State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Annis Water Resources Institute, Grand Valley State University, 740 West Shoreline Drive, Muskegon, MI, USA.
J Environ Sci (China). 2023 May;127:1-14. doi: 10.1016/j.jes.2022.03.043. Epub 2022 Apr 12.
Understanding the history of microcystins (MCs) pollution in large lakes can help inform future lake management. We collected sediment cores from Lake Taihu to: investigate the long-term record of MCs (MC-LR, MC-YR, and MC-RR), explore the main environmental drivers of MCs, and assess their public health and ecological risks. Results showed that MCs content in all cores increased over time. The core from north Taihu had the highest MC concentrations, with an average total MCs (sum of MC-LR, MC-YR, and MC-RR = TMCs) content of (74.31±328.55) ng/g. The core from eastern Taihu showed the lowest average TMCs content of (2.91±3.95) ng/g. PCA showed that sediment MCs at the three sites were positively correlated with sediment chlorophyll-a. MC-LR and MC-YR in northern and western Taihu negatively correlated with both the sediment total organic carbon/sediment total nitrogen ratio (STOC/STN) and water nitrate (NO-N) concentration, but three MC congeners at eastern Taihu showed positive correlations with water orthophosphate (PO-P), NO-N, and STOC/STN. Generalized additive model analysis at each site revealed that NO-N was the main TMCs driver in northern and western Taihu where phytoplankton dominated, whereas PO-P was the main TMCs driver in eastern Taihu where macrophytes dominated. At the whole lake scale, total phosphorus (TP) and PO-P were the most important environmental drivers influencing MCs; TP explained 47.4%, 44.2%, and 47.6% while orthophosphate explained 34.8%, 31.2%, and 34.7% of the deviance on TMCs, MC-LR, and MC-YR, respectively. NO-N also showed a strong effect on MCs variation, especially on MC-YR. Risk assessment showed that both ecological and public health risk has increased in recent years. We conclude that while control of phosphorus and nitrogen input should be a major focus for future lake management, lake zone-specific management strategies may also be important.
了解大型湖泊中微囊藻毒素（MCs）污染的历史可以为未来的湖泊管理提供信息。我们从太湖采集了沉积物岩芯，以：研究 MCs（MC-LR、MC-YR 和 MC-RR）的长期记录，探讨 MCs 的主要环境驱动因素，并评估其对公共健康和生态的风险。结果表明，所有岩芯中的 MCs 含量随时间增加。太湖北部岩芯的 MC 浓度最高，总 MCs（MC-LR、MC-YR 和 MC-RR 的总和）含量平均为（74.31±328.55）ng/g。太湖东部岩芯的平均总 MCs 含量最低，为（2.91±3.95）ng/g。PCA 表明，三个地点的沉积物 MCs 与沉积物叶绿素-a 呈正相关。太湖北部和西部的 MC-LR 和 MC-YR 与沉积物总有机碳/沉积物总氮比（STOC/STN）和水硝酸盐（NO-N）浓度呈负相关，但太湖东部的三种 MC 同系物与水正磷酸盐（PO-P）、NO-N 和 STOC/STN 呈正相关。每个地点的广义加性模型分析表明，在以浮游植物为主的太湖北部和西部，NO-N 是 TMCs 的主要驱动因素，而在以大型植物为主的太湖东部，PO-P 是 TMCs 的主要驱动因素。在整个湖泊范围内，总磷（TP）和 PO-P 是影响 MCs 的最重要环境驱动因素；TP 分别解释了 TMCs、MC-LR 和 MC-YR 变化的 47.4%、44.2%和 47.6%，而正磷酸盐解释了 34.8%、31.2%和 34.7%。NO-N 对 MCs 变化也有很强的影响，特别是对 MC-YR。风险评估表明，近年来生态和公共健康风险都有所增加。我们的结论是，尽管控制磷和氮的输入应该是未来湖泊管理的主要重点，但针对湖泊特定区域的管理策略也可能很重要。
