[Preliminary study of toxicity of niclosamide ethanolamine salt on wetland creatures along lower reaches of Yangtze River in Nanjing City].

OBJECTIVE: To understand the impact of niclosamide ethanolamine salt on the Yangtze River wetland creatures, so as to provide an evidence for the environmental impact assessment of the Oncomelania hupensis control measures. METHODS: Eriocheir sinensis, Procambarus clarkii, freshwater mysis and Bellamya aeruginosa were chosen as the test organisms from the lower reaches of the Yangtze River in Nanjing City, and they were immersed in the different concentrations of niclosamide ethanolamine salt solution for 24-96 h. The mortality rates and LC50 values were calculated. RESULTS: There was only 1 death (with a mortality rate of 8.33%) of P. clarkia immersed in niclosamide ethanolamine salt with the concentration of 400 mg/L for 96 h. There was no death of the E. sinensis immersed in niclosamide ethanolamine salt with the concentration of 640 mg/L for 96 h. The LC50 values were 2.170 4, 1.303 6, 1.013 1 mg/L and 0.720 5 mg/L respectively when the freshwater mysis were immersed in the solution for 24, 48, 72 h and 96 h. The LC50 values were 1.173 5, 0.642 1, 0.477 3 mg/L respectively when the B. aeruginosa were immersed in the solution for 24, 48, 72, 96 h. CONCLUSIONS: The impacts of niclosamide ethanolamine salt on the different wetland creatures are different. E. sinensis and P. clarkii have high resistance to niclosamide ethanolamine salt. However, niclosamide ethanolamine salt shows heavy toxicity on the freshwater mysis and Bellamya aeruginosa.

[Effect of water storage and aquaculture on Oncomelania hupensis control in tidal flats wetlands of islet-beach type area of Dantu section of lower reaches of Yangtze River].

OBJECTIVE: To evaluate the effect and the benefits of the projects of water storage and aquaculture on Oncomelania hupensis snail control in the tidal flats wetlands of islet-beach type area of lower reaches of the Yangtze River. METHODS: The projects of water storage and aquaculture on 0. hupensis snail control were implemented in the tidal flats wetlands of islet-beach type of lower reaches of the Yangtze River. The breed situation of the snails was investigated by the conventional method before and after the project implementation and the effect of control and elimination of the snails by the projects were evaluated. At the same time, the cost-benefit analysis of two projects among them was performed by the static benefit-cost ratio method. RESULTS: All of 0. hupensis snails were eliminated in the first year after the implementation of seven water storage and aquaculture projects. The costs of detection and control of snails saved by each project was 69.20 thousand yuan a year on average. The annual net benefits of the "Nanhao Group 10 beach" project and "Wutao Group 6-14 beach" project were 2 039.40 thousand yuan and 955.00 thousand yuan respectively, and the annual net benefit-cost ratios were 1.09: 1 and 1.07: 1 respectively. CONCLUSION: The O. hupensis snails could be rapidly eliminated by the water storage and aquaculture, and the economic benefit is obvious, but the wetland ecological protection and flood control safety should be considered in the tidal flats wetlands of islet-beach type area of lower reaches of the Yangtze River.

[Study on distribution and countermeasures of Oncomelania snails in beach wetlands of Runzhou section of lower reaches of Yangtze River].

OBJECTIVE: To understand the distribution of the river beach wetlands and Oncomelania snails in the lower reaches of the Yangtze River, and explore the countermeasures of snail control. METHODS: The river beach wetlands outside the Yangtze River levee were investigated and classified according to the hierarchical and classification system of wetlands of China. The snail survey was carried out in the beach wetlands of Runzhou section of lower reaches of the Yangtze River from 2004 to 2013. The change trend of snail areas and the densities was analyzed in the wetlands. RESULTS: The river beach of Runzhou section of lower reaches of the Yangtze River belongs to the riverine wetland. There was Oncomelania snail breeding except the permanent water area. At present, there were natural wetlands of 1303.0 hm2, human-made wetlands of 1479.0 hmb2 and wetland function changes of 1059.0 hm2 in the river beach of Runzhou section. There was the snail area of 181.4 hm2 in the natural wetland in 2013. The area of snail control by the molluscicide and environmental modification was 4624.55 hm2 from 2004 to 2013. The decline rates of snail areas and densities were 66.53% and 77.66% respectively. The existing Oncomelania snails were distributed in the natural wetlands. CONCLUSION: The human-made wetland is helpful to snail control. The snail control in the river beach wetlands should attach a great importance to the protection of wetland ecology.

[Further study on possibility of diffusion of Oncomelania hupensis with water in river channels of the east route of South-to-North Water Diversion Project].

OBJECTIVE: To study the drifting law of floats and potential risks of Oncomelania hupensis diffusion in the water diversion rivers of the east route of South-to-North Water Diversion Project. METHODS: The O. hupensis snails in the river channels were monitored by the salvage method and snail luring method with rice straw curtains, and the diffusion possibility of snails along with water was assessed through the drift test of floats with GPS. RESULTS: In the flood seasons from 2006 to 2013, totally 8 338.0 kg of floats were salvaged, and 2 100 rice straw curtains were put into water in the Li Canal and Jinbao shipping channel, but no Oncomelania snails were found. The drift test of floats with GPS before water diversion showed that the flow velocity on water surface (northbound) was 0.45 m/s, the average drift velocity of the floats was 0.56 - 0.60 m/s, and the average drift distances each time were 999.70 - 1 995.50 m in the Gaoshui River section, while there were no obvious drift in Jinbao shipping channel section. During the water diversion period, the flow velocity on water surface (northbound) was 0.45 m/s, the average drift velocity of the floats was 0.35 - 0.41m/s, and the average drift distances each time were 1 248.06 -1 289.44 m in the Gaoshui River, while in Jinbao shipping channel section, the flow velocity on water surface was 0.28 m/s, the average drift velocity of the floats was 0.25 - 0.27 m/s, and the average drift distances each time were 477.76 - 496.38 m. The drift test showed that the floats gradually closed to the river bank as affected by water flow, wind direction and ship waves, when blocked by the reeds, water plants or other obstacles, and they would stopped and could not continue to drift without outside help. CONCLUSIONS: There are no Oncomelania snails found in the river channels of the east route of South-to-North Water Diversion Project. The drifting distance of the floating debris along with the water is restricted by the flow rate and shore environment.

Schistosoma japonicum risk in Jiangsu province, People's Republic of China: identification of a spatio-temporal risk pattern along the Yangtze River.

The risk for Schistosoma japonicum infection in Jiangsu province, People's Republic of China, was investigated by a mouse bioassay. Various investigations were conducted in the period 2009-2011 with the presentation here representing the summary of the results from 45-50 sites in the marshlands along the Yangtze River's course through the province. Indices representing three aspects of the infection were collected to assess risk: (i) the proportion of sentinel points where at least one mouse infection was recorded; (ii) the proportion of infected mice at each of these sites; and (iii) the average worm burdens. Directional distribution analysis and scan statistics were used to explore the spatio-temporal risk pattern. The spatial distribution was oriented along the Yangtze River and the directional distributions for the proportion of infected mice and mean worm burdens were similar for the positive sentinel sites. Four statistically significant clusters were detected in 2009, but only one in 2010 and 2011, respectively. Temporal windows for infection risk were seen in June and September. The study illustrates the utility of spatio-temporal analysis in assessing the risk for schistosomiasis. This approach should be useful with respect to surveillance and response that can be expected to be increasingly applied when moving from morbidity control to transmission control.

Spatio-temporal analysis to identify determinants of Oncomelania hupensis infection with Schistosoma japonicum in Jiangsu province, China.

BACKGROUND: With the successful implementation of integrated measures for schistosomiasis japonica control, Jiangsu province has reached low-endemicity status. However, infected Oncomelania hupensis snails could still be found in certain locations along the Yangtze river until 2009, and there is concern that they might spread again, resulting in the possible re-emergence of infections among people and domestic animals alike. In order to establish a robust surveillance system that is able to detect the spread of infected snails at an early stage, sensitive and reliable methods to identify risk factors for the establishment of infected snails need to be developed. METHODS: A total of 107 villages reporting the persistent presence of infected snails were selected. Relevant data on the distribution of infected snails, and human and livestock infection status information for the years 2003 to 2008 were collected. Spatio-temporal pattern analysis including spatial autocorrelation, directional distribution and spatial error models were carried out to explore spatial correlations between infected snails and selected explanatory factors. RESULTS: The area where infected snails were found, as well as their density, decreased significantly between 2003 and 2008. Changes in human and livestock prevalences were less pronounced. Three statistically significant spatial autocorrelations for infected snails were identified. (i) The Moran's I of infected snails increased from 2004 to 2007, with the snail density increasing and the area with infected snails decreasing. (ii) The standard deviations of ellipses around infected snails were decreasing and the central points of the ellipses moved from West to East. (iii) The spatial error models indicated no significant correlation between the density of infected snails and selected risk factors. CONCLUSIONS: We conclude that the contribution of local infection sources including humans and livestock to the distribution of infected snails might be relatively small and that snail control may limit infected snails to increasingly small areas ecologically most suitable for transmission. We provide a method to identify these areas and risk factors for persistent infected snail presence through spatio-temporal analysis, and a suggested framework, which could assist in designing evidence based control strategies for schistosomiasis japonica elimination.

[Effect of environmental change in marshland after implementation of Three Gorges Reservoir Project on schistosomiasis in Jiangsu Province].

OBJECTIVE: To investigate the effect of environmental change in marshland after the implementation of the Three Gorges Reservoir Project on schistosomiasis in Jiangsu Province. METHODS: The hydrologic data of Nanjing City in Jiangsu section of the Yangtze River, and the data regarding the marshlands, the snail status and schistosomiasis morbidity in areas adjacent to the Yangtze River in Jiangsu Province were collected, and field snail surveys were performed in typical marshlands. RESULTS: Following the implementation of the Three Gorges Reservoir Project, the water level in Nanjing section of the Yangtze River appeared a year-dependent gradual decline tendency. The mean peak water level on January to March, 2012 (spring) increased by 0.41 m as compared to that before the construction of the project in 2002, while the peak water level on April to December, 2012 decreased by 0.32 m as compared to that before the construction of the project in 2002. The endemic situation of schistosomiasis showed a decline tendency in areas adjacent to the Yangtze River in Jiangsu Province. The area with infected snails along the Yangtze River was 0, the positive rates of serological tests and parasitological tests of the population were 0.73% and 0.004%, respectively in 2012. CONCLUSIONS: Both the schistosomiasis morbidity and snail status appear a decline tendency in areas adjacent to the Yangtze River along the lower reaches of the Yangtze River, Jiangsu Province after the implementation of the Three Gorges Reservoir Project.

[Surveillance of endemic situation of schistosomiasis in Gaoyou sections in east route of South-to-North Water Diversion Project before water transfer].

OBJECTIVE: To understand the endemic situation of schistosomiasis and the distribution of Oncomelania hupensis snails in Gaoyou sections in the east route of the South-to-North Water Diversion Project before water transfer. METHODS: The Grand Canal, the Sanyang River and the range of 3 kilometers of both sides of the rivers were chosen as the surveillance area in the Gaoyou sections in the east route of the South-to-North Water Diversion Project, and the Gaoyou Lake area adjacent to the east route was also chosen as the surveillance area. The human and livestock schistosomiasis and Oncomelania hupensis snails were monitored by the conventional method. Three underwater snail surveillance sites were set up in the Grand Canal and the Sanyang River respectively, and the net salvage method and the method of attracting snails with rice straw curtains were used to survey the snails underwater in the surveillance sites. RESULTS: The schistosome infected snails, the human and livestock schistosomiasis were not found in the Gaoyou sections in the east route of the South-to-North Water Diversion Project from 2006 to 2012. The snail areas were on the decline in the Grand Canal. The snail was not found in the Sanyang River. A total of 270 kg floatage was refloated and 720 pieces of rice straw curtains were placed in the surveillance sites, and there were no snails in the floatage and the rice straw curtains. CONCLUSION: There is no evidence showing that the snails spread to northward in the Gaoyou sections in the east route of the South-to-North Water Diversion Project.

[Effect of sand buried on elimination of Oncomelania hupensis snails in marshland along Yangtze River in Jiangdu District, Jiangsu Province].

OBJECTIVE: To evaluate the effect of sand buried on the elimination of Oncomelania snails in the marshland along the Yangtze River downstream. METHODS: The areas along the Yangtze River were chosen as the investigated objects in Jiangdu District, Jiangsu Province. The datum review and field investigations were used to observe the change of snail area after the sand buried. RESULTS: There were 11 sand buried projects along the Yangtze River in Jiangdu District, Jiangsu Province. The snail areas decreased by 93.73% after the sand buried. CONCLUSION: The sand buried is an effective method of snail control in the marshland along the Yangtze River. This method can be combined with economic construction and development projects for popularization and application.

[Technology of preventing oncomelania snail diffusion in east route of South-to-North Water Diversion Project II. Effect of sand buried and reed protection on snail control in area of water source].

OBJECTIVE: To evaluate the effect of sand buried and reed protection on Oncomelania snail control in the area of water source of the east route of South-to-North Water Diversion Project. METHODS: The Oncomelania snail eggs were counted after the snails raised seven days in the sand of different contents in the spawning period. The survival of the snails was observed when the snails were raised on the sand surface in the laboratory. The change of the densities of living snails and reed growth were observed in the area of water source. RESULTS: The snails did not lay eggs in the pure sand environment. There was a negative correlation between the number of snail eggs and the content of sand (r = -0.965, P = 0.008). The mortality rates of the snails were increasing with the increase of the time in the sand environment. The mortality rates of the snails were 96.00% and 100% when the snails were raised 3 months and 6 months around 25 degrees C respectively. The field test showed that the snails were not discovered after the sand buried, the second spring, after the flood season, and the third spring. However, the density of living snails of the control group dropped by 93.65% 2 weeks after using molluscicide, but increased by 100% and kept in 0.37 snails/0.1 m2 after the flood season and the third year spring, respectively. The reed growth was good in the second spring after the sand buried. CONCLUSIONS: The sand environment is unfavorable for laying eggs and survival of the snails. The sand buried method has the effects of snail control and reed protection. In addition, the method could also prevent the snail spread in the flood season.

A real-time platform for monitoring schistosomiasis transmission supported by Google Earth and a web-based geographical information system.

A basic framework for the rapid assessment of the risk for schistosomiasis was developed by combining spatial data from Google Earth® with a geographical information system (GIS) package, bundling the modules together with an Internet connection into a WebGIS platform. It operates through functions such as "search", "evaluation", "risk analysis" and "prediction" and is primarily aimed to be a dynamic, early-warning system (EWS) providing user-friendly, evidence-based, near real-time awareness of the status of an important endemic disease. It contributes to rapid information-sharing at all levels of decision-making, facilitating "point-of-care" response, i.e. treatment provided at newly discovered transmission sites. The experience using the platform is encouraging and it has the potential to improve support systems and strengthen schistosomiasis control activities, in particular with regard to surveillance and EWS. It can quickly and intuitively locate early, high-risk areas, retrieve all important data needed as well as provide detailed, up-to-date information on the performance of the control programme. This WebGIS, the first of its kind in the People's Republic of China, is not only applicable for schistosomiasis but can easily be adapted for improving control of any endemic disease in any geographical area.

[Study on potential risks of schistosomiasis transmission in Grand Canal West water diversion route of eastern route project of South-to-North Water Diversion Project].

OBJECTIVE: To understand the potential risks of Oncomelania hupensis diffusion and schistosomiasis transmission in the Grand Canal west water diversion route of the eastern route project of the South-to-North Water Diversion Project. METHODS: The engineering layout from Nanyun west floodgate to Hongze Lake, the aquaculture along Hongze Lake, and the data of hydrology and transferred water were investigated. The investigations on Oncomelania hupensis and schistosomiasis were carried out in the surveillance sites of Jinbao Channel and Hongze Lake. The possibilities of snail spreading and schistosomiasis transmission were researched. RESULTS: Oncomelania snails lacked their breeding environment and ecological condition in the Hongze Lake region. The engineering facilities of the Jinhu and Hongze pumping stations went against the snail spreading. The water levels at all steps decreased gradually from Hongze Lake to Jinbao Channel. Therefore, the pumping stations were necessary when the water transferred to Hongze Lake. The multi-year average diverted water volume reached 2.558 billion cubic meters a year in the Jinbao Channel. Of the total diverted water volume, there was 75% of the volume in drought years. The Oncomelania snails were not found in the surveillance sites of the Jinbao Channel and the Hongze Lake region from 2008 to 2011. A total of 3 088 residents were examined with the serology tests and the positive rate was 0.29% in 2008. Totally 4 758 overwater flow people were examined with the serology tests and the positive rate was 2.42% from 2008 to 2011. The serum positive rate was higher in the overwater flow people than that in the residents (chi2 = 0.083, P < 0.01). The stool examinations were all negative in the above mentioned serum positive people. CONCLUSIONS: The Hongze Lake area has still no Oncomelania snail breeding and schistosomiasis endemic so far. There are also no schistosomiasis re-prevalent signs in the Jinbao Channel area where schistosomiasis was once prevalent. The Oncomelania snail breeding and diffusion, and schistosomiasis endemic are unlikely to appear in the Grand Canal west water diversion route of the eastern route project of the South-to-North Water Diversion and Hongze Lake area.

[Effect of water conservancy schistosomiasis control projects in rivers and estuaries connecting with the Yangtze River on Oncomelania snail control].

OBJECTIVE: To evaluate the effect of the water conservancy schistosomiasis control projects in rivers and estuaries connecting with the Yangtze River on Oncomelania snail control. METHODS: Three water conservancy schistosomiasis control projects of Laobianmin River, Panjia River and Bianmin River were chosen for the objects of the study. The concrete slope protection and the overflow dam, the concrete slope protection and the check sluice, and the simple concrete slope protection were built respectively in above mentioned three rivers. The changes of the area with snails and density of snails were investigated before and after the interventions, and the results were compared among the three projects. RESULTS: In the condition of the routine snail control with the molluscicide, the snails were eliminated in the main riverway of the Laobianmin River, but the snails still existed in the target protected area (tributaries of the river and irrigation areas); the snails were eliminated in the Panjia River and its irrigation areas; in the Bianmin River, the areas with snails dropped by 89.22% in the main river and still remained in the tributaries and irrigation areas after the project implementation. CONCLUSIONS: The sluice and overflow dam more contribute to control and eliminate snails in the project areas and the target protected areas in the rivers and estuaries connecting with the Yangtze River. The priority of consideration should be given to the water level control and prevention of snail spreading in the water level instability rivers connecting with the Yangtze River.

[Study on surveillance and early-warning system of schistosomiasis in first phase of east route of South-to-North Water Diversion Project. III. Indexes of surveillance and early-warning and risk assessment].

OBJECTIVE: To establish the index system of surveillance and early-warning on schistosomiasis and to provide the scientific basis for risk assessment and emergency plan in first phase of east route of South-to-North Water Diversion Project. METHODS: The Delphi method and the multidimensional synthetic evaluation were used in the evaluation of indexes of surveillance and early-warning on schistosomiasis in the east route of the project. RESULTS: There were 53 indexes evaluated in the index system, and among them, there were 3 first grade indexes, 10 second grade indexes and 40 third grade indexes. The indexes on Oncomelania snails were the most important. According to the habitation position of snails, the four grades on surveillance and early-warning of schistosomiasis were established in the east route. The grade I of the early-warning meant that snails crossed the first level of the pumping station. The grade II meant that snails crossed N 32 degrees 54'. The grade III meant that snails crossed N 33 degrees 03' or Jinhu pumping station. The grade IV meant that snails crossed N 33 degrees 15' or Hongze Station. Other 4 indexes on schistosome infection in people and livestock were confirmed as indicative indexes. According to the relationship among the indexes, the evaluation methods were determined on the risk of schistosomiasis transmission. CONCLUSIONS: The index system of surveillance and early-warning and the methods of risk assessment of schistosomiasis have been confirmed in first phase of east route of South-to-North Water Diversion Project. The primary index is related to snails and the supplementary is related to schistosome infection in people and livestock in the system.

[Technology of preventing Oncomelania snail diffusion in east route of South-to-North Water Diversion Project. I. Field test of blocking diffusion of Oncomelania snails with blocking network via collecting water from middle layer].

OBJECTIVE: To evaluate the effectiveness of blocking diffusion of Oncomelania snails with the blocking network via collecting water from middle layer. METHODS: According to the principle of the installation preventing snails via collecting water from middle layer without snails, the blocking network was manufactured. The field test of the blocking diffusion of snails with the blocking network was carried out in the electric pumping station and the irrigation located in the area with snails. The snails stained were put into the water inlet of the pump when the pump was actuating, and the snails pumped were observed during the test period. The cost of the test was also calculated. RESULTS: The rate of blocking diffusion of snails with the blocking network was 100%, and the direct costs were only 11 030 CNY. CONCLUSIONS: The blocking network via collecting water from middle layer has good effect for prevention of snail dispersal. It is simple for manutacturing and installation, and suitable for emergency blocking diffusion of snails in the east route of South-to-North Water Diversion Project and the electric pumping station with snails.

[Conditions of schistosomiasis laboratories at county level].

OBJECTIVE: To understand the conditions of schistosomiasis laboratories at county level, so as to supply the information for diagnostic capacity building. METHODS: A questionnaire survey was conducted at 40 random selected counties which were in charge of national surveillance for schistosomiasis. The information of staffs, areas of laboratories, equipment configuration and diagnostic methods from each laboratory were collected. The serum specimens and Kato-Katz thick smears from the national surveillance sites were randomly selected and retested by provincial staffs to evaluate the testing ability of the personnel. RESULTS: The average age of laboratory staffs was 40.93 +/- 9.56 years old, 69.39% of staffs were older than 35 years, 86.22% of them had education background below bachelor degree. Except missed professional titles of 4 persons, the staffs with primary, middle and high professional titles accounted for 56.63%, 39.29% and 2.04%, respectively. The laboratory areas varied greatly while independent schistosomiasis stations had the lowest areas with 52.81 +/- 40.08 m2, and the equipment configurations of laboratories were in a low level. The consistency rates of primary test and reexamination for serum specimens and thick smear slides were 95.89% and 99.53%, respectively, with the Kappa value over 0.90. Nine immunodiagnostic kits were used in these laboratories, and Kato-Katz technique and miracidium hatching technique were the main parasitological methods. CONCLUSIONS: The personnel structure of laboratories at primary prevention and treatment facilities for schistosomiasis is unreasonable, while the basic infrastructure of laboratories is backward and the use of diagnostic assays/methods is disordered. The diagnostic capacity building should be strengthened, and the construction and management of schistosomiasis laboratories should be standardized.

[Surveillance of Oncomelania hupensis snails in Baoying and Gaoyou sections of Li Canal in east route of South-to-North Water Diversion Project].

OBJECTIVE: To understand the distribution and diffusion of Oncomelania hupensis snails in the Baoying and Gaoyou sections of the Li Canal in the east route of the South-to-North Water Diversion Project. METHODS: The retrospective survey method was used to investigate the distribution and diffusion of snails in the Baoying and Gaoyou sections of the Li Canal, the conventional survey and the methods of salvage of water and attracting snails were used to detect the distribution of snails in river banks and water. RESULTS: The earliest findings of snails in the Gaoyou section of the Li Canal was in 1955, the northernmost distribution of snails was Dilong ferry at the west dam and east slope of the Li Canal. The dynamic surveillance in the Gaoyou section of the Li Canal from 2001 to 2010 showed that the snail status was of low density and low fluctuation of area, and the distribution range was 119 degrees 24' 36" -119 degrees 25' 34", 32 degrees 48' 30" -32 degrees 54' 05". From 2006 to 2010, the snails were not found by the methods of salvage of water and attracting snails in the surveillance in the Baoying and Gaoyou sections of the Li Canal. CONCLUSIONS: So far, there is no evidence showing that the snails spread to northward in the Li Canal, however, it is still necessary to carry out the surveillance of snails and schistosomiasis in the east route of the South-to-North Water Diversion Project.

[Impact of simulation operation high water level on Oncomelania hupensis natural growth in water diversion rivers of east route of South-to-North water Diversion Project].

OBJECTIVE: To verify the impact of operation high water level on Oncomelania hupensis natural growth in the water diversion rivers of the east route of South-to-North Water Diversion Project. METHODS: The data of the daily mean water level were investigated in the stilling pool of Jiangdu Pumping Station during the water diversion under the emergency anti-drought, and the water level data of the previous year served as the control. The dynamic of natural growth of O. hupensis snails was observed before and after the high water level in the beach wetlands of the stilling pool of Jiangdu Pumping Station. The water level of emergency anti-drought was as simulation operation water level of the east route of South-to-North Water Diversion Project in the stilling pool, and then the effects of operation water level on O. hupensis natural growth in the water diversion rivers of the east route of South-to-North Water Diversion Project were studied. RESULTS: The altitude of the beach wetlands was 6.4 to 7.2 meters in the stilling pool of Jiangdu Pumping Station. The water diversion was 255 days continuously and the pumped water was 6.235 billion cubic meters in the Jiangdu Pumping Station from November 2010 to July 2011. There were 216, 136 days and 39 days when daily mean water level were more than or equal to 7.2, 7.6 and 8.0 meters during the water diversion, respectively. The snail densities were 0.856 snails/0.1m2 and 0.0153 snails/0.1m2, respectively, before and after the No.3 beach wetlands flooded in the stilling pool of Jiangdu Pumping Station. The densities of living snails decreased by 98.21%, and there was no any progeny of snail. The snails were not detected in other environment of the stilling pool. CONCLUSION: The operation high water level can effectively restrain snail breeding in the water diversion rivers of the east route of South-to-North Water Diversion Project.

Landfills in Jiangsu province, China, and potential threats for public health: leachate appraisal and spatial analysis using geographic information system and remote sensing.

Waste disposal is of growing environmental and public health concern in China where landfilling is the predominant method of disposal. The assessment of potential health hazards posed by existing landfills requires sound information, and processing of a significant amount of spatial data. Geographical information system (GIS) and remote sensing (RS) are valuable tools for assessing health impacts due to landfills. The aims of this study were: (i) to analyze the leachate and gas emissions from landfills used for domestic waste disposal in a metropolitan area of Jiangsu province, China, (ii) to investigate remotely-sensed environmental features in close proximity to landfills, and (iii) to evaluate the compliance of their location and leachate quality with the relevant national regulations. We randomly selected five landfills in the metropolitan areas of Wuxi and Suzhou city, Jiangsu province, established a GIS database and examined whether data were in compliance with national environmental and public health regulations. The leachates of the sampled landfills contained heavy metals (Pb, As, Cr(6+) and Hg) and organic compounds in concentrations considered harmful to human health. Measured methane concentrations on landfill surfaces were low. Spatial analysis of the location of landfills with regard to distance from major water bodies, sensible infrastructure and environmental conditions according to current national legislation resulted in the rejection of four of the five sites as inappropriate for landfills. Our results call for rigorous evaluation of the spatial location of landfills in China that must take into consideration environmental and public health criteria.

[Observation on the amount of oxygen consumption by Oncomelania hupensis under low temperature].

OBJECTIVE: To observe hibernation phenomena of Oncomelanai hupensis and explore the way of inducing the hibernation in laboratory. METHODS: Snails, O. hupensis hupensis, were collected from marshland of Jiangsu. The snail hibernation was induced by the way of cultivation at a mimic natural environment in the laboratory with gradually changing temperature. The amount of oxygen consumed by snails was tested by iodine titration, and their hibernation was tested by pin puncture followed by warm water. RESULTS: There was no significant difference on the rate of snail hibernation when the temperature was reduced by 1 degree C per 24 hrs and by 1 degree C per 48 hrs. The hibernation rate increased with the decreasing temperature. There was a significant regression relationship between hibernation rate and temperature with R2 = 0.967 (F = 207.72, P < 0.01). The temperature for 50% snails at hibernation (ET50) was at 5.87 degrees C with 95% confidence limit of 5.32-6.23 degrees C. The amount of oxygen consumed by snails declined with reduced temperature, there was a significant regression relationship between oxygen consumption and temperature with R2 = 0.963 (F = 182.18, P < 0.01). A significant regression relationship was also shown between oxygen consumption and hibernation rate (R2 = 0.916, F = 75.88, P < 0.01). CONCLUSION: Snail hibernation can be induced by the way of gradually decreasing temperature, and pin puncture or warm water resuscitation can be used to determine the status of snail hibernation.