Mutagenicity of water and sediment extracts from the Yongdinghe Watershed

Potential mutagenicities of water and sediment in Guanting Reservoir/Yongdinghe River Watershed in Beijing, China were assessed using the Ame's tests for the organic pollutants. For different sampling sites, the results were indicative for the existence of mutagens. Furthermore, by using different types of Ames tests, different types of mutagens in water and in sediment were elucidated. The results on Ames tests for water concentrates and sediment extracts could be obviously differentiated. Mutagens in water were mainly direct-acting mutagens whereas in sediment they were mainly pro-mutagens, which exhibit mutagenic effects only after metabolic activation. In general, among all the six sampling sites, site-1, site-2 and site-4 were potentially at mutagenic risk. In a trial to find the causes of mutagenicities in the sediment samples, chemical analysis was performed for polychlorinated biphenyls (PCBs) and organochlorinated pesticides. However, the available data were not sufficient to explain the mutagenicity in the sediment. Integration of the results of Ames test and chemical analysis on overlying water and sediment samples in Guanting Reservoir and Yongdinghe River indicated that this catchment was moderately contaminated by PCBs and organochlorinated pesticides thereby causing a significant mutaginicity in water and sediment. Special attention should be given to the water quality in site-1 and sediment quality in site-4.