Health risks of arsenic and chromium in groundwater and surface water in India: A systematic review.

Background and objectives India ranks third in global cancer incidence. Groundwater often carries undetectable contaminants such as arsenic, a highly toxic element, and chromium, a probable carcinogen. This systematic review aims to identify patterns of arsenic and chromium exposure in Indian population through groundwater and surface water, and the resulting health effects, including cancer and other non-communicable diseases. Methods A comprehensive search was conducted in PubMed, Embase, and Scopus for English-language studies from inception to January 8, 2025. Studies assessing health effects of arsenic or chromium in groundwater or surface were included. After screening the articles, data on key health risk indices: hazard quotient (HQ) and carcinogenic risk, were extracted and categorised by standard thresholds. Heat maps and violin plots were used to represent health risk levels across studies and regions. Joanna Briggs Institute (JBI) critical appraisal tool was used for quality assessment. Results A total of 1259 articles were identified, with 63 included studies. All reported studies presented a low risk of bias. Arsenic ingestion indicated non-carcinogenic risks in 49% of adult and 60% of child-focused studies. Chromium ingestion risks were lower, reported in 12% and 14% of adult and children-focused studies, respectively. Carcinogenic risk was higher for both metals, particularly through ingestion. Higher non-carcinogenic risk was reported from groundwater than surface water, especially via dermal exposure in children. Affected regions were Punjab, West Bengal, Haryana, Delhi, Uttarakhand, and Jammu and Kashmir. Interpretation and conclusions Groundwater arsenic contamination poses a major public health threat in India, while evidence on chromium ingestion risks are limited.