Assessment of Heavy Metal Contamination and Associated Human Health Risk in Central Ganga Plain, India

Abstract

This study investigates groundwater quality in Raebareli district, India, with a specific focus on heavy metal contamination and its implications for human health and ecological risk. The district, part of the central Indo-Gangetic alluvium, is representative of regions facing significant groundwater pollution challenges. Using indices such as the heavy metal pollution index (HPI) and the ecological risk index (ERI), contamination levels were assessed through weighted arithmetic methods and sub-index calculations. The study identified lead (Pb) as the predominant contaminant, affecting 93.75% of analyzed water samples, with 59.3% of sites classified as critically polluted and unsuitable for drinking or other purposes. Health risk assessments revealed that cadmium (Cd) posed the highest noncarcinogenic and carcinogenic risks among the detected metals. Hazard quotient analysis indicated that children were more vulnerable to noncarcinogenic chronic health risks, particularly from Pb ingestion, which exceeded safe thresholds at 20 stations for adults and 22 stations for children. Cd contributed to 78.2% of carcinogenic risks in children and 75% in adults. Ecological risk assessments showed that 50% of the samples posed low ecological risks, 46.8% moderate risks, and 3.1% considerable risks. Statistical tools, including Pearson's correlation, hierarchical cluster analysis (HCA), and principal component analysis (PCA), revealed significant associations between metal pairs, distinct clustering patterns, and contamination sources, both natural and anthropogenic. The findings emphasize the urgent need for public awareness programs and rapid mitigation measures to safeguard groundwater resources and public health. Prolonged exposure to the detected heavy metals is linked to severe health conditions, such as neurological disorders, kidney damage, cardiovascular issues, and cancer, highlighting the critical need for sustainable water resource management. This study provides essential baseline data and insights to support informed decision-making and effective mitigation strategies for addressing heavy metal contamination in groundwater.