Yuan Li-Juan, Liao Qie-Gen, Zhang Li, Zhang Da-Wen, Luo Lin-Guang, Liu Ju-Tao
Institute for Quality & Safety and Standards of Agricultural Products Research, Jiangxi Academy of Agricultural Sciences, Nanchang 330200, China.
Jiangxi Provincial Institute of Water Sciences, Nanchang 330029, China.
Huan Jing Ke Xue. 2018 Jan 8;39(1):450-459. doi: 10.13227/j.hjkx.201708227.
Poyang Lake is the largest freshwater lake in China and an important drinking water source for Jiangxi Province. Since the year 2000, toxic cyanobacteria have been observed frequently in Poyang Lake. In this study, water samples were collected in the lake quarterly (April 2012, August 2012, October 2012, and January 2013) to examine the spatial and seasonal variations in the concentrations of microcystins (MCs; MC-RR, -YR, and -LR) and their relationships with physiochemical and biological factors. MCs were determined by ultra-high-performance liquid chromatography-electrospray ionization tandem triple quadrupole/mass spectrometry (UPLC-MS/MS). MC-RR (accounting for 75.01% and 71.34% of intracellular MC (IMC) and extracellular MC (EMC) concentrations, respectively) was the most dominant variant in Poyang Lake, followed by MC-LR (accounting for 21.95% and 24.97% of IMC and EMC concentrations, respectively), while MC-YR was detected in low concentrations (accounting for 3.01% and 3.69% of IMC and EMC concentrations, respectively). Total MC concentrations (IMC + EMC, TMC) ranged from 0.49 to 3517.85 ng·L, with an average of 337.43 ng·L and only 2.53% (2 out of 79 water samples) of the water samples contained MCs concentrations exceeding the drinking water guideline level of 1 ng·L for MC-LR proposed by World Health Organization (WHO). IMC concentrations showed significant relationships with biomass (=0.47, <0.01), biomass (=0.68, <0.01), biomass (=0.56, <0.01), and Chl-a (=0.28, <0.01), but no significant correlation was found between intracellular MC concentration and biomass (>0.05), suggesting that and might be the main MCs-producing cyanobacteria in Poyang Lake. In addition, IMC concentrations were positively correlated with water temperature (=0.51, <0.01), transparence (=0.69, <0.01), Fe (=0.43, <0.01), and Zn contents (=0.43, <0.01), and negatively correlated with TN (=-0.44, <0.01), TP (=-0.29, <0.01), NH-N (=-0.33, <0.05), NO-N (=-0.28, <0.05), Ca (=-0.34, <0.01), and Mg(=-0.35, <0.05), while no significant correlations were observed between IMC concentrations and pH, PO-P, NO-N, electrical conductivity, permanganate index, and Cu content (>0.05). These results indicated that light intensity (represented by transparence), nitrogen, phosphorus, and water temperature might be the regulating factors of MCs production in Poyang Lake and trace elements (Fe, Zn, Ca, and Mg) can influence the MC production to a certain extent. IMCs and EMCs exhibited similar seasonal variations in Poyang Lake. The highest values of IMCs (531.87 ng·L) and EMCs (232.44 ng·L) were observed in summer. The concentrations of IMCs and EMCs in autumn were 31.97 ng·L and 6.49 ng·L, respectively. Low concentrations were observed in spring (0.55 ng·L and 0.88 ng·L of IMCs and EMCs, respectively) and winter (0.69 ng·L and 4.14 ng·L of IMCs and EMCs, respectively). The highest IMCs and EMCs values of Poyang Lake in summer were 2298.08 ng·L and 1219.77 ng·L, respectively, and the lowest values were 92.53 ng·L and 38.80 ng·L, respectively. Overall, the concentrations of IMCs in eastern bays, the vicinity of Songmen Mountain, Banghu Lake, and its outlet were higher than those in other regions. However, the spatial distributions of EMCs in Poyang Lake were different from those of IMCs. EMCs concentrations in the vicinity of Songmen Mountain, Banghu Lake, and its outlet were higher than those in other regions.
鄱阳湖是中国最大的淡水湖，也是江西省重要的饮用水源。自2000年以来，鄱阳湖频繁观测到有毒蓝藻。本研究于2012年4月、2012年8月、2012年10月和2013年1月每季度采集一次湖水样本，以研究微囊藻毒素（MCs；MC-RR、-YR和-LR）浓度的空间和季节变化及其与理化和生物因子的关系。采用超高效液相色谱-电喷雾电离串联三重四极杆/质谱（UPLC-MS/MS）测定MCs。MC-RR（分别占细胞内MC（IMC）和细胞外MC（EMC）浓度的75.01%和71.34%）是鄱阳湖最主要的变体，其次是MC-LR（分别占IMC和EMC浓度的21.95%和24.97%），而MC-YR的检测浓度较低（分别占IMC和EMC浓度的3.01%和3.69%）。总MC浓度（IMC + EMC，TMC）范围为0.49至3517.85 ng·L，平均为337.43 ng·L，仅2.53%（79个水样中有2个）的水样中MCs浓度超过世界卫生组织（WHO）提出的MC-LR饮用水指导水平1 ng·L。IMC浓度与生物量（r = 0.47，P < 0.01）、生物量（r = 0.68，P < 0.01）、生物量（r = 0.56，P < 0.01）和叶绿素a（r = 0.28，P < 0.01）呈显著相关，但细胞内MC浓度与生物量之间未发现显著相关性（P > 0.05），这表明 和 可能是鄱阳湖主要的产MCs蓝藻。此外，IMC浓度与水温（r = 0.51，P < 0.01）、透明度（r = 0.69，P < 0.01）、铁（r = 0.43，P < 0.01）和锌含量（r = 0.43，P < 0.01）呈正相关，与总氮（r = -0.44，P < 0.01）、总磷（r = -0.29，P < 0.01）、氨氮（r = -0.33，P < 0.05）、硝态氮（r = -0.28，P < 0.05）、钙（r = -0.34，P < 0.01）和镁（r = -0.35，P < 0.05）呈负相关，而IMC浓度与pH、磷酸根磷、亚硝态氮、电导率、高锰酸盐指数和铜含量之间未观察到显著相关性（P > 0.05）。这些结果表明，光照强度（以透明度表示）、氮、磷和水温可能是鄱阳湖MCs产生量的调节因子，微量元素（铁、锌、钙和镁）可在一定程度上影响MCs的产生。鄱阳湖的IMCs和EMCs表现出相似的季节变化。夏季观测到IMCs的最高值（531.87 ng·L）和EMCs的最高值（232.44 ng·L）。秋季IMCs和EMCs的浓度分别为31.97 ng·L和6.49 ng·L。春季（IMCs和EMCs分别为0.55 ng·L和0.88 ng·L）和冬季（IMCs和EMCs分别为0.69 ng·L和4.14 ng·L）观测到较低浓度。鄱阳湖夏季IMCs和EMCs的最高值分别为2298.08 ng·L和1219.77 ng·L，最低值分别为92.53 ng·L和38.80 ng·L。总体而言，东部湖湾、松门山附近、蚌湖及其出水口的IMCs浓度高于其他地区。然而，鄱阳湖EMCs的空间分布与IMCs不同。松门山附近、蚌湖及其出水口的EMCs浓度高于其他地区。
