To assess the contamination trends and potential bio-availability of sediment-bound heavy metals,concentrations of heavy metals in acid-leaching fraction and in bulk sediments from the two typical bays(the Meiliang Ba...To assess the contamination trends and potential bio-availability of sediment-bound heavy metals,concentrations of heavy metals in acid-leaching fraction and in bulk sediments from the two typical bays(the Meiliang Bay and Xuhu Bay) of the Taihu Lake,East China,were studied.Pb and Zn showed elevated concentrations in the sediments from both areas,although sedimentation history and degree of pollution are different between the two bays.In the Meiliang Bay,both Pb and Zn pollutions started in the late 1970's,the same time as the beginning of eutrophication of the lake,while the in the Xuhu Bay the metal contamination started since recent 10 years.The concentrations of acid-leachable Pb in the sediments from the Meiliang Bay are correlated with the historical eutrophication process.Before the eutrophication and heavy metal pollution,the chemical properties of the lake sediments were the same as the source compositions of the Xiashu loess.Both Pb and Zn in the sediments mainly occur in leachable forms by nitric or hydrochloric acid,whilst most of Cu is in residual fraction.The results indicate that both Pb and Zn may have higher mobility and bioavailability in water and biology than Cu.展开更多
The species of Cu, Pb, Zn, Cd and Cr in sediments of the Taihu Lake, China, have been analyzed using the sequential chemical extraction method. Variations in the chemical fractions of these metals and their geographic...The species of Cu, Pb, Zn, Cd and Cr in sediments of the Taihu Lake, China, have been analyzed using the sequential chemical extraction method. Variations in the chemical fractions of these metals and their geographic distributions have also been studied. For all five metals, the residual fraction is highest but the exchangeable fraction is lowest among all the fractions. Compared to other metals, Cd has the highest percentage in the exchangeable fraction, and Cr is associated mainly with the residual fraction. Cu in the organic fraction and Pb in the Fe-Mn fraction are the important species, whereas the lowest percentages are found for Cd in the organic fraction, Cu in the Fe-Mn oxide fraction and Pb in the carbonate fraction. With respect to spatial differences, the total contents in the non-residual fractions of the metals in bay sediments are found to be higher than those in other sediments. The fractions of Cd, Cu and Cr showed significant variations in different regions. The fractions of Pb and Zn, however, did not show significant variations in spatial distribution, suggesting different amounts and different paths of anthropogenic input for the metals. Comparisons of the metal speciation indicated that Cd might be the most bioavailable metal, followed by Pb.展开更多
Among the Chinese lakes with the problem of eutrophication, the Taihu Lake, the Chaohu Lake and the Dianchi Lake have the worst cases of blue algae outbreak, which happen every year. Other lakes also have problems of ...Among the Chinese lakes with the problem of eutrophication, the Taihu Lake, the Chaohu Lake and the Dianchi Lake have the worst cases of blue algae outbreak, which happen every year. Other lakes also have problems of blue algae outbreak at various degrees. However, some lakes don't have such problems. Practices have shown that through comprehensive management, the problem can be basically eliminated or significantly alleviated. "Water bloom" and blue algae outbreak have different connotation. The major factors affecting blue algae outbreak are sources of pollutants and ecological environment. Experiences are summed up and a new thinking on its management is developed: resolving the problem of blue algae is fundamental to lake management and development goals should be clearly set forth so as to eventually build a healthy aquatic ecosys- tem. The problem of blue algae can't be fully tackled by solely relying on the management of eutrophication but only by combining efforts of reducing the amount of blue algae and the management of eutrophication. The number of reduced blue algae should be larger than that of naturally prolifera- ted algae so as to alleviate and eliminate the problem of blue algae outbreak. Various engineering and technical measures and relevant protective procedures should be carried out in a scientific and proper manner. The total amount of nitrogen and phosphorous entering the lake either from point-source or non-point source pollution should be substantially reduced. Controlling the source of pollution and intercepting pollutants are the bas- ic measures. Wastewater treatment plant is the largest point source pollution in the future and adequate plants should be built with improved emission standards. Meanwhile, other measures including fishing out blue algae, diverting water, dredging, ecological restoration and expanding reed zone, should be implemented to alleviate the problem of eutrophication and eventually eliminate the problem of blue algae outbreak.展开更多
[ Objective] The study aimed to analyze the pollution sources and degree of sediments in seven northwestern rivers flowing into Taihu Lake. [ Method] Based on a survey for the sediments in seven rivers flowing into th...[ Objective] The study aimed to analyze the pollution sources and degree of sediments in seven northwestern rivers flowing into Taihu Lake. [ Method] Based on a survey for the sediments in seven rivers flowing into the northwestern Taihu Lake from 2005 to 2007, the molar ratio of major elements was used to determine the main pollution sources of each channel, and the heavy metal pollution of sediments in the seven rivers was assessed by enrichment coefficient. [ Result] Mashan River, Liangxi River and Xiwan River mainly suffered municipal pollution; Zhihu Port and Caoqiao River were chiefly subjected to industrial pollution; Dapu River and Wujin River were mainly affected by agricultural pollution. In addition, the rivers mainly suffering industrial pollution had the most serious heavy metal pollution, followed by the rivers mainly undergoing agricultural pollu- tion, while the rivers chiefly affected by municipal pollution had the minimum pollution. [ Conclusion] The research could provide scientific references for the control of river pollution by heavy metals along Taihu Lake basin.展开更多
The relationship between body size and stable isotopic signatures of the omnivorous Redfin Culter(C ultrichthys erythropterus),commonly found in East Lake Taihu,was investigated. Previous analyses of C. erythropterus ...The relationship between body size and stable isotopic signatures of the omnivorous Redfin Culter(C ultrichthys erythropterus),commonly found in East Lake Taihu,was investigated. Previous analyses of C. erythropterus stomach contents have shown that this species undergoes a diet switch from being predominantly zooplanktivorous to piscivorous during its life history. This was confirmed by stable carbon isotopic signature(δ 13 C) in this study,in which δ 13 C was positively correlated with both standard length and weight. The importance of littoral-benthic resources in supporting C. erythropterus during its lifespan was also demonstrated using a two-source mixing model,the results of which showed a significant increasing trend in the contribution of littoral-benthic energy. However,the stable nitrogen isotopic signature(δ 15N) exhibited an unusual pattern compared with previous studies. The δ 15 N of C. erythropterus showed no relationship with body size,even though dietary changes were observed. This indicated that δ 15 N alone cannot fully reflect a diet shift in a species and possible variability in isotopic signatures over its life history. This should be considered when using stable isotopic signatures to investigate intra-specific variations and the timing of life-history events,such as estimating the trophic positions of fish species.展开更多
基金supported by 973 Project on the Processes of Lake Eutrophication and the Mechanism of Cyanobacterial Blooming (2002CB412300)National Survey of Land and Source (200420130002)
文摘To assess the contamination trends and potential bio-availability of sediment-bound heavy metals,concentrations of heavy metals in acid-leaching fraction and in bulk sediments from the two typical bays(the Meiliang Bay and Xuhu Bay) of the Taihu Lake,East China,were studied.Pb and Zn showed elevated concentrations in the sediments from both areas,although sedimentation history and degree of pollution are different between the two bays.In the Meiliang Bay,both Pb and Zn pollutions started in the late 1970's,the same time as the beginning of eutrophication of the lake,while the in the Xuhu Bay the metal contamination started since recent 10 years.The concentrations of acid-leachable Pb in the sediments from the Meiliang Bay are correlated with the historical eutrophication process.Before the eutrophication and heavy metal pollution,the chemical properties of the lake sediments were the same as the source compositions of the Xiashu loess.Both Pb and Zn in the sediments mainly occur in leachable forms by nitric or hydrochloric acid,whilst most of Cu is in residual fraction.The results indicate that both Pb and Zn may have higher mobility and bioavailability in water and biology than Cu.
文摘The species of Cu, Pb, Zn, Cd and Cr in sediments of the Taihu Lake, China, have been analyzed using the sequential chemical extraction method. Variations in the chemical fractions of these metals and their geographic distributions have also been studied. For all five metals, the residual fraction is highest but the exchangeable fraction is lowest among all the fractions. Compared to other metals, Cd has the highest percentage in the exchangeable fraction, and Cr is associated mainly with the residual fraction. Cu in the organic fraction and Pb in the Fe-Mn fraction are the important species, whereas the lowest percentages are found for Cd in the organic fraction, Cu in the Fe-Mn oxide fraction and Pb in the carbonate fraction. With respect to spatial differences, the total contents in the non-residual fractions of the metals in bay sediments are found to be higher than those in other sediments. The fractions of Cd, Cu and Cr showed significant variations in different regions. The fractions of Pb and Zn, however, did not show significant variations in spatial distribution, suggesting different amounts and different paths of anthropogenic input for the metals. Comparisons of the metal speciation indicated that Cd might be the most bioavailable metal, followed by Pb.
文摘Among the Chinese lakes with the problem of eutrophication, the Taihu Lake, the Chaohu Lake and the Dianchi Lake have the worst cases of blue algae outbreak, which happen every year. Other lakes also have problems of blue algae outbreak at various degrees. However, some lakes don't have such problems. Practices have shown that through comprehensive management, the problem can be basically eliminated or significantly alleviated. "Water bloom" and blue algae outbreak have different connotation. The major factors affecting blue algae outbreak are sources of pollutants and ecological environment. Experiences are summed up and a new thinking on its management is developed: resolving the problem of blue algae is fundamental to lake management and development goals should be clearly set forth so as to eventually build a healthy aquatic ecosys- tem. The problem of blue algae can't be fully tackled by solely relying on the management of eutrophication but only by combining efforts of reducing the amount of blue algae and the management of eutrophication. The number of reduced blue algae should be larger than that of naturally prolifera- ted algae so as to alleviate and eliminate the problem of blue algae outbreak. Various engineering and technical measures and relevant protective procedures should be carried out in a scientific and proper manner. The total amount of nitrogen and phosphorous entering the lake either from point-source or non-point source pollution should be substantially reduced. Controlling the source of pollution and intercepting pollutants are the bas- ic measures. Wastewater treatment plant is the largest point source pollution in the future and adequate plants should be built with improved emission standards. Meanwhile, other measures including fishing out blue algae, diverting water, dredging, ecological restoration and expanding reed zone, should be implemented to alleviate the problem of eutrophication and eventually eliminate the problem of blue algae outbreak.
文摘[ Objective] The study aimed to analyze the pollution sources and degree of sediments in seven northwestern rivers flowing into Taihu Lake. [ Method] Based on a survey for the sediments in seven rivers flowing into the northwestern Taihu Lake from 2005 to 2007, the molar ratio of major elements was used to determine the main pollution sources of each channel, and the heavy metal pollution of sediments in the seven rivers was assessed by enrichment coefficient. [ Result] Mashan River, Liangxi River and Xiwan River mainly suffered municipal pollution; Zhihu Port and Caoqiao River were chiefly subjected to industrial pollution; Dapu River and Wujin River were mainly affected by agricultural pollution. In addition, the rivers mainly suffering industrial pollution had the most serious heavy metal pollution, followed by the rivers mainly undergoing agricultural pollu- tion, while the rivers chiefly affected by municipal pollution had the minimum pollution. [ Conclusion] The research could provide scientific references for the control of river pollution by heavy metals along Taihu Lake basin.
基金Supported by the National Natural Science Foundation of China(No.41206124)the Ph.D Programs Foundation of Ministry of Education of China(No.23104120001)the "Chen Guang" Project(No.10CG52)
文摘The relationship between body size and stable isotopic signatures of the omnivorous Redfin Culter(C ultrichthys erythropterus),commonly found in East Lake Taihu,was investigated. Previous analyses of C. erythropterus stomach contents have shown that this species undergoes a diet switch from being predominantly zooplanktivorous to piscivorous during its life history. This was confirmed by stable carbon isotopic signature(δ 13 C) in this study,in which δ 13 C was positively correlated with both standard length and weight. The importance of littoral-benthic resources in supporting C. erythropterus during its lifespan was also demonstrated using a two-source mixing model,the results of which showed a significant increasing trend in the contribution of littoral-benthic energy. However,the stable nitrogen isotopic signature(δ 15N) exhibited an unusual pattern compared with previous studies. The δ 15 N of C. erythropterus showed no relationship with body size,even though dietary changes were observed. This indicated that δ 15 N alone cannot fully reflect a diet shift in a species and possible variability in isotopic signatures over its life history. This should be considered when using stable isotopic signatures to investigate intra-specific variations and the timing of life-history events,such as estimating the trophic positions of fish species.