Investigation on a Water Contamination Accident in Tuojiang River Caused by Industrial Wastewater / 环境与健康杂志

ABSTRACT

Objective To investigate a water contamination accident caused by industrial wastewater during Feb 27th-29th ,2004,in Tuojiang river, analyze the variation of sanitary quality of drinking water during and after the accident. Methods After the occurrence of the accident,consecutive surveillance and analyses were done to discover the variation of the levels of amino-nitrogen,nitrite and nitrate in source water and finished water of Jianyang Water Works and Neijiang No 2 Water Works,which located at the lower reaches of Jianyang. Results The levels of amino-nitrogen in source water and finished water of Jianyang Water Works reached the first peak [(47.04?2.48)?(45.97?2.37)mg/L]at the 3rd day(March 3rd) after the end of discharge of industrial wastewater from contamination source,decreased at the 4th day ,reached the second peak at the 5th day[(42.26?2.88)?(39.50?2.64)mg/L], then decreased gradually, presented the normal levels at the 11th day[(0.54?0.10)?(0.30?0.12)mg/L]. The levels of nitrite in source water and finished water of Jianyang Water Works reached the first peak [(2.09?0.23)?(0.91?0.15)mg/L] at the 2 nd-3rd day after the end of discharge of industrial wastewater from contamination source,decreased at the 4th day ,reached the second peak at the 5th day[(2.18?0.33),(0.61?0.16)mg/L], then decreased gradually,presented the normal levels at the 11th day[(0.16?0.07)?(0.02?0.01)mg/L]. The levels of nitrate in source water and finished water of Jianyang Water Works(3.56～9.15 mg/L) didn't exceed the standard ruled the Sanitary Standard for Drinking Water (2001) throughout the duration of accident. The levels of amino-nitrogen and nitrite in source water and finished water of Neijiang No.2 Water Works both exceeded the related standards, the levels of nitrate met the requirement of the Sanitary Standard for Drinking Water (2001) during the period from the first day to the third day after the end of discharge of industrial wastewater from contamination source. From the forth day to the 25 th day, Neijiang No.2 Water Works was changed to be supplied by the Five-star reservoir,and produced safe and sanitary finished water meeting the requirement of the Sanitary Standard for Drinking Water (2001). Conclusion This wastewater contamination accident seriously deteriorates the quality of drinking water in Jianyang and Neijiang.