Objective To know the quality change trend of outgoing water from the water plants in the rural areas in Dongguan, Shunde and Zhongshan of Guangdong. Methods The quality reports of the outgoing water and the supply capacity of the water plants in 1999-2003 were analyzed. Results The up to standard rate of outgoing water showed an increase in the three areas in 1999-2003, from 98.00% to 98.55%, 95.13% to 99.43% and 97.95 to 99.63% respectively, but the bacteriological indexes were still noteworthy. Conclusion The outgoing quality of water plants in Dongguan,Shunde and Zhongshan of Guangdong is satisfactory, the up to standard rate of outgoing water from the larger scale plants is higher compared with the smaller ones.

Objective To know the quality of drinking water produced by deep treatment systems in Guangdong Province.Methods The unified investigation form was used,the water supply systems were selected from 4 cities,Guangzhou,Shenzhen,Zhuhai,Dongguan.pH value,conductivity,ozone,COD,TOC,heavy metals,bacteria were determined in 2004.Results Having investigated 169 systems,reverse osmosis,nanofiltration and ultrafiltration equipment used to treat water accounted for 74.40%,19.05% and 6.55 % respectively.The use of ozone disinfection was 70.7%.45.8% of the systems,the water cycled twice per day,and 29%,no water quality test was conducted according to the regulation.The quality of water with deep treatment was satisfactory compared with the common tap water.Conclusion The quality of water produced by deep treatment systems is considered better than the common tap water and the applicable water treatment units should be selected,the routine water quality test and management should be conducted.

ve To explore the methods for sanitary safety test of water purifier. Methods The water purifiers using active carbon, KDF and molecular sieve as absorptive materials and hollow fibers as filter materials were collected for sanitary safety test. The water purifiers were irrigated by pure water continuously for 15, 30, 45 and 60 min respectively first, and then were immersed continuously for 24 h by pure water, the variations of turbid-ity, pH value, total dissolved solid and chemical oxygen demand (COD), etc, of the immersing water were observed. The water purifiers were also irrigated continuously for 1 h at first, and then were immersed continuously for 5, 15, 24, 48, 72 h and 1 week by pure water respectively, in the end, the variations of those 4 sanitary indexes mentioned above were also detected. Results Significant differences were observed in those 4 indexes between the immering water samples obtained after 15 min-irrigation and 30 min-irrigation, 30 min-irrigation and 45 min-irrigation (P

Objective To explore the effects of ingestion of purified drinking water from water treatment devices on health of rats. Methods Under the same feeding conditions, the Wistar rats were divided into different exposure groups exposed to different kinds of drinking water such as electrolytic ion water (alkaline water), reverse osmosis water, middle hollow fabric filtered water, copper-zinc ally (KDF) filtered water, municipal water and source water respectively. The changes of the indexes including organ coefficient, routine blood test, blood biochemistry and electrolyte were observed at the 3rd and the 6th month of the exposure. Results Higher levels of the count of white blood cells and neutrophil, and higher concentrations of seralbumin and total albumin in serum were observed in rats of tap water group compared with those in control group (P