Assessing the Human Health Risks of Heavy Metal Contamination in Groundwaters: A Comparative, Multi-Regional Study

Abstract

Groundwater is an important source of drinking water in many rural and urban areas. This can include heavy metals from stone, industry, agriculture, mining, and plumbing. This paper compares human health hazards from arsenic, lead, cadmium, chromium, manganese, iron, and nickel in selected groundwater regions. The study used general data from Bangladesh, India, Pakistan, China and Nigeria. World Health Organization (WHO) guidelines and risk assessment methods are also used by the U.S. Environmental Protection Agency. No new field samples were taken. Therefore, this paper is a secondary data study and practical review. The results show that arsenic is the leading cause of cancer risk in South Asia. Bangladesh is facing significant exposure to arsenic in shallow wells. Pakistani studies show that arsenic levels are very high in some parts of Punjab. Under India's supervision, the national excise rates are low, but the affected areas are still prominent. China's data show that there is strong manganese and iron enrichment in the South Dongting Lake reservoir. Children had a higher risk index than adults. Nigerian data shows that there is a local abundance of lead, nickel and cadmium in Lagos' groundwater. Children are generally at higher risk because they drink more water per kilogram. The study recommends risk-based surveillance, treatment at home, safe exchange between wells, source control, and public reporting. It also supports periodic testing by ICP-MS or AAS where resources allow. The biggest limitation is that the datasets use different years and sample designs. However, this comparison shows clear public health priorities for groundwater conservation.