Objective To know the cause for contamination of drinking water in a hotel. Methods Samples were taken from the reservoir 1 h, 14 h, 22 h and 33 h after contamination and the perceptible character, chemical and bacteriological test were done by using the methods in Analytical Methods for Water and Sanitary Standard for Drinking Water Quality(2001). Results The turbidity increased at 14 h after contamination and the highest level reached 3.82 NTU. The residual chlorine in tap water from the reservoir was less than 0.05 mg/L, the total count of bacteria was 940 cfu/ml, the total coliform bacteria was more than 1 600 MPN/100 ml and fecal coliforms was 130 MPN/100 ml. Conclusion The contamination of drinking water in the investigated hotel is caused by drinking water reservoir leakage, so more attention must be paid to the contamination of drinking water reservoir.

Objective To provide scientific basis for prevention of source water pollution and minimization of impacts of biological pollution on drinking water quality.Methods The source water and finished water were determined based on the National Sanitary Method for Determination of Drinking Water(GB5750-1985),the sanitary quality of source water was classified based on the National Standard for Environmental Quality of Surface Water(GHZB1-1999),the sanitary quality of finished water was evaluated based on the National Sanitary Standard for Drinking Water(GB5749-1985).Results 36.8% of the accidents of source water pollution were induced by biological pollution,which mainly occured in rivers and lakes. Conclusion The important countermeasures for the minimization of source water biological pollution were to improve the process of water treatment and to develop the deep water treatment for conventional water treatment.

Objective To understand the proliferation of algae in Hanjiang River during low water period. Methods Identification and counting of algae was carried out in water samples collected from the locations with a depths of 0.5 m, 1.0 m and 1.5 m under the surface of water in the section of Zongguan water plant of Hanjiang River during low water period. Results The temperature of water of Hanjiang River was 19 ℃. The dominant algae was Bacillariophyta with a constetuent ratio of 72.38%, others were Chlorophyta (13.35%), Cryptophyta (9.68%), Cyanophyta (4.12%). The algal count was 1.8?10 4/L. Out countless diatom shells were found also. Conclusion The water pollution by algae of water of Hanjiang River during low water period should be paid more attention to, and its monitoring should be strengthened.