Toxicity of Algae in Water of Chaohu Lake and Its Influence on Drinking Water Quality / 环境与健康杂志

ABSTRACT

Objective To explore the toxicity of algae in water of Chaohu Lake and its influence on the quality of drinking water.Methods In1999,the water samples were collected from the sampling location of A point as a discarded water source for Chaohu Water Plant 1.5km far from the lakeside of Chaohu Lake and the sampling location of B point as a water source in use for Chaohu Water Plant 3.0km far from the lakeside of Chaohu Lake.The species and count of algae in these water samples were analyzed.The determination of micro cystin,sanitary indexes of water quality,Ames test,micronucleus test and SCGE test were carried out in the water samples from B point and the finished water from water plants using water source for B point.Re -sults83species of algae belong to8phylum and49genus were found in water samples from A point and B point in Chao hu Lake.The anual averages of algae count in water sample of B point (8205.67?10 4 /L)exceeded16.8%of that of A point water samples(7024.27?10 4 /L).Microcystin was found in12water samples among total16water samples collected from the lake water,two of which revealed excessive content s of microcystin exceeding standard,but it was not found in raw water and finished water samples from five plants in Hefei and Chaohu Lake[except the4th water plant (4th WP )].After transportation and stor-age,the raw water of4th WP of Hefei with lower content s of microcystin revealed higher contents of microcystin exceeding the standard in primary finished water samples of clean-well finished water storage,but it couldnt be found in secondary finished water samples with the processes of coagulation,ch lorination and active carbon-filtration.The total nitrogen and other6indexes of raw water of4th WP exceeded the related standards ruled by GB3838-2002Surface Water Environment Standard Grade V in different degree,but above6water quality indexes could reach the related sanitary standard after water treatment.Ames test and micronucleus test indicated that the raw water of4th WP presented suspectable mutagenicities which couldnt be removed by co-agulation and chlorination.SCEG test also showed that the organic extracts of the raw water of4th WP presented DNA damage effects.Con clusion The water source in use in Chaohu Lake revealed heavier pollution by algae compared with the original discarded water source in Chaohu Lake.Chaohu Lake water and its finished water revealed higher levels of microcystin exceed-ing the standard and the organic extracts from raw water and finished water presented suspectable mutagenicity.