Chromium in Water and Carcinogenic Human Health Risk

Understanding the extent of human health risks with an emphasis on carcinogenesis development attributable to potentially toxic chemicals is critical to effective prevention and mitigation strategies. Chromium (Cr), mainly the hexavalent chromium (Cr (VI)), is a chemical associated with cancer when found in drinking water, making it a major public health issue. This study assessed a possible carcinogenic human health risk among the general population due to exposure to total or hexavalent chromium. We performed a systematic review of the international scientific literature, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol to determine the human risk of cancer mortality and morbidity. In total, 76 articles were checked for eligibility, 13 of which were included in the final systematic review. Only scientific articles from January 2000 to November 2022 published on PubMed were included. Data from both epidemiological ecological studies (Relative Risk and Rate Ratio-RR and Standardized Mortality Rate-SMR) and epidemiological case studies (Lifetime Cancer Risk-LCR, Incremental Lifetime Cancer Risk-ILCR, Cancer Risk-CR, Hazard Quotient-HQ, Hazard Index-HI, Health Risk Assessment-HRA, Disability-Adjusted Life Year-DALY, and Chronic Daily Intake Index-CDI) were included for the overall assessment of carcinogenicity in the general population. According to most articles, there is credible evidence that hexavalent chromium via water is indicated as a major contributor to the global burden of cancer in humans. Some of them emphasize malignant neoplasms in the lung, liver, stomach, and genitourinary system. Although the health index data of the case studies are based on a limited number of samples, they raise concerns about the possibility of an increase in the degree of carcinogenesis. However, there are significant limitations due to the lack of information on the dose and duration of exposure in the target group. Further research involving extensive analysis of the association of the two variables is needed, which depends on more complete information extraction and advanced methodologies.