Objective To investigate the Oncomelania hupensis snail control effect of schistosomiasis control engineering in marshland within Wuhan City. Methods The engineering measures including surface barrier removal,molluscicide,flatting surface,topsoil stripping,topsoil covering and ditch renovation were applied to transform Hankou marshland. Then the corre-sponding technical parameters of engineering measures were put forward. The situation of snails was analyzed before and after the transform project. Results The total length and area of the project were 6015 m and 87.21 hm2,respectively,including 17.44 hm2 of topsoil landfill,52.08 hm2 of topsoil covering and 23 new ditches. After the transformation,the average length of the new groove,the groove top width,groove depth,height difference,and the average values of slopes and ditch bottom slope were all increased,while the average values of the width and height of the ditch were decreased. At the same time,the marsh-land beach surface had a new slope that the embankment was higher than the river and no living O. hupensis snails were found then. Conclusions The snail breeding environment in Hankou marshland has been effectively changed by the project. Howev-er,the constant monitoring and engineering management are still needed to consolidate the effect.

Objective: To analyze the exposure level and the geographical distribution trend of toxicological indicators of rural drinking water in Shandong Province. Methods: The drawing method was used to randomly select no less than 60% villages and towns from 137 counties (cities, districts) of 17 cities in Shandong Province in 2015, and then 1-3 rural centralized water supply units were selected according to the circumstance of rural centralized water supply units in each village and town. In total, 735 villages and towns, 1 473 rural centralized water supply units were selected, and 1 473 water samples were collected. The water treatment process, water supply population and other circumstances of the rural centralized water supply units were investigated, the water quality was monitored, the content of toxicological indicators of drinking water in different areas was compared, and the trend surface isogram of excessive toxicological indicators was drawn. Results: The qualified rate of toxicological indicators in 1 473 water samples was 83.64% (n=1 232). The main toxicological indicators that affected the qualified rate of toxicological indicators of drinking water in rural areas in Shandong Province were nitrate and fluoride. The excessive rate of fluoride was 5.70% (n=84) and the exposed population was 1 736 709 (4.22%). The excessive rate of nitrate (as nitrogen) was 12.29% (n=181) and the exposed population was 1 393 612 (3.39%). The P₅0 content of fluoride in the eastern, middle and western regions was 0.24, 0.29 and 0.59 mg/L, respective;which was higher in the western region than in the east and the middle regions (P<0.05). There was no significant difference between the eastern and the middle regions (P>0.05). The P₅₀ content of nitrate (as nitrogen) in the eastern, middle and western regions was 8.00, 7.48, and 2.00 mg/L, which was higher in the eastern and middle regions than in the west region (P<0.05), there was no significant difference between the eastern and the middle regions (P>0.05). The trend surface isogram of nitrate and fluoride content showed that the content of nitrate (as nitrogen) in rural drinking water in the eastern region was significantly higher than that in the western region, especially there was a high peak area in the northeastern region, and this high content distribution extended diagonally to the central region, while the other regions were in a relatively low range. The content of fluoride in rural drinking water in the western region was significantly higher than that in the eastern region, and there were high peaks in the southwest and northwest regions, and the other regions were in a relatively low range. Conclusion The high exposed toxicological indicators in rural drinking water in Shandong Province were nitrate (as nitrogen) and fluoride, and their distribution showed obvious geographical distribution trend.