Purpose: To explore the mutagenicity of organic extracts of tap water in a certain city in mice. Methods: Each 200 L of water was collected separately from Huai river source water, water of clarifying filtration, chlorinated tap water and reservoir's water. After being adsorbed and concentrated, water samples were poured into mouse stomaches. Micronucleus frequency in mouse thoracic bone-marrow polychromatic erythrocyte (PCE) and sperm deformity rate were determined. Results: Mutagenicity of some degree wer...