Nitrate contamination in groundwater and its evaluation of non-carcinogenic health hazards from Arjunanadi River basin, south India

Abstract

Nitrate (NO3-) contamination of groundwater is increasingly getting common in many places across India. Here, we present new data about nitrate pollution and the associated health consequences for infant, children, and adult population by evaluating 94 groundwater samples from the Madurai and Virudhunagar regions within the Arjunanadi River basin, situated at the southern region of India. Nitrate (9–221 mg/L) remained surpassed the WHO's recommended limit (>45 mg/L) in 34% samples. The piper diagram results specified that 75% of the samples fall in Mixed CaMgCl type. The correlation of nitrate results showed that groundwater of the region degraded by agricultural and industrial activities. The Nitrate Pollution Index (NPI) results of samples revealed significant pollution class, n = 18 (19%) and very significant pollution class, n = 26 (28%) in the study region. Its spatial distribution covered an area of 456.3 km2 in the risk zone with more than permissible nitrate. Among the shallow aquifers, about 16% of whole samples were in the high risk and 9% in very high-risk. Similarly, about 6% samples from deep aquifers were also in the category of high risk. The Water Quality Index (WQI) of groundwater samples indicateed 39% as good, 48% as poor and 9% as very poor to unsuitable. The health risk assessment from intake (HQintake) and skin contact (HQdermal) suggested 64%, 45% and 32% of samples with THI >1 pose hazard for infant, children, and adult population, respectively. The health risks and assessing groundwater quality indicated the necessity of regular groundwater quality monitoring for better long-term health management in this region.