Mutagenicity and amount of chloroform after chlorination of bank filtered lake water

Chlorinated drinking waters produced from humus-rich waters often have a high content of halogenated organic by-products which increases the mutagenicity of drinking water. With in vitro chlorination experiments we studied the formation of chloroform (CHCl3) and mutagenicity of artificially recharged ground water samples. The water samples where obtained from an artificial ground water plant which infiltrates humus-rich lake water through an esker island. The chlorination experiments showed that bank filtration reduced strongly the formation of chloroform and mutagenicity of chlorinated water. Reduction in the amount of chloroform and mutagenicity in chlorinated waters was strongly associated with the decrease in the total content of organic carbon and with the decrease in molecular weight of organic matter during bank filtration.