中文摘要：

以探讨叶绿素a(Chl-a)阈值为主要目的于2013年6~10月间每月在太湖采样,通过固相萃取超高效液相色谱串联质谱法对水体中3种微囊藻毒素(MC-LR、MC-RR、MC-YR)进行检测.利用SPSS软件分析各种形态的微囊藻毒素(MCs)与总氮(TN)、总磷(TP)、Chl-a、高锰酸盐指数等富营养指标的相关性,分析了MC-LR、MCs与Chl-a的关系.结果表明,太湖MCs污染较严重,其浓度的空间分布特征为:梅梁湾】贡湖、西部沿岸区】湖心区】胥湖区、南部湖区,并以MC-LR浓度最高;相关性分析表明MC-LR、MC-RR、MC-YR及MCs均与高锰酸盐指数、TN、TP、Chl-a呈极显著正相关(P【0.01).结合饮用水中MC-LR和MCs的标准限值分析得出,太湖Chl-a的阈值是12.26 mg·m-3,与美国北卡罗莱纳州湖泊的Chl-a标准值比较属于安全阈值,具有一定的科学性.

英文摘要：

Water samples were collected in Lake Taihu from June to October in 2013 in order to investigate the threshold of chlorophyll a (Chl-a). The concentrations of three microcystins isomers ( MC-LR, MC-RR, MC-YR) were detected by means of solid phase extraction and high performance liquid chromatography-tandem mass spectrometry. The correlations between various MCs and eutrophication factors, for instance of total nitrogen ( TN), total phosphorus ( TP), chlorophyll a, permanganate index etc were analyzed. The threshold of Chl-a was studied based on the relationships between MC-LR, MCs and Chl-a. The results showed that Lake Taihu was severely polluted by MCs and its spatial distribution could be described as follows: the concentration in Meiliang Bay was the highest, followed by Gonghu Bay and Western Lake, and Lake Center; the least polluted areas were in Lake Xuhu and Southern Lake. The concentration of MC-LR was the highest among the 3 MCs. The correlation analysis indicated that MC-LR, MC-RR, MC-YR and MCs had very positive correlation with permanganate index, TN, TP and Chl-a (P < 0. 01). The threshold value of Chl-a was 12. 26 mg·m - 3 according to the standard thresholds of MC-LR and MCs in drinking water. The threshold value of Chl-a in Lake Taihu was very close to the standard in the State of North Carolina, which demonstrated that the threshold value provided in this study was reasonable.