair water quality in post monsoon near the landfill site. Groundwater flow modeling simulation also showing that increase in the hydraulic head during the post-monsoon responsible for the downward flow of leachate pollutants from the landfill site. This Study suggests an urgent need for the sanitary landfill to control and minimize the impact of MSW leachate on groundwater quality around the Raman MSW landfill site.

Leachate characterizations and pollution indices of active and closed unlined landfills in Malaysia

Leachate is one of the most serious environmental hazards associated with landfills especially which are unlined and uncontrolled. Thus, this study aims to characterize and compare raw leachate from active landfills (Ulu Maasop and Kampung Keru) and closed landfill (Pajam), then subsequently quantify the potential leachate contamination from each landfill using Leachate Pollution Index (LPI). The results obtained from the current study were compared with data from previous publications and indicated higher physico-chemical characterizations, especially for BOD and COD, than that of the other similar landfill categories. Based on the current findings, the low ratio of biodegradability and slightly alkaline pH values in leachate samples indicated that the sites (both active and closed landfills) were characterized by methanogenic conditions. Moreover, heavy metal concentrations, Cr, Fe and Se levels were higher than the leachate discharge standards for all leachate sampling sites. The As, Cu, and Mn, also surpassed the leachate discharge standards for the active landfill sites tested in this study (Ulu Maasop and Kampung Keru landfills). Next, the LPI calculated for Ulu Maasop, Kampung Keru, Pajam (1 and 2) landfills were 15.28, 13.89, 12.91 and 11.51, respectively, all exceeding the LPI for discharge standard of 5.696. Based on the leachate characterizations and the LPI values, these landfills pose a significant threat to the environment through the dissipation of leachate to the surface and groundwater, especially with the presence of BOD, COD, As and Cr. Thus, remedial actions such as rehabilitation of such unlined landfills and post-closure monitoring are crucial for both active and closed landfills to ensure the generated leachate is stabilized. Such actions will reduce and control the threat to the environment.

Rural solid waste-characteristics and leachate pollution assessment for different precipitation levels, China.

Open dumping adversely affects the environment and remains the most widely used method for waste disposal in many developing rural areas in China. Information regarding the impact of rural solid waste (RSW) on the environment remains limited. The objectives of this study are to investigate the characteristics of RSW and the impact of different precipitation rates, and to evaluate the contamination potential of RSW using a leachate pollution index (LPI). The study showed that leachate concentration was significantly influenced by precipitation rates at the initial precipitation stages. Precipitation rates of 42.00mm/day appeared to have the largest dilution effects. In contrast, the concentrations of leachate at rainfall rates of 24.00mm/day and soaking were steady, and no similar trends were observed. The highest amounts of pollutants in leachate were the result of soaking. In the first week of our experiment, the LPI value for each rural area waste sample rapidly increased with rising precipitation rates from soaking to 42.00mm/day. However, no significant change in LPI was observed thereafter (after 5weeks) even with increasing precipitation rates. The values of chemical oxygen demand, biochemical oxygen demand, total nitrogen, and NH3-N in the leachate after 10weeks were 4.00, 7.34, 1.87, and 2.21 times higher, respectively, than those of the prescribed leachate quality standards in China. The results of our study suggest the following course of action for the three dump sites investigated: in Banqiao, given the size of the population and the size of the waste amount, landfill might be a suitable way for disposing of RSW. In Machen, building a standardized waste collection site would be an economical solution for reducing potential pollution risks. In Jiuduhe, increasing the transportation rate of solid waste might be an effective solution. The results of this study can help to improve the understanding of leachate pollution in Chinese rural areas.

Assessment of groundwater pollution by landfills in India using leachate pollution index and estimation of error

Unsystematic dumping of municipal solid waste affects soil, water and air by generating leachate, which effects the environment and human health. Considering this, present study investigates the leachate pollution index (LPI) of Indian landfills using leachate characteristics already published and by calculating the physico-chemical characteristics of landfill leachate from Chandigarh, SAS Nagar and Panchkula cities. LPI is a grade system (ranging from 5 to 100), which represents the capacity of leachate to contaminate the ground water through subsoil. Calculation of LPI shows that most of the Indian landfills have higher LPI than the acceptable limit (7.378). The error involved in LPI calculation was also studied using tricity (Chandigarh, SAS Nagar and Panchkula) LPI data. Higher sub-index and lower sub-index parameters were considered for error analysis. According to the results, ignoring higher sub-index parameters increases the error 79.2%, 68.5% and 67.8% in Chandigarh, SAS Nagar and Panchkula respectively. Whereas, LPI of landfills decreases 5 in Chandigarh, 7 in SAS Nagar and 5 in Panchkula. Based on the current study, It was observed that LPI values of Chandigarh, Mohali and Panchkula during pre- monsoon were 33.18, 26.17 21.94 and during post monsoon were 25.5, 20.32 and 19.49 respectively. it can be inferred that landfill leachate in India has significant potential to contaminate the groundwater resources. Considering this, the study also discusses some suitable remedial measures to reduce the ground water pollution by landfill leachate and demands more policy intervention to reduce the environmental and human health impact of MSW landfills.

Impact of non-engineered Bhalswa landfill on groundwater from Quaternary alluvium in Yamuna flood plain and potential human health risk, New Delhi, India

The unplanned Bhalswa landfill is located in one of the most urbanized area of Delhi, and its influence on the huge population are inevitable in the capital city of India lying in flood plain of the Yamuna River, and its alluvial lithology makes it more susceptible to contamination by leaching of pollutants. The present study highlights to assess the impact of non-engineered Bhalswa landfill site on the groundwater quality and associated potential health risk by its consumption to local residents of New Delhi, by collecting four leachate and sixty groundwater samples for pre- and post-monsoon seasons in the year 2013. The contamination potential of the leachate samples and the groundwater quality were evaluated with the help of leachate pollution index (LPI) and water quality index (WQI), respectively. The value of LPI is high in both the seasons but more in pre-monsoon (31.51) as compared to post-monsoon (29.36). The Obtained results of groundwater samples showed elevated level of Electrical conductivity (EC), major cations and anions. The EC of groundwater samples display concentration as follows: (pre-monsoon, 456–10870, average 3772; post-monsoon, 465–10450, average 3747). The groundwater samples close to the Bhalswa landfill shows very high value of EC and other chemical parameters. WQI calculated (using 17 physico-chemical parameters and WHO standards) to distinguish the areas of excellent and unsuitable for drinking purposes which will be helpful for the management of water resources. Our results showed that the concentration of majority of heavy metals exceed the WHO permissible limit except Cr and Cu which may be due to redox conditions that control the mobility of these ions in aqueous solutions. The average target hazard quotient (THQ) value of heavy metals were found in the order of Cd > Mn > Pb > Cu > Ni > Fe > Zn > Cr in both the seasons. The tube wells with more than one THQ value for Cd (100%), Mn (63%) and Pb (37%) will have potential human health risks. Hazard index (HI) shows greater than one value for all the samples and the average HI values are 10.241 for pre- and 10.402 for post-monsoon season. THQ and HI values suggest that the residents are highly susceptible to ingestion pathway. A conceptual model is used to describe the dispersal of leachate pollutants with reference to various kinds of geo-environmental features which degrades the groundwater quality. The health risk associated with metals in near future can be a serious threat for this region if this groundwater is being used for long run without proper remedial measures.

Assessment of groundwater quality using WQI and GIS near the Karsara municipal landfill site, Varanasi, India

The present paper reports the evaluation of the groundwater quality around the municipal landfill site in Varanasi City, Uttar Pradesh, India. Leachate pollution index (LPI) and water quality index (WQI) have been used to determine the quality of leachate of landfill and groundwater in the study area. LPI value (16.81) of landfill leachate revealed the presence of significant amount of the pollutants. WQI of groundwater samples near the landfill site has been calculated and water quality map has been prepared by using WQI in GIS environment for both pre- and post-monsoon periods of the year 2016. Results of WQI revealed that 35% groundwater samples are good, 35% marginal, 20% excellent, and 10% are in fair category in pre-monsoon period while in post-monsoon 70% samples are marginal, 15% excellent, 10% fair, and 5% are in good category. WQI map shows that most of the study area near the landfill site is in fair category during pre-monsoon season but in threatened category during post-monsoon season. The results of the physicochemical analysis of groundwater have shown that the water is not safe for drinking purpose as some parameters like TDS, hardness, total alkalinity, and nitrate and iron content were observed to be above the acceptable limit (WHO and BIS) of drinking water quality. This study revealed that WQI and LPI can also be an important monitoring tool for landfill policy makers and the public to safeguard groundwater pollution risk from the landfill.

Indexing method for assessment of pollution potential of leachate from non-engineered landfill sites and its effect on ground water quality.

Dumping of solid waste in a non-engineered landfill site often leads to contamination of ground water due to leachate percolation into ground water. The present paper assesses the pollution potential of leachate generated from three non-engineered landfill sites located in the Tricity region (one each in cities of Chandigarh, Mohali and Panchkula) of Northern India and its possible effects of contamination of groundwater. Analysis of physico-chemical properties of leachate from all the three landfill sites and the surrounding groundwater samples from five different downwind distances from each of the landfill sites were collected and tested to determine the leachate pollution index (LPI) and the water quality index (WQI). The Leachate Pollution Index values of 26.1, 27 and 27.8 respectively for landfill sites of Chandigarh (CHD), Mohali (MOH) and Panchkula (PKL) cities showed that the leachate generated are contaminated. The average pH values of the leachate samples over the sampling period (9.2 for CHD, 8.97 for MOH and 8.9 for PKL) show an alkaline nature indicating that all the three landfill sites could be classified as mature to old stage. The WQI calculated over the different downwind distances from the contamination sites showed that the quality of the groundwater improved with an increase in the downwind distance. Principal component analysis (PCA) carried out established major components mainly from natural and anthropogenic sources with cumulative variance of 88% for Chandigarh, 87.1% for Mohali and 87.8% for Panchkula. Hierarchical cluster analysis (HCA) identifies three distinct cluster types for the groundwater samples. These clusters corresponds to a relatively low pollution, moderate pollution and high pollution regions. It is suggested that all the three non-engineered landfill sites be converted to engineered landfill sites to prevent groundwater contamination and also new sites be considered for construction of these engineered landfill sites as the present dumpsites are nearing the end of their lifespan capacity.