Groundwater Geochemistry. Группа авторов

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0.4–5.6 ppm in the pre‐monsoon, 0.1–6.7 ppm in the post‐monsoon 10–190 ppm in premonsoon, 25–195 ppm in postmonsoon 55.2 ppm in pre and 62.9 ppm in postmonsoon Raju et al. (2012) Sonbhadra, Uttar Pradesh, India 0.3–11 ppm Raju (2017) Telangana State, India 0.99 51.53 ppm 117.87 ppm 119.27 ppm Rao et al. (2018) Andhra Pradesh, India 0.011 and 0.081 ppm 0.008–0.084 ppm 0.010–0.091 ppm Reddy et al. (2012) North district of Delhi, India 0.0003–0.1 ppm 0.05–7.14 ppm 25–1202 ppm 20–2000 ppm 11–4433 ppm Sarkar and Shekhar (2013) Vaishali and Bhagalpur District, Bihar, India 20 ppb in Vaishali and 143 ppb in Bhagalpur Singh et al. (2014) Bhalswa landfill, Delhi, India 0.01–1.90 ppm 0.64–6.34 ppm Srivastava and Ramanathan (2008) Ballia and Ghazipur, Uttar Pradesh, India 43.75–620.75 ppb Srivastava and Sharma (2013) Ranchi city, Jharkhand, India 0.0–200 ppb 0–2.19 ppm 0–268 ppm 18.2–303 ppm 2–200 ppm 0–140 ppb 0.0–4200 ppb Tirkey et al. (2017) Parichha, Jhansi, India 0.036–0.061 ppm 0.013–0.178 ppm 0.186–11.98 ppm Verma et al. (2016) Puri city, Odisha, India 0.01–2.04 ppm 7–320 ppm 3–11 222 ppm 0.04–3.5 ppm Vijay et al. (2011) Kadava River basin, Nashik, India 34–3516 ppb 0.013–0.142 ppm 0.092–3.558 ppm Wagh et al. (2018)

      1.7.2 Remediation

      Various techniques might be adopted to lessen the concentration of Se in drinking water. The commonly applied techniques are ion exchange, activated alumina (AA), reverse osmosis (RO), and distillation. Ion (anion) exchange can decrease selenium by 90–95%, as selenate ion is highly favoured. Though oxidation of Se (IV) is more problematic, it can be done easily with the help of free chlorine. Se (IV) can be transformed to Se (VI) within five minutes by maintaining the concentration of free chlorine to 2 mg/L. The pH between 6.5 and 8 is observed to be an ideal rate of oxidation. Removal rates for other methods used for selenium elimination are distillation (>98% removal), activated alumina (85–95% removal), and reverse osmosis (RO) (>90% removal) (CGWB 2014).

1.8 Conclusion

      India has different biogeographical regions including the Himalayan regions, desert, semiarid areas, Western Ghats, Deccan Plateau, Gangetic plain, northeast India, islands and coastal regions. Based on this study, it can be seen that most of the geographical areas of India are facing geogenic contamination in groundwater. Arsenic and fluoride contamination have been reported in bulk in the Gangetic Plain. Salinity problems are more concentrated in the coastal, arid, and semiarid regions, while heavy metal contamination has been observed more or less everywhere in India. There is a need for continuous monitoring of the groundwater parameters to check the concentration of the geogenic contaminant in the water system. The remediation method should be applied in the regions of the geogenic contaminants to cope with the present and future worst situations of health‐related problems.

References

      1 Achary, G.S. (2014a). Studies on ground water pollution due to iron content in Cuttack city, Odisha, India. International Journal of Current Engineering and Technology 2: 86–89.

      2 Achary,

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