作　　者： ; ; ; ; ; ;

机构地区： 中南大学湘雅医学院生物科学与技术学院

出　　处： 《中国科学：生命科学》 2011年第8期669-677,共9页

摘　　要： 2010年9月下旬,湘江中下游发生藻类水华,严重影响了沿线居民的生活.采集湘江上游永州、中游衡阳与下游株洲、湘潭、长沙段水样,对此次水华期间浮游植物群落结构、优势种类进行了调查分析,并测定其对湘江金属离子的积累,进行小鼠生物毒性实验,旨在评价此类水华是否将对湘江水生生态系统及人体健康构成威胁.结果表明：（1）光学显微镜与扫描电子显微镜分析,此次水华为硅藻门颗粒浮生直链藻（Aulacoseira granulata）水华.湘潭和长沙段水华最为严重,藻细胞数均达到1.3×105丝状体/L,长沙段叶绿素a含量达0.04mg/L;（2）湘江颗粒浮生直链藻对金属离子Al,Fe和Mn富集量分别达到4.4×103,768.4和138.7mg/kg干重,富集系数分别为4.0×105,7.7×105和3.2×103;其对高毒重金属Pb富集量为19.2mg/kg干重,富集系数为9.6×103;（3）小鼠生物毒性实验证实,湘江重金属污染条件下颗粒浮生直链藻水华存在一定生物毒性,全组份组LD50为384mg/kg,95%可信限介于228.5~646.3mg/kg之间,对湘江水生生态系统及沿线居民健康造成了威胁. In the mid-late September 2010,algae bloomed in the mid/downstream of Xiangjiang River（Hunan,China）,one of the most heavily polluted rivers by heavy metals.Water supply in the downstream was seriously affected.The present study aims to identify the bloom-forming species,determine the bioaccumulation of heavy metals by the organism,and get knowledge about whether the algal bloom would endanger the water ecosystem and local human health.According to the observations under the light and scanning electronic microscope,the dominant species was identified to be Aulacoseira granulata,which was formerly known as Melosira granulata.Investigations at upstream Yongzhou,midstream Hengyang,downstream Zhuzhou,Xiangtan and Changsha sites suggested that the heaviest bloom occurred at Xiangtan and Changsha sites,where the number of A.granulata reached 1.3×105 filaments/L and chlorophyll a 0.04 mg/L.Concentrations of Al,Fe and Mn in the phytoplankton reached 4.4×103,768.4,138.7 mg/kg dry weight,with a bioaccumulation factor of 4.0×105,7.7×105,3.2×103,respectively.The element Pb showed the highest level of bioaccumulation among highly toxic heavy metals,with a concentration of 19.2 mg/kg dry weight and bioaccumulation factor value 9.6×103.The mouse assay tested with the full component of phytoplankton suggested the bloom was toxic.It has a LD50 value of 384 mg/kg and all the surviving mice did not recover to the initial weight at 72 h.According to the results,the A.granulata bloom formed in the heavy metals polluted river posed a threat to the water ecosystem and local human health.Intensive measures should be taken to control the eutrophication and heavy metal pollution in the river.

关 键 词： 硅藻 颗粒浮生直链藻 生物富集 湘江水华 重金属

领　　域： [环境科学与工程]