Discussion on Strategy for Water Quality Monitoring after Regional Water Supply in Taihu Region

Objectives To explore the strategy on water quality monitoring after the implementation of regional water supply in Taihu region. The surveillance data in 2008-2012 of a city were analyzed in order to ensure drinking water safety.

Methods To analyze the monitoring data of drinking water (sourced from Taihu), and to evaluate the data according to the Standards for Drinking Water Quality(GB 5749-2006).

Results The disqualification rate of 1 780 water samples monitored in these five years was 6.1%; the disqualification rate for treated water and tap water were 2.7% and 7.2, respectively (χ²=435.056, P=0.000). Distribution of water quality was various yearly and quarterly. Current disqualification rate was significantly lower than the past (χ²=40.078, P=0.000); the disqualification rate in the third quarter was obviously higher than others (χ²=10.215, P=0.017).The Disqualification rate of all items was 0.33%.The most unqualified item was total bacteria counts (its disqualification rate was 2.9%); and the next item was toxicology (disqualification rates of aluminum, Bromo-dichloro-methane and Monobromo-dichloro-methane were all 2.5%).

Conclusions Currently, the quality of drinking water sourced from Taihu has basically met the requirement of GB 5749-2006 in this area. The monitoring strategy matched with regional water supply was the key point to ensure the safety of regional drinking water supply. For ensuring the safety of drinking water, a systematic, consecutive, sharing, networking, forecasting and early warning, and sustainability should be reflected in the project.