Samples were collected from two core sediments(C1 and C2) of Xiangjiang River,Chang-Zhu-Tan region,Hunan Province,China.The heavy metal contents are relatively higher,especially for the surface or near the surface lay...Samples were collected from two core sediments(C1 and C2) of Xiangjiang River,Chang-Zhu-Tan region,Hunan Province,China.The heavy metal contents are relatively higher,especially for the surface or near the surface layers.The calculated anthropogenic factor values indicate that all the heavy metals except for Cr in the core samples are enriched,especially for Cd,with the maximum enriching coefficients of 119.44,and 84.67 in C1 and C2,respectively.The correlation of heavy metals with sulphur indicates that they are precipitated as metal sulphides.Correlation matrix shows significant association between heavy metals and mud.Factor analysis identifies that signified anthropogenic activities affect the region of Xiangjiang River.展开更多
The frequency of algal blooms has increased in the mid and downstream reaches of the Xiangjiang River （Hunan, China）, one of the most heavily polluted rivers in China. We identified the bloom-forming species in a bl...The frequency of algal blooms has increased in the mid and downstream reaches of the Xiangjiang River （Hunan, China）, one of the most heavily polluted rivers in China. We identified the bloom-forming species in a bloom that occurred mid-late September 2010. In addition, we determined the extent of metal bioaccumulation in the algae and measured the toxicity of the algae using a mouse bioassay. Water samples were collected at upstream （Yongzhou）, midstream （Hengyang）, and downstream （Zhuzhou, Xiangtan, and Changsha） sites. The dominant species was Aulacoseira granulata, formerly known as Melosira granulata. The heaviest bloom occurred at Xiangtan and Changsha, where the number ofA. granulata peaked at 1.3×10^5 filaments L-1 and chlorophyll a at 0.04 mg L-1. Concentrations of A1, Fe, and Mn were 4.4×10^3, 768.4, and 138.7 mg kg-1 dry weight in the phytoplankton. The bioaccumulation factor was 4.0×10^5, 7.7×10^5, and 3.2×10^3, respectively. The heavy metal Pb had the greatest tendency to bioaccumulate among the highly toxic heavy metals, with a concentration of 19.2 mg kg-1 dry weight and bioaccumulation factor of 9.6×10^3. The mouse bioassay suggested the bloom was toxic. The LD50 was 384 mg kg-1 and all surviving mice lost weight during the first 72 h after exposure. Our results demonstrate that blooms ofA. granulata in rivers contaminated with heavy metals pose a threat to freshwater ecosystems and human health. Thus, measures should be taken to control eutrophication and heavy metal pollution in such rivers.展开更多
基金Project(1212010) supported by the China Geological Survey for Ecosystem Geochemistry Assessment in City of Changsha,Zhuzhou and Xiangtan
文摘Samples were collected from two core sediments(C1 and C2) of Xiangjiang River,Chang-Zhu-Tan region,Hunan Province,China.The heavy metal contents are relatively higher,especially for the surface or near the surface layers.The calculated anthropogenic factor values indicate that all the heavy metals except for Cr in the core samples are enriched,especially for Cd,with the maximum enriching coefficients of 119.44,and 84.67 in C1 and C2,respectively.The correlation of heavy metals with sulphur indicates that they are precipitated as metal sulphides.Correlation matrix shows significant association between heavy metals and mud.Factor analysis identifies that signified anthropogenic activities affect the region of Xiangjiang River.
基金supported by the National Natural Science Foundation of China (Grant Nos.31000179 and 31000183)
文摘The frequency of algal blooms has increased in the mid and downstream reaches of the Xiangjiang River （Hunan, China）, one of the most heavily polluted rivers in China. We identified the bloom-forming species in a bloom that occurred mid-late September 2010. In addition, we determined the extent of metal bioaccumulation in the algae and measured the toxicity of the algae using a mouse bioassay. Water samples were collected at upstream （Yongzhou）, midstream （Hengyang）, and downstream （Zhuzhou, Xiangtan, and Changsha） sites. The dominant species was Aulacoseira granulata, formerly known as Melosira granulata. The heaviest bloom occurred at Xiangtan and Changsha, where the number ofA. granulata peaked at 1.3×10^5 filaments L-1 and chlorophyll a at 0.04 mg L-1. Concentrations of A1, Fe, and Mn were 4.4×10^3, 768.4, and 138.7 mg kg-1 dry weight in the phytoplankton. The bioaccumulation factor was 4.0×10^5, 7.7×10^5, and 3.2×10^3, respectively. The heavy metal Pb had the greatest tendency to bioaccumulate among the highly toxic heavy metals, with a concentration of 19.2 mg kg-1 dry weight and bioaccumulation factor of 9.6×10^3. The mouse bioassay suggested the bloom was toxic. The LD50 was 384 mg kg-1 and all surviving mice lost weight during the first 72 h after exposure. Our results demonstrate that blooms ofA. granulata in rivers contaminated with heavy metals pose a threat to freshwater ecosystems and human health. Thus, measures should be taken to control eutrophication and heavy metal pollution in such rivers.
