Groundwater fluoride contamination in Coimbatore district: a geochemical characterization, multivariate analysis, and human health risk perspective

P J Sajil Kumar

doi:10.1007/s12665-021-09521-w

Abstract

In this paper, fluoride geochemistry and health risk of groundwater in Coimbatore district is studied. The order of dominance of ions were HCO3 > Cl > SO4 > CO3 and Na > Ca > Mg > K. Alkaline groundwater and the dominance of HCO3 and Na is favourable for the fluoride enrichment. Around 46% of the samples, N–NE regions, have F− higher than permissible limit of 1.5 mg/L. Pink granites, charnockite and gneisses in lithology is the possible origin of F−. However, NO3 vs F plot shows positive trend in some samples, indicating anthropogenic inputs of F−. Correlation plots of F− was trending positive with pH, HCO3 and Na and but negative for Ca, indicating the control of these ions in F− mobility. This result is supported by undersaturation of fluorite and supersaturation of carbonates. Four significant principal components were derived, which have explained 87% of the total variation. PC1 has high factor loadings for EC, Ca, Mg Na, Cl, SO4, NO3 indicating both natural and anthropogenic influences. PC2, PC3 and PC4 have higher loading for pH and HCO3, K and HCO3 and F−, respectively, indicating geogenic factors in the F− enrichment. Human health risk assessment (HHRA) by ingestion and dermal pathways were calculated using Hazard Quotient HQ and Hazard Index (HI). 27% of males, 36% of females and 39% of the children have HI > 1, posing noncarcinogenic risks.

Highlights

Groundwater is one of the most widely used natural resources and it is serving a major portion of the world’s population for safe drinking water
It is clear from these values that the groundwater is mainly alkaline nature (WHO 2011)
Groundwater was alkaline in all samples, Na and HCO3 were the dominant anion and TDS values varied from 100 to 3544 mg/L, suggesting a significant impact from the anthropogenic activities

Summary

Introduction

Groundwater is one of the most widely used natural resources and it is serving a major portion of the world’s population for safe drinking water. Groundwater contamination is a global issue for human health and an important concern in water supply schemes (Sajil Kumar 2017). The consumption of contaminated groundwater may cause serious health effects on human beings and other organisms (Majolagbe et al 2016). Groundwater contamination occurs due to both natural and manmade activities (Sajil Kumar et al 2014; Gu et al 2017). 74‐100, 12249 Berlin, Germany tanks for chemicals and oils etc., hazardous wastes, landfills, saline intrusion in coastal areas, atmospheric depositions, and rock–water interactions, among the types of contamination that occur due to natural enrichment, fluoride is one of the major factors. We focus on the enrichment of fluoride in groundwater and its adverse effects on human beings

Methods

Results

Conclusion