Mutagenic Potentials of Potable Water From Ground Sources

The presence of compounds with mutagenic activity in drinking water by means of short-term mutagenicity tests have been revealed in many studies. The influence of the different water treatment steps on the mutagenicity of some drinking water samples were evaluated using the Ames test.

Four different types of samples were collected from four water treatment factories within Port Harcourt metropolis: raw water from borehole (1), water after sand and granular activated carbon filtration (2), water after reverse osmosis (3), and water after Ozone and UV treatment (4). These samples were subjected to mutagenicity test using two mutant strains of Salmonella typhimurium (TA 100 and TA 98) without S9 activation enzyme.

The mutagenic analysis results revealed that raw water samples from Kent and Rivoli table water products showed mutagenic potential with TA100 and TA 98, respectively. But Kent table water showed more mutagenic potential than Rivoli and Fressi table water samples. Fressi table water is predominantly cytotoxic with all the treatment processes except for UV treatment with TA 98 strain. The finished products (water after ozone and UV treatment) of Kent table water and Rivoli table water also showed mutagenic potentials higher than those treated with TA100 and TA98 without S9 mix, respectively. Only the samples treated with activated carbon showed highly reduced mutagenic potential.

This study highlights the mutagenic effects of water treatment as another quality assessment option for assessing the portability of water samples. Water treatment with activated carbon can be reintroduced after disinfection with ozone/ultraviolet to eliminate possible mutagenic by-product in the finished product.