Investigation on organism pollution of various water resources after devastating earthquake in Yingxiu Town of Wenchuan County

Objective:To investigate the organism pollution of various water resources in Yingxiu Town after earthquake,so as to provide evidence for safe and permanent drinking water resources.Methods:From the 32nd to the 37th day after Wenchuan Earthquake,the water samples were collected from different water resources around the camping areas of the disaster refugees and military rescuers in Yingxiu Town;the resources included the mountain spring(6 sites),valley water(4 sites),surface water(Min river,Pitiao river and the junction of the former 2 rivers),rain water(18 sites),water purified by military vehicles(7 sites)and chlorine-disinfected water(7 sites).The 85-type water examination kits were used to examine ammonia nitrogen and nitrite nitrogen contents,pH value,turbidity(observation with naked eye),smelling,and residual chlorine of the water samples.Bottled drinking water served as control.Average values and chi-square test were used for analysis of difference.Results:Two of the 4 valley water samples and all the surface water samples had a ammonia nitrogen content of 0.10-0.18 mg/L;the contents of ammonia nitrogen and nitrite nitrogen were similar between other water resources except for the above mentioned 2 valley water samples and the surface water samples.However,the average ammonia nitrogen contents in the directly harvested rain samples and rain samples dropped from the tents were 0.625 mg/L and 0.913 mg/L,respectively,both significantly higher than that in the control(0 mg/mL)and exceeding the safe standard(0.05 mg/L).Nitrite nitrogen was detectable in some water samples dropped from the tents.The average pH value in direct rain water samples(6.07)was significantly lower than those in the springs(6.55),the valley water(6.60)and the surface water(6.63).Residual chlorine was not found in 4 of the 7 disinfected water sites.Conclusion:No recent or past organism pollution is found in the spring.The valley water and river water can be used as sources of drinking water after purification and disinfection.High ammonia nitrogen content in the direct rain samples suggests serious air pollution,mainly recent pollution.It is also indicated that the disinfection of drinking water is not up to the standard.