ASSESSMENT OF MICRO-POLLUTANTS IN WATER RESOURCES OF WESTERN UTTAR PRADESH, INDIA AND THEIR REMOVAL BY PHYTOFILTRATION

Abstract

Micro Pollutants (MPs) such as Heavy Metals (HMs) and Emerging Contaminants (ECs) are gaining serious attention nationally as well as globally among the research communities due to their toxicity and a potential threat to humankind. Groundwater (GW) is one of the most precious gifts of nature to sustain life on earth. Geogenic and anthropogenic activities are being played a significant role in its contamination and quality degradation. MPs have the tendency to bioaccumulation and resist to biodegradation, which causes noxious effects to the population, even a low level of concentration. The present study was taken up to investigate the MPs concentrations in groundwater of rural areas of Saharanpur and Shamli district with more emphasis on rivers catchment. The whole analyzed results were compared with BIS-2012 and WHO-2011 standards for drinking water (DW). The study was extended for evaluation of three rivers water quality, namely, Hindon, Dhamola and Krishni. Physiochemical parameters were also analyzed in both ground and surface water of the study. In the first phase, eight HMs were analyzed in 20 villages of Saharanpur rural. Fe and Hg were exceeded the permissible limit at all sampling locations and in the case of pesticides, OCPs, β-HCH and Lindane, while OPPs, Parathion were detected above the safe limit of DW. In the second phase of work, Saharanpur rural and urban, including both rivers Hindon and Dhamola, were evaluated for HMs contamination. Ten HMs such, As, Cr, Cd, Cu, Fe, Hg, Mn, Ni, Pb and Se were detected in both GW and SW, including physiochemical parameters, i.e., pH, EC, TDS, chloride, fluoride, nitrate, sulphate, phosphate and turbidity. The concentrations of Fe, Hg and Se were found above the permissible limit in both GW and SW at all sampling points. Further study was extended to another district of western Uttar Pradesh, namely Shamli. MPs (HMs and ECs) were investigated in groundwater and surface water of Krishni River. Ten HMs and approximately a wide number of pesticides (22) were evaluated in both GW and SW samples. Fe, Hg and Se among all chosen HMs were exceeded the safe limit at all sampling locations. α HCH, Aldrin and Dieldrin were detected above the permissible limit in GW samples of Shamli. The findings of three rivers have been used to compute four indices in SW, namely heavy metal pollution index (HEI), degree of contamination (Cd), Nemerow index (NI) and comprehensive pollution index (CPI). These indices are effective methods of rating and endorse the water quality with special reference to HMs. The critical values of all indices such HEI, Cd, NI and CPI are ≥15, ≥3, ≥3 and ≥2, respectively. The results of all indices exhibited the very poor quality of all rivers. However, Hindon River has more pollution load than the other two rivers. For easy visualization and prediction of contaminated sites, GIS mapping was incorporated in the present study. Tools, Arc-GIS v10.2.1 and surfer v8.0 were used for the preparation of distribution maps. All GW and SW sampling sites of the study area were taken up for mapping and the interpolation IDW method with contour lines was used to draw maps. This method gives a clear image of contaminated sites on the basis of individual pollutant concentrations in comparison to another one. Mapping also revealed about the hot-spot zones scenario in terms of pollution. Furthermore, study was extended to human health risk assessment (HRA) as suggested by USEPA model due to micro pollutants (HMs and pesticides) exposure in drinking water via ingestion and dermal absorption pathways to adults and children. Non-carcinogenic (NCR) and carcinogenic risks (CR) assessments were assessed on the basis of individual body weight (BW), concentration of chemicals (C), water ingestion rate (IR), exposure frequency (EF), exposure duration (ED), average time (AT) reference dose through ingestion and dermal routes (RfD), oral slope factors and many more required parameters. NCR was calculated as individual Hazard Quotient (HQs) and cumulative Hazard Index (HI) values of chosen pollutants. CR values have been computed on the basis of the cancer slope factor. HRA was calculated for HMs and pesticides, both separately in this study. The findings of HRA due to HMs exposure to the local population showed NCR and CR risks. HIing was far greater than unity at most of the sampling locations, which indicated potential health risks to local residents. It was estimated that HIing> HIderm for both adults and children. HItotal, sum of HIing and HIderm was higher for children. The magnitude was increased when both routes have been added simultaneously in this study. CR values as excess lifetime cancer risk (ELCR) were assessed of As, Cr and Pb among all HMs due to availability of oral slope factor. ELCRing and ELCRderm were higher of As than Cr and Pb for both adults and children. It was observed that ELCRing>ELCRderm for both sub group of population. ELCRtotal, the sum of ELCRing and ELCRderm was found above the acceptable range (10-4 ̶ 10-6) at all monitored stations of the present study, which evoked serious health risks to local residents. The value of ELCRtotal (children)> ELCRtotal (adults) signified that children are more prone to health risks it may due to their lower age and exposure duration (ED). HRA due to pesticides at the Saharanpur region was assessed. HQ and HI of Lindane were greater than unity, which means health hazards to the local population. CR values were found above the acceptable range for all chosen pesticides, which evoked potential health risks to local residents. HRA for Shamli due to broad exposure of pesticides was evaluated via single-mode exposure, i.e., oral route. HQs and HI (NCR) found below unity means no health risk to people. CR values as total lifetime cancer risk (TLCR) showed significant health risks to local habitants as values observed beyond the acceptable range. Finally, in the present study, a novel removal method was employed for the removal of MPs from wastewater. Phytofiltration was demonstrated to remove contaminants. Two plant species, namely water hyacinth and water lettuce, were chosen in the constructed wetland (CW). The field-scale study was performed in the Shamli region. The removal potential efficiency was evaluated by both the plants. Considerable reductions in concentrations of HMs and ECs have been observed. The highest decline was observed in HMs, i.e., Mn (approx. 96%), followed by Pb and other metals. Moreover, chlorpyrifos reduction was approx 79%, followed by Malathion. The whole findings not only show that GW of the present study is unacceptable for drinking but also a soft indication of the influence of urban, industrial process, and agricultural practices on the GW quality. Prompt actuation of water resources protection laws is mandatory to curb incessant pollution of the monitored area.