Characteristics of the phytoplankton community and bioaccumulation of heavy metals during algal blooms in Xiangjiang River (Hunan,China)  

作　　者：LI Jie PENG FuLi DING DongBo ZHANG ShuBing LI DeLiang ZHANG Ting 

机构地区：[1]School of Biological Science and Technology, Central South University, Changsha 410013, China [2]Department of Ecology, China National Environmental Monitoring Centre, Beijing 100012, China [3]College of Animal Science and Technology, Hunan Agriculture University, Changsha 410128, China

出　　处：《Science China(Life Sciences)》2011年第10期931-938,共8页中国科学（生命科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos.31000179 and 31000183)

摘　　要：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.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 of A.granulata peaked at 1.3×10 5 filaments L 1 and chlorophyll a at 0.04 mg L 1.Concentrations of Al,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 LD 50 was 384 mg kg 1 and all surviving mice lost weight during the first 72 h after exposure.Our results demonstrate that blooms of A.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.

关 键 词：Aulacoseira granulata BIOACCUMULATION diatom bloom heavy metal Xiangjiang River 

分 类 号：X503.2[环境科学与工程—环境工程] TV697.25[水利工程—水利水电工程]