Abstract:
Objective To analyze the present situation on drinking-water quality of centralized water supplies in rural areas of Lanzhou.
Methods A total of 471 rural centralized water supplies in the city were selected by random sampling. The finished water and terminal piped-water samples were collected and examined in dry season (from March to April) and rainy reason (July to August) of 2013 to 2015. Water samples were collected and examined in accordance with the Standard Examination Methods for Drinking Water (GB/T 5750-2006). The evaluation of water samples was carried out according to the Standards for Drinking Water Quality (GB/T 5749-2006). SPSS 18.0 software package was used to perform chi-square test.
Results The overall qualified rate of water samples was 47.7%. The qualified rate ground water (54.0%) was significantly higher than that of surface water (41.6%, P < 0.05). The water qualities between finished water and terminal piped-water and those between dry and rainy seasons were not significantly different. The qualified rates of 7 indicators, including total coliforms, heat reistant coliform, total numbers of colony, turbidity, sulfates, total dissolved solids and total hardness were less than 90%. In addition, the qualified rate of total coliform (74.7%) was the lowest in this study.
Conclusions The qualified rate of centralized water supplies in Lanzhou was low, and showed a downward fluctuation trend. The main reason caused the low qualified rates was microbial, chemical and acceptability indicators in drinking-water.