δ15N and nutrient stoichiometry of water, aquatic organisms and environmental implications in Taihu lake, China.

Nitrogen pollution has become a worldwide problem and the source identification is important for the development of pertinent control measures. In this study, isotope end members (rain, nitrogen fertilizer, untreated/treated sewage), and samples (river water discharging to Taihu lake, lake water, aquatic organisms of different trophic levels) were taken during 2010-2015 to examine their δ15N values and nutrient stoichiometry. Results indicated that phytoplankton (primary producers), which directly take up and incorporate N from the lake water, had a similar δ15N value (14.1‰â€¯±â€¯3.2) to the end member of treated sewage (14.0‰â€¯±â€¯7.5), and the most frequently observed δ15N value in the lake water was 8-12‰, both indicating the dominant impact of the sewage discharge. Relationship analysis between N isotope value of nitrate and nitrate concentration indicated that different N cycling existed between the algae-dominated northwest lake (NW) and the macrophyte-dominated southeast lake (SE), which is a result of both impacts of river inputs and denitrification. Our nutrient stoichiometry analysis showed that the lake water had a significantly higher N:P ratio than that of algae (p < 0.05), suggesting that N is available in excess relative to the amount demanded by the algae. The long-term trend of the socio-economic development in the watershed further confirmed that the rapid population increase and urbanization have resulted in a great change in the N loading and source proportion. We suggest that although P control is necessary in terms of eutrophication control, N pollution control is urgent for the water quality and ecological recovery for Taihu lake.

Response of sediment calcium and magnesium species to the regional acid deposition in eutrophic Taihu Lake, China.

Acid deposition causes carbonate dissolution in watersheds and leads to profound impacts on water chemistry of lakes. Here, we presented a detailed study on the seasonal, spatial, and vertical variations of calcium and magnesium species in the overlying water, interstitial water, and sediment profiles in eutrophic Taihu Lake under the circumstance of regional acid deposition. The result showed that both the acid deposition and biomineralization in Taihu Lake had effects on Ca and Mg species. In the lake water, calcium carbonate was saturated or over-saturated based on long-term statistical calculation of the saturation index (SI). On the sediment profiles, significant difference in Ca and Mg species existed between the surface sediment (0-10 cm) and deeper sediments (>10 cm). The interstitial water Ca2+ and Mg2+, ion-exchangeable Ca and Mg in the surface sediment were higher than those in the deeper sediment. In the spring, when the acid deposition is more intensive, the acid-extracted Ca and Mg in the surface sediment were lower than that in the deeper sediment in the northwest lake, due to carbonate dissolution caused by the regional acid deposition. Spatially, the higher concentration of acid-extracted Ca and Mg in the northwest surface sediment than that in the east lake was observed, indicating the pronounced carbonate biomineralization by algae bloom in the northwest lake. Statistical analysis showed that acid deposition exerted a stronger impact on the variation of acid-extracted Ca and Mg in the surface sediment than the biomineralization in Taihu Lake. For the total Ca and Mg concentration in the spring, however, no significant change between the surface and deeper sediment in the northwest lake was observed, indicating that the carbonate precipitation via biomineralization and the carbonate dissolution due to acidic deposition were in a dynamic balance. These features are of major importance for the understanding of combined effects of acid deposition and eutrophication on freshwater lakes.

Study on of the current status of volatile organic compounds pollution in typical rural drinking water and the relationship between its concentration and health of the population,in Huai’an, Jiangsu / 中华流行病学杂志

Objective This study was to understand the status of pollution on drinking water, by volatile organic compounds(VOCs),among rural residents living in the basin of Huaihe River. Relationship between the morbidity,morbidity of cancers and VOCs were also explored. Methods 28 villages were chosen from Xuyi,Jinhu,Chuzhou along the Huaihe River,with water samples collected from ditch pond water,shallow wells,deep wells in November-December 2010. VOCs indicators were evaluated according to the Standard Quality GB 5749-2006 for Drinking Water. Results Methylene chloride,chloroform,benzene and carbon tetrachloride were all detected in 76 water samples. The rates of chloroform,benzene,carbon tetrachloride which exceeding the quality standards were 3.95%,21.05% and 22.37%,but no significant differences were found among these three water resources in chloroform,benzene or carbon tetrachloride. Results from the correlation analysis showed that benzene had positive correlation with tumor deaths(r=0.24,P<0.05). Results from the risk assessment on health showed that some chloroform,benzene,carbon tetrachloride products which were related to the risks of cancers were exceeding the acceptable ranges of risk,with the rates as 28.95%,22.37% and 64.47% but with no significant differences among the three water resources(P>0.05). Conclusion Drinking waters for rural residents along the Huaihe River were polluted while VOCs might have related to tumor incidence with potential impact and risk to the health of local residents.

Study on of the current status of volatile organic compounds pollution in typical rural drinking water and the relationship between its concentration and health of the population,in Huai’an, Jiangsu / 中华流行病学杂志

Objective This study was to understand the status of pollution on drinking water, by volatile organic compounds(VOCs),among rural residents living in the basin of Huaihe River. Relationship between the morbidity,morbidity of cancers and VOCs were also explored. Methods 28 villages were chosen from Xuyi,Jinhu,Chuzhou along the Huaihe River,with water samples collected from ditch pond water,shallow wells,deep wells in November-December 2010. VOCs indicators were evaluated according to the Standard Quality GB 5749-2006 for Drinking Water. Results Methylene chloride,chloroform,benzene and carbon tetrachloride were all detected in 76 water samples. The rates of chloroform,benzene,carbon tetrachloride which exceeding the quality standards were 3.95%,21.05% and 22.37%,but no significant differences were found among these three water resources in chloroform,benzene or carbon tetrachloride. Results from the correlation analysis showed that benzene had positive correlation with tumor deaths(r=0.24,P<0.05). Results from the risk assessment on health showed that some chloroform,benzene,carbon tetrachloride products which were related to the risks of cancers were exceeding the acceptable ranges of risk,with the rates as 28.95%,22.37% and 64.47% but with no significant differences among the three water resources(P>0.05). Conclusion Drinking waters for rural residents along the Huaihe River were polluted while VOCs might have related to tumor incidence with potential impact and risk to the health of local residents.

Study on of the current status of volatile organic compounds pollution in typical rural drinking water and the relationship between its concentration and health of the population, in Huai'an, Jiangsu / 中华流行病学杂志

<p><b>OBJECTIVE</b>This study was to understand the status of pollution on drinking water, by volatile organic compounds (VOCs), among rural residents living in the basin of Huaihe River. Relationship between the morbidity, morbidity of cancers and VOCs were also explored.</p><p><b>METHODS</b>28 villages were chosen from Xuyi,Jinhu, Chuzhou along the Huaihe River, with water samples collected from ditch pond water, shallow wells, deep wells in November-December 2010. VOCs indicators were evaluated according to the Standard Quality GB 5749-2006 for Drinking Water.</p><p><b>RESULTS</b>Methylene chloride, chloroform, benzene and carbon tetrachloride were all detected in 76 water samples. The rates of chloroform, benzene, carbon tetrachloride which exceeding the quality standards were 3.95% , 21.05% and 22.37% , but no significant differences were found among these three water resources in chloroform, benzene or carbon tetrachloride. Results from the correlation analysis showed that benzene had positive correlation with tumor deaths (r = 0.24, P < 0.05). Results from the risk assessment on health showed that some chloroform, benzene, carbon tetrachloride products which were related to the risks of cancers were exceeding the acceptable ranges of risk, with the rates as 28.95%, 22.37% and 64.47% but with no significant differences among the three water resources (P > 0.05).</p><p><b>CONCLUSION</b>Drinking waters for rural residents along the Huaihe River were polluted while VOCs might have related to tumor incidence with potential impact and risk to the health of local residents.</p>