85% of tested water sources in Nigeria exceed safety limit — Study

A study has revealed that 85% of water sources tested in Nigeria exceed the World Health Organisation's arsenic safety limit. The research, published in the Journal of Applied Sciences and Environmental Management on September 21, 2026, highlights gaps in water quality monitoring, with over a third of states and the Federal Capital Territory lacking published data on arsenic contamination.

The study analyzed 945 water samples from 40 studies across Nigeria, with the highest concentration found at 4.645 milligrams per litre in Ebonyi State boreholes, 465 times the WHO limit of 0.01 milligrams per litre. Elevated arsenic levels were also reported in Abia, Anambra, Kano, and Nasarawa states. The researchers cautioned that their findings do not fully represent the national situation due to the limited scope of existing studies, some of which were conducted in areas already suspected of pollution.

The study's lead author, Excel Obumneme Amaefule, noted the difficulty in determining the extent of contamination without water quality data linked to health records. Experts emphasized the potential health implications of arsenic exposure, including skin abnormalities, increased risks of cancer, cardiovascular diseases, and diabetes.

The researchers urged for expanded testing in states without published data, mandatory water quality assessments for mining and industrial approvals, and a national surveillance system linking environmental measurements with health records.