Appraisal of shallow groundwater quality with human health risk assessment in different seasons in rural areas of the Guanzhong Plain (China)

The COVID-19 lockdown has been reported as a "ventilator" for the reinstatement of natural resources across the globe. Hence, the present study attempts to evaluate the impact of COVID-19 lockdown on the water quality of River Gomti across its stretch of ~960 km through the assessment of 'Water Quality Index' (WQI). The study also highlights the potential risk of faecal-oral transmission of COVID-19 through intake of river water facing the issue of direct discharge of domestic sewage. A deterioration in the water quality was witnessed at ~69% sampling locations during the lockdown period (May 2020). Interestingly, none of the water samples during the pre-lockdown, lockdown, and post-lockdown periods across the whole stretch belonged to the "excellent" category (WQI<25). The DO levels fell across ~69% and ~88% of the sites during the lockdown and post-lockdown periods, respectively. Moreover, there was an increase in the BOD5 levels across ~69% and 75% of the sites during lockdown and post-lockdown periods, respectively. These findings indicate that the release of sewage without or with partial treatment is a chief contributor of water pollution in the groundwater fed River Gomti. Thereby, highlighting the possible risk of faecal-oral transmission of the corona virus, and creating a major concern for the residents across its stretch. The urban sprawl and riverfront development in Lucknow city also emerge as potential causes of water quality deterioration in River Gomti, considering that the water quality at five sites within the city was under the "unfit" category regardless of the lockdown situation. Thus, the urgent need of management of domestic sewage release into the river and further research on the potential risk of faecal-oral transmission of COVID-19 have been suggested in the study.

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Effect of COVID-19 lockdown on the water quality index of River Gomti, India, with potential hazard of faecal-oral transmission.

In this paper, the spatial distribution of fluoride (F‒) and manganese (Mn) in groundwater was described and the overall groundwater quality was assessed with the entropy weight water quality index (EWQI) in Weining Plain, northwest China. The probabilistic health risk of F‒ and Mn in groundwater was assessed by the Monte Carlo stochastic simulation method. The results show that 50 groundwater samples (a total of 144) belong to poor and very poor quality because of agricultural activities, industrial development, and the local hydrogeological conditions. Groundwater quality in the upper reaches of the Yellow River is better than that in the lower reaches. The average health risks faced by children and adults are 4.59 and 0.62, respectively. If the uncertainty of the model parameters are considered, the mean risks faced by children and adults are 6.84 and 0.92, respectively, indicating that the health risk to residents, especially children, cannot be ignored. Compared with dermal contact, drinking water intake is the main exposure way to harm residents’ health. F‒ contributed higher to the health risk than Mn, and children face greater risk than adults. Stochastic simulation can reflect health risks more comprehensively than the deterministic methods. The study results are helpful for decision makers to take measures for the safe supply of drinking water in the study area.

Occurrence and Distribution of Groundwater Fluoride and Manganese in the Weining Plain (China) and Their Probabilistic Health Risk Quantification

Recently, high levels of Cr6+ in groundwater have been found and are threatening public health in the Guanzhong Basin of China. For this reason, this study aims to specify the occurrence and spatial distribution of groundwater Cr6+ and to analyze the favorable hydrogeochemical environment elevating its concentration in the Guanzhong Basin. The impacts of Cr6+ on human health were also estimated based on the health risk assessment model recommended by the USEPA. Results show that 45.40% and 37.36% of the groundwater samples contain Cr6+ concentration lower than 10 μg/L and ranging within 11–50 μg/L, respectively. And they are predominantly of HCO3-Ca and HCO3-Ca(Mg) water type. About 17.24% of the total water samples present Cr6+ concentrations exceeding the acceptable limit for drinking purpose of 50 µg/L, and are mainly classified as HCO3-Na water type. Low Cr6+ groundwater is mainly observed in the alluvial aquifer. Cr6+ concentration in the samples from the loess aquifer is higher due to low groundwater velocity caused by the low permeability of loess, as verified by the relationship between Cr6+ and major ions. The relationship between Cr6+ and pH and molar ratio of Na+/(Na+ + Ca2+) suggest that alkaline environment and cation exchange are beneficial to high concentration of Cr6+ in groundwater. Industrial activities are also responsible for the elevation of Cr6+ to some extent. Health risk assessment results show that the adults and children in the study area face higher carcinogenic risks than non-carcinogenic risk induced by Cr6+.

Occurrence, Controlling Factors and Health Risks of Cr6+ in Groundwater in the Guanzhong Basin of China

The sustainable growth of any society is in direct proportion with developing novel methods and technologies for the management of its environmental quality. The use of Magnetic Nanoparticles (MNPs) has emerged as an efficient tool for remediation of wastewater owing to its intrinsic qualities including size, surface effect, quantum effect, etc. These intrinsic properties of MNPs have diversified their application in managing the qualitative stress on water resources. The present review aims to assess the use of MNPs in removing organic and inorganic contaminants from wastewater. Insights into various synthesis methods and their effects on contaminant removal are also presented. It is reported that MNPs provide target specificity and cost-effectiveness as compared to conventional treatment methods. Moreover, the biological synthesis of MNPs is proven to be eco-friendly and aids in sustainable development. Nearly 100% removal of various types of contaminants such as pharmaceuticals and personal care products, dyes, pesticides, heavy metals, etc. can be achieved through MNPs. Some MNPs have shown a magnetic saturation reaching up to 70 emu/g, and recycling up to 5 cycles with >95% removal efficiency. High pollutant removal efficiency (>98%) can also be achieved in a short time (within 5 min) by MNPs. It is noteworthy that, nanosorption along with the redox reactions are the most frequently used and efficient mechanisms of contaminant removal from wastewater samples.

Synthesis and characterization of magnetic nanoparticles, and their applications in wastewater treatment: A review

The aim of the present study was to assess the status of heavy metal contamination and health risks associated with the use of water from River Gomti by millions of people. The value of the degree of contamination (Cd) was found to be ‘11.93’, signifying ‘high’ risk levels due to heavy metal contamination in River Gomti across an approximate stretch of 61 km including upstream, midstream, and downstream locations of Lucknow city. The potential sources of heavy metal pollution in River Gomti include both sewage and industrial effluents, being transported by drains which overflow into the river. The heavy metals were found to have low mobility owing to the ‘near neutral’ pH of river water. The findings from the human health risk assessment revealed that the hazard index associated with non-carcinogenic risks exceeded the permissible limits at all sampling stations. The highest health risk was found at Bharwara sewage treatment plant discharge point, downstream of Lucknow city signifying the elevated levels of heavy metal in the river water post treatment from Bharwara STP. The results of carcinogenic risk assessment suggested that children were more susceptible to health risks, and immediate remedial measures are required to control the elevated levels of heavy metals at all the sampling stations.

Environmental contamination by heavy metals and associated human health risk assessment: a case study of surface water in Gomti River Basin, India

The aim of the current study was to evaluate the status of heavy metal contamination in River Gomti for Lucknow district. The quantification of the pollution levels in River Gomti over a stretch of ~ 61 km, has been attempted through heavy metal pollution index (HPI). The results suggested that 30% of the total sites fall under the category of ‘highly polluted’ (HPI > 30), and 60% of the sites are designated under ‘critically polluted’ category (HPI > 100). Further, it was found that the mean HPI value across the stretch of the study area was 149.29 signifying towards the category of ‘critical pollution’ (HPI > 100). The principal component analysis results suggest strong positive loadings on arsenic (As) and lead (Pb) similar to the hierarchal cluster analysis (HCA) results which signified towards close association between As and Pb. A ‘good’ correlation (0.51 < r < 0.89) has been found for As with Pb and Mn. The possibility of anthropogenic intrusion as a cause for heavy metal contamination at all sites is also signified through the results from HCA. Thus, the untreated discharge from the agricultural runoff, sewage system including domestic and industrial wastewater has emerged as a potential cause of heavy metal contamination in the river water.

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Evaluation of heavy metal pollution for River Gomti, in parts of Ganga Alluvial Plain, India

In the current study, attempts were made to analyze the effect of COVID-19 lockdown on the heavy metal concentrations in River Gomti through comparison with pre-COVID-19 lockdown status. The concentration of all the six heavy metals (As, Cd, Cr, Fe, Mn, and Pb) clearly shows a significant reduction, highlighting the impact of closure of agricultural, industrial, and commercial activities. The values of heavy metal pollution index (HPI) at all sites have also decreased with the maximum improvement at Site S1 (Chandrika Devi), signifying the impact of reduced agricultural runoff into the river from nearby fields. The correlation analysis stated a strong correlation between HPI and Cd, signifying the relatively high weightage of Cd in pollution levels. Findings from the Caboi diagram suggest classification of all water samples under the ?near neutral-low metal? category.

Ramsha Khan

Papers

Effect of COVID-19 lockdown on the water quality index of River Gomti, India, with potential hazard of faecal-oral transmission.

Synthesis and characterization of magnetic nanoparticles, and their applications in wastewater treatment: A review

Environmental contamination by heavy metals and associated human health risk assessment: a case study of surface water in Gomti River Basin, India

Evaluation of heavy metal pollution for River Gomti, in parts of Ganga Alluvial Plain, India

Assessment of the impact of COVID-19 lockdown on the heavy metal pollution in the River Gomti, Lucknow city, Uttar Pradesh, India