Heavy metal contamination assessment and its associated human health risk evaluation in the Mahanadi River sediments, India

The deltaic areas of the Mahanadi River basin are densely populated and are prone to contamination due to sewage, industrial waste, and agricultural runoff. The present study offered a systematic approach to evaluate the degree of heavy metal pollution in sediment and its impact on human health. The granulometric study revealed a relatively violent energy condition in the study region. Statistical parameters such as cluster dendrogram analysis and principal component analysis revealed a mixed source at Kujang and the dominance of a mafic source at Subala. The mean concentration of Co (47.25 ppm) and Pb (44.70 ppm) at Kujang and Co (37.03 ppm) and Pb (61.27 ppm) at Subala exceeded the global average value. The geo-accumulation index suggested Co and Pb contamination (each varying from 1 to 2) in the study region. The enrichment factor (EF) showed a moderate to significant enrichment of Co (EF = 8.5) at Kujang and a moderate enrichment of Co (EF = 2.2), Pb (EF = 3.6) and Zn (EF = 2.3) at Subala, indicating anthropogenic pollution, possibly from agriculture land due to heavy use of pesticides in the investigated region. The exposure pathway for both non-carcinogenic and carcinogenic risk was via oral ingestion. The human health risk suggested no significant non-carcinogenic risk for adults and children in the study region. However, the carcinogenic risk in children due to Cr posed a mild threat. Therefore, each day’s intake of these chronic metals must be examined as their collective effect could result in various health complications for children and adults.