Temporal and spatial changes of total nitrogen （TN）, total phosphorus （TP） and chlorophyll-a （Chl-a） in a shallow lake, Lake Chaohu, China, were investigated using monthly monitoring data from 2001 through 2011....Temporal and spatial changes of total nitrogen （TN）, total phosphorus （TP） and chlorophyll-a （Chl-a） in a shallow lake, Lake Chaohu, China, were investigated using monthly monitoring data from 2001 through 2011. The results showed that the annual mean concentration ranges of TN, TP, and Chl-a were 0.08-14.60 mg/L, 0.02-1.08 mg/L, and 0.10-465.90 ~tg/L, respectively. Our data showed that Lake Chaohu was highly eutrophic and that water quality showed no substantial improvement during 2001 through 2011. The mean concentrations of TP, TN and Chl-a in the western lake were significantly higher than in the eastern lake, which indicates a spatial distribution of the three water parameters. The annual mean ratio of TN：TP by weight ranged from 10 to 20, indicating that phosphorus was the limiting nutrient in this lake. A similar seasonality variation for TP and Chl-a was observed. Riverine TP and NH4＋ loading from eight major tributaries were in the range of 1.56× 10^4-5.47 × 10^4 and 0.19 × 104-0.51 × 10^4 tons/yr over 2002-2011, respectively, and exceeded the water environmental capability of the two nutrients in the lake by a factor of 3-6. Thus reduction of nutrient loading in the sub-watershed and tributaries would be essential for the restoration of Lake Chaohu.展开更多
As the largest contributor to water impairment, agriculture-related pollution has attracted the attention of scientists as well as policy makers, and quantitative information is being sought to focus and advance the p...As the largest contributor to water impairment, agriculture-related pollution has attracted the attention of scientists as well as policy makers, and quantitative information is being sought to focus and advance the policy debate. This study applies the panel unit root, heterogeneous panel cointegration, and panel-based dynamic ordinary least squares to investigate the Environ- mental Kuznets Curve on environmental issues resulting from use of agricultural synthetic fertilizer, pesticide, and film for 31 provincial economies in China's Mainland from 1989 to 2009. The empirical results indicate a positive long-ran co-integrated relationship between the environ- mental index and real GDP per capita. This relationship takes on the inverted U-shaped Environmental Kuznets Curve, and the value of the turning point is approximately 10,000-13,000, 85,000-89,000 and over 160,000 CNY, for synthetic fertilizer nitrogen indicator, fertilizer phos- phorus indicator and pesticide indicator, respectively. At present, China is subject to tremendous environmental pressure and should assign more importance to special agriculture-related environmental issues.展开更多
基金supported by the National Science-technology Support Project of China (No.2010BAC69B02)the National Natural Science Foundation of China (No. 41203080)
文摘Temporal and spatial changes of total nitrogen （TN）, total phosphorus （TP） and chlorophyll-a （Chl-a） in a shallow lake, Lake Chaohu, China, were investigated using monthly monitoring data from 2001 through 2011. The results showed that the annual mean concentration ranges of TN, TP, and Chl-a were 0.08-14.60 mg/L, 0.02-1.08 mg/L, and 0.10-465.90 ~tg/L, respectively. Our data showed that Lake Chaohu was highly eutrophic and that water quality showed no substantial improvement during 2001 through 2011. The mean concentrations of TP, TN and Chl-a in the western lake were significantly higher than in the eastern lake, which indicates a spatial distribution of the three water parameters. The annual mean ratio of TN：TP by weight ranged from 10 to 20, indicating that phosphorus was the limiting nutrient in this lake. A similar seasonality variation for TP and Chl-a was observed. Riverine TP and NH4＋ loading from eight major tributaries were in the range of 1.56× 10^4-5.47 × 10^4 and 0.19 × 104-0.51 × 10^4 tons/yr over 2002-2011, respectively, and exceeded the water environmental capability of the two nutrients in the lake by a factor of 3-6. Thus reduction of nutrient loading in the sub-watershed and tributaries would be essential for the restoration of Lake Chaohu.
基金This study was supported by the State Basic Science Key Project of China （No. 2007FY110300）, the National Natural Science Foundation of China （Grant Nos. 41271556 and 41301642）, China Postdoctoral Science Foundation Funded Project （No. 2013M541026）, and the Go｜da Meir Fellowship. This paper was finally finished while the first author was a Fellow at the Department of Geography, The Hebrew University of Jerusalem. The authors would like to appreciate Professor Eran Feitelson and Ms Rachel Friedman for their guidance and comments.
文摘As the largest contributor to water impairment, agriculture-related pollution has attracted the attention of scientists as well as policy makers, and quantitative information is being sought to focus and advance the policy debate. This study applies the panel unit root, heterogeneous panel cointegration, and panel-based dynamic ordinary least squares to investigate the Environ- mental Kuznets Curve on environmental issues resulting from use of agricultural synthetic fertilizer, pesticide, and film for 31 provincial economies in China's Mainland from 1989 to 2009. The empirical results indicate a positive long-ran co-integrated relationship between the environ- mental index and real GDP per capita. This relationship takes on the inverted U-shaped Environmental Kuznets Curve, and the value of the turning point is approximately 10,000-13,000, 85,000-89,000 and over 160,000 CNY, for synthetic fertilizer nitrogen indicator, fertilizer phos- phorus indicator and pesticide indicator, respectively. At present, China is subject to tremendous environmental pressure and should assign more importance to special agriculture-related environmental issues.
