pH is the paramount index of water quality and is considered as an aesthetic quality criterion. The pH level of water courses is critical for the endurance of water inhabiting living organisms. Aquatic life is responsive to variation in pH. The optimum pH for fishes sweeps from 6.5 to 9. Outside the optimum range fishes become prone to defiling from noxious substances. Variation in pH is also accountable for overabundance of available plant nutrients, leading to enhanced growth of plants and reduction of oxygen concentration for fishes (Judith, 2019). In the current research pH of water was recorded maximum at leachate outflow site (7.9), followed by 900m downstream (7.4), 1500m downstream (7.2) and lowest was recorded at 300m upstream (control site) (6.7) during all the seasons as depicted in (Table 1). The overall maximum mean water pH was found at leachate outflow site during summer season (8.4) and the lowest was noted at control site during winter season (6.0). Among sites, the highest mean pH value was noted at leachate outflow site and lowest was found at control site, the maximum pH at leachate outflow site may be because of presence of huge amount of exchangeable bases present in the leachate. Whereas with reference to seasons, maximum mean water pH was observed during summer season (7.9) and lowest was during winter season (6.6) as depicted in (Fig. 2) which may be because of equilibrium between acid generating activities viz breakdown of cellulose and lignin and acid utilizing activities viz methane production from landfills under anaerobic conditions. The variation of pH has deleterious effects on aquatic organisms as these organisms can accommodate in an average pH and are not able to resist sudden change in pH (Mini, et al., 2003). High as well as low pH of water can be deleterious for utilization. Water with high pH has acrid taste and the chlorine sterilization efficacy of water gets reduced, thereby increasing the requirement of chlorine. Also with elevation in pH concentration of oxygen also increases. Low-pH corrodes as well as dissolves metals and other materials. Thus any change in pH damages aquatic plants and animals [APHA, 2005]. It has been reported that slightly acidic water can reduce the figure of hatched eggs in fish, irk the gills of aquatic organisms, and destroy membranes [Kiprono, 2017]. Ammonia is comparatively inoffensive in neutral or acidic water than alkaline water to fishes.
Conductivity can be described as the tendency of water to conduct an electric current and gives indirect estimation of saltiness of the water. Living organisms inhabiting fresh water are not capable to stand increase in saltiness of water due to the inability to hold water in their bodies. In this study EC value was recorded maximum at leachate outflow site (2.15), followed by 900m downstream (1.32), 1500m downstream (0.64) and least was recorded at 300m upstream (control site) (0.45). With respect to seasons, the maximum mean EC was recorded during summer season (2.35) given in (Table 1), which may be because of high ionic load and release of organic and inorganic components from leachate (Archana, and Dutta, 2014). The minimum value of EC was recorded during winter season (0.50). Among sites the mean maximum EC recorded at leachate outflow site may be because of presence of concentrated leachate. Further with increase in distance from the leachate outflow site EC shows decreasing trend depicted in (Fig. 3), which may be attributed to decrease in ionic concentration due to dilution (Archana, and Dutta, 2014).Huge concentration of ions in water may be because of presence of dissolved solids. Increase in conduction and positively charged ions are the outcome of disintegration and mineralization of animate substances (Abida, 2008).The minimum value of EC was recorded during winter season because of diminish in concentration caused by precipitation like rain and snowfall. Escalation in conductivity is regarded as indicator of an increase in quantity of polluting substances.
Turbidity is the measure of how cloudy or murky water is, and is created by scattering of molecules suspended or dissolved in it. Particulate matter includes sediments especially clay and silt, fine animate and inanimate matter, soluble colored organic compounds, algae, and other microscopic organisms (Paaijmans et al., 2008). In this study Turbidity showed the same pattern as pH and EC as shown in (Table.1). Among sites turbidity was recorded maximum at leachate outflow site (14.28) and showed decreasing trend with increase in distance from leachate outflow site. This decrease in turbidity with increase in distance might be attributed to dilution effect and settling of suspended matter (Srivastava et al., 2011). Among seasons maximum turbidity recorded during summer season (8.49) may be because of clay, silt, organic and inorganic substances as organic matter enhances the propagation of microbial groups and inorganic components like nitrogen and phosphorus enriches the water body and promotes algal bloom that extent to escalate the turbidity and minimum was recorded during winter (5.31)(Mandal, 2014). The high turbidity levels due to leachate reduces the photosynthetic activity of organisms thereby affecting the survival of phytoplankton and other green algae communities (Hussein et al. 2019)
The extreme amount of nutrients, mostly nitrogen (N) and phosphorus (P), is a fundamental component in hastening the eutrophication of water courses by boosting the biological activity (Gurkan et al. 2006; Dupas et al. 2015). Agricultural and urban areas are source of majority of these elements. Release of unprocessed refuse into water courses is the principal reason of enhancing eutrophication in developing countries (Beyene et al. 2009). In this study Total Nitrogen was recorded highest at leachate outflow site during summer season (3.55) which may be because of dominance of organic nitrogen in leachate which is released due to degradation of proteins, amino acids, urea, dead and decaying organisms, and excrement by organisms, including livestock manure and human wastes. However minimum quantity was recorded during winter (1.11) as depicted in (Fig. 4). Which may be due to less degradation of organic nitrogen rich components (Wall, 2014). Among sites maximum total nitrogen was recorded at leachate outflow site (2.63) which decreased with increase in distance from leachate out flow site (Table 2). This decrease in total nitrogen with increase in distance may be because of transformation of organic nitrogen into nitrate which is utilized by macrophytes (Wall, 2014). Total nitrogen is beneficial nutrient for both plants and animals but its high concentration in a water body may decrease the dissolved oxygen and negatively alter various organisms. Same trend was observed for phosphorus. The maximum mean phosphorus concentration was recorded during summer season (3.99), which may be because of low oxygen conditions, low oxygen conditions favour degradation of phosphorus leading to the release of phosphorus in dissolved and deftly attainable form, while as minimum concentration recorded during winter (2.73) may be due to deposition of phosphorus compounds in sediments (Kroiss, et al., 2015). Among sites maximum mean phosphorus concentration recorded at leachate outflow site (4.75) may be attributed to the fact that leachate carries substantial quantity of phosphorus and minimum was recorded at control site (2.55) (Table 2) and Fig. 5. Potassium was also maximum recorded during summer season (0.89), which may be because of high degradation of organic materials such as kitchen and agricultural wastes and the decomposition of inanimate refuse like concrete, plaster and tiles (Hiremath, and Naik, 2018; Naveen, et al., 2014). While as minimum concentration was recorded during winter (0.54). Among sites maximum K concentration was recorded at leachate outflow site (1.41), which may be because of high concentration of leachate. There is a common reduction in K concentration with increase in distance from the leachate outflow site as shown in Fig. 6. This decline may be due to dilution effect.
Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) are two uncomplicated variables utilized to estimate organic matter constituting compounds. BOD is a criterion method for analyzing the oxygen-requiring concentration of microbes to deteriorate organic matter over a certain interval of time, commonly 5 days but can be expanded to 30 days. COD is a criterion method for water to utilize oxygen in the form of potassium dichromate during the decomposition of animate and inanimate substances such as ammonia and nitrite for few hours. The potassium dichromate is not particular to oxygen-utilizing chemicals either animate or inanimate and hence, both chemicals are involved in COD. The proportion of BOD/COD should be equal to or less than 1.0. Thus this proportion of BOD/COD is utilized to delineate biodegradable potential of materials by which organic matter composing wastewater is quickly decayed in the environment (Samudro and Mangkoedihardjo, 2010). In this investigation the mean maximum value of BOD was observed at leachate outflow site (21.46) may be due to richness of organic matter and much bacterial load (Maqbool et al., 2011) and minimum was recorded at control site (300m upstream) (13.02) as shown in (Table 5). Among seasons maximum BOD recorded during summer season (22.81) as shown in (Fig, 7) may be because of high degradation of organic waste due to favourable environmental conditions viz high temperature and high microbial load in the leachate disposed off in the water body. However minimum was recorded during winter (8.24), which may be attributed to little biotic action as majority of the microbes entailed in degradation of organic matter cannot persist at low temperature. COD represents the quantity of oxygen requisite to entirely oxidize the biotic refuse constituents chemically to inanimate final products (Bhalla et al., 2013). It measures the susceptibility of organic and inorganic substances in water to oxidation (Reza and Yousuf, 2016). Thus, COD is an authentic variable for deciding the degree of contamination in water (Amirkolaie, 2008). COD values are always greater than BOD values (Vaishali and Punita, 2013). In the current investigation the mean maximum value of COD recorded during summer season (65.87) may be because of increase in the amount of organic matter and minimum recorded during winter (32.63) as shown in (Fig. 8)may be because of low degradation rate. Thus, the high BOD5 found in water body due to leachates is expected to create greenhouse gas (GHG) emissions if the landfill situation is not revamped (Naveen et al. 2017). The BOD5 increases with high microbial activity.
Temperature of water greatly impacts the geological distribution of a species (Bell, 2006) and variation in water temperature results in variation in the richness, compactness, biomass, diversification and constitution of aquatic communities. It also influences life history cycles of aquatic insects, like Voltinism (the frequency of annual broods of a specific species), extent of coexistence, fidelity and rigidity of arrival, and resiliency (Dallas, 2009). The variation in atmospheric temperature is pro rata to that of water temperature. Both air and water temperature shows an increasing drift from winter towards summer, however air temperature is always more than the surface water temperature because of the fact that water molecules are held together with powerful hydrogen bonds and therefore can absorb large quantity of heat without escalation in temperature. The maximum temperature recorded during summer season (18.98) may be because of increase in air temperature (Mandal 2014) and minimum was recorded during winter (5.08), which may be ascribed to cool, less atmospheric temperature and short term photoperiods (Ganai and Praveen, 2014). Among sites mean maximum temperature recorded at leachate outflow site (14.21) as shown in (Fig. 9) may be because of suspended particles including organic as well as inorganic compounds (Mandal, 2014).
A number of research studies have suggested the association of a protective or beneficial effect of water Ca and Mg with chronic diseases including neurological disruption, amyotrophic lateral sclerosis, preeclampsia in pregnant females, increase in blood pressure, metabolic syndrome (Rosborg and Kozisek, 2020). Deficiency of Ca or Mg in quaffing water sounds to bring about decrease in bone mass density, greater chance of fractures, and diffused bone growth in children (Huang et al., 2018, 2019). On the other hand, water with very high levels of Ca and Mg may lower acceptability of the water due to taste, and together with high level of TDS may increase the risk of renal and other types of stones and arthritis problems. Water with high Ca levels is susceptible to cause scaling, and water with very high Mg levels, together with high 97 sulphate, causes transient diarrhoea (Rosborg and Kozisek, 2020). Also these two elements are associated with hardness of water (Naveen et al., 2018). Most often Ca is observed in divalent state in water. Shells of water inhibiting organisms and bones of vertebrates are composed of calcium. Generally Ca is detected in all natural waters, but the concentration is increased by discharging sewage and wastewater (Sudarshan et al., 2019). During the present study, Ca ranged from 43.06 to 114.40 (mg/Kg) as shown in (Table 3). Among seasons the maximum mean Ca concentration recorded during summer season (85.93) may be because of enhanced degradation of calcium rich substances like bones, teeth, eggshells etc and minimum was recorded during winter (63.85). Ca concentration followed decreasing trend with increase in distance from leachate outflow site. This may be due to its retention by macrophytes and accumulation in bottom deposits (Potasznik and Szymczyk, 2015). Magnesium concentration is generally less than calcium (Venkatasubramani, and Meenambal, 2007). Magnesium is commonly regarded as the principal cations usually found in leachate. During the present study, Mg ranged from 21.83 to 60.35 (mg/Kg). Among seasons the maximum mean Mg concentration was recorded during summer season (43.90), which may be ascribed to escalate in temperature which increases the solubility of magnesium salts and hence, hardness of water is increased (Garg, 2003). However minimum was recorded during winter (32.28). Among sites maximum concentration of Mg was recorded at leachate outflow site (54.92), followed by 900m downstream (38.19), 1500m downstream (31.64) and least was recorded at 300m upstream (28.41) (Table 3). This decline in concentration of Mg with increase in distance from dumpsite may be due to dilution.
In municipal solid waste dumpsite leachate, heavy metals are usually present in trace amounts (Christensen et al., 2001). During early stages, there is generation of organic acids resulting in reduction of pH, thereby enhancing solubility of metals and ultimately concentration of heavy metals in a landfill leachate is increased (Kulikowska and Klimiuk, 2008).
Zinc is a very communal pollutant in environment; its occurrence may impede the water ecological environment. Human induced actions including municipal wastewater releases, coal burning power plants; industrial methods entailing metals; and atmospheric outcome are the main cause of Zn pollution [Pertsemli and Voutsa, 2014]. Ferocious release of zinc pollutes the surface, subsurface water courses and promotes groundwater contamination. The effects of high level consumption of zinc in humans causes lassitude, vertigo, appalling, inconvenience in writing efficiently, stress, dejection, drowsiness and hauling [Nriagu, 2007]. Concentration of zinc escalates in urine or blood of people as well as soft muscle of animals after utilizing polluted water through drinking, respiring or epidermis. During the present investigation, the mean concentration of Zn varied from 0.33 to 0.98 (mg/l) shown in (Table 4). Among seasons the minimum mean zinc concentration in water was noted during summer season (0.41), which may be ascribed to the photosynthetic assimilation or absorption by macrophytes during their growing periods and maximum during winter (0.63) may be due to the absence of macrophytes (Showqi et al., 2018). Among sites, maximum mean Zn concentration was recorded at leachate outflow site (0.79) and it showed decreasing trend with increase in distance from leachate outflow site. This decrease in concentration with increase in distance may be attributed to dilution of leachate.
Iron occupies fourth position in the order of plethora in the earth’s crust making up to 5.6%. The sources of Iron pollution in water can be geogenic or through industrial and municipal waste. Water carrying Iron seems jet black following reaction with tea and coffee (Colter and Mahler, 2006). It is crucial component of hemoglobin, myoglobin and a variety of enzymes and its dearth results in bloodlessness and loss of welfare. but, its excess concentration results in serious health issues in human beings like liver cancer, diabetes, cirrhosis of liver, heart disorders and importance etc. Its high concentration also alters colour, taste, odour of water, staining clothes and erodes water pipe lines (Behera et al., 2012).The affluence of Iron carrying refuses like cutlery and surgical equipments, trimming equipments, metal container, kitchen refuse etc give rise to increment in Fe accumulation in leachate from municipal solid waste (Jahan et al., 2016). The mean concentration of Fe in water span from 0.67 to 2.25 (mg/l) as shown in (Table 4). Among seasons the mean maximum Fe concentration was recorded during summer (1.39). This may be attributed to increase in temperature of water which results in the decrease in amount of dissolved oxygen. The decrease in oxygen concentration of water leads to slow oxidation of soluble Fe (II) to insoluble Fe (III) compounds, hence the amount of soluble iron increases during summer season. However minimum concentration of Fe was recorded during winter (0.88). Among sites, maximum Fe concentration recorded at leachate outflow site (1.77) may be because of presence of highly concentrated leachate, and minimum was recorded at 300m upstream. It decreases with increase in distance from leachate outflow site.
Copper is paramount element at optimum levels and becomes toxic at higher concentrations. The harmful consequences subject to higher concentration of copper are triggered to liver and also induce hepato-biliary evidences like midriff pain, cramps, nausea, diarrhea, and vomiting (Asokan et al. 2021; Gotteland et al. 2001). It has been reported that consumption of high amount of copper through quaffing water has eventuated in liver toxicity, mostly in newborn and adolescents. (Abedi Sarvestani and Aghasi 2019; Gomaa et al. 2021; Taylor et al. 2020). Nausea is affiliated with utilization of water carrying great concentration of copper. Copper is mostly found in abundance in bones and muscles owing to its size. Over loading of copper mutilates DNA, impedes enlargement of size and oxidative strain. (Asokan et al. 2021). In the current investigation the mean concentration of Cu (mg/l) ranged from 0.25 to 0.84(mg/l). Among seasons the maximum Cu concentration was recorded during summer season (0.51), which may be because of intrication of Cu and liquefied organic matter (DOM) in leachates, as Cu complexes has higher stability constants with organic matter which results in decreases the bioavailability and uptake by aquatic organisms (Kramer et al., 2005; Esakku et al., 2005; Olsson et al., 2007). While as minimum was recorded during winter season (0.33). Among sites maximum Cu concentration recorded at leachate outflow site (0.66) may be because of high concentration of Cu in leachate (Table 4). It decreases with increase in distance from leachate outflow site which may be attributed to adsorption by sediments and the organic matter (Akinbile, 2012; Alslaibi et al., 2011; Sabahi et al., 2009; Suman et al., 2006).
Mn is indispensible for human health and works as co-factor in the operative places of different enzymes and is prerequisite for regular expansion, subsistence of nerve and exempt cell performance, modulation of blood sugar and vitamins. [Aschner et al., 2007; Guilarte 2010; Crossgrove and Zheng, 2004]. However, overexposure may be baneful to most of the organ structure and over various periods of life. It has been reported that increased concentration of Mn in quaffing water leads to remarkably great concentration of Mn in hairs of school-going children, which is significantly associated with improved exuberant conduct, hinder appercipient maturity and diminish mental capacity. [Khan et al., 2012, Bouchard et al., 2011]. In the present study Mn value sweeps from 0.30 to 1.03 (mg/l). Among seasons highest mean Mn concentration noted during summer season (0.63) may be because of lower levels of dissolved oxygen while as minimum during winter (0.40) may be because of higher levels of oxygen in water, as dissolved oxygen is inversely related with Mn concentration in water (Kousa et al., 2020). Among sites maximum concentration recorded at leachate outflow site (0.80) may be because of high concentration of leachate and decreases with increase in distance from leachate outflow site (Table 5)
Future prospects and Recommendations:
It is evident from the current study that landfills have tangible impact on water quality which is modulated via leachates, so it is clear if the present situation at this site remains constant the effect of leachates on water quality will be more prominent and will affect human lives. The possible strategies that we can employ on landfills are illustrated in Flow chart. Human population is increasing at exponential rate which will also correspond to waste generation, hence diverse waste management strategies which are cost effective, sustainable and climate smart are imperative. The present landfill sites and their negative impacts on soil and water can be minimized by real time contaminant monitoring and execution of appropriate treatment strategies. Present study highlighted the pace at which landfills are and will be contaminating soil and water bodies. Which will aware policy makers for appropriate policies.