Lance Emilie, Lepoutre Alexandra, Brient Luc, Maurin Nicolas, Guillon Emmanuel, Geffard Alain, Amon-Moreau Dominique
UMR-I 02 INERIS-URCA-ULH Stress Environnementaux et Biosurveillance des Milieux Aquatiques, Bâtiment 18, BP 1039, 51687 Reims CEDEX 2, France.
UMR ECOBIO, Université de Rennes 1, 35042 Rennes CEDEX, France.
Toxins (Basel). 2025 May 15;17(5):245. doi: 10.3390/toxins17050245.
Microcystins (MCs), hepatotoxins produced by cyanobacteria, represent a potential threat to aquatic ecosystems and human health. Measuring various environmental and cyanobacterial parameters in water samples can be useful for monitoring water quality and assessing risk but remains a short-term approach. Beyond local risk assessments, estimating global and medium-term levels of freshwater contamination by MC-producing cyanobacteria is challenging in large lakes due to the spatio-temporal variability of their proliferation and the need to multiply sampling dates and locations. In such conditions, a sentinel organism can be valuable for monitoring MCs in situ and providing a time-integrated picture of contamination levels at various stations. We previously assessed the ability of the freshwater bivalves and to act as biointegrators of MCs, even under low exposure levels to cyanobacteria. In this study, through a two-season investigation in several French lakes experiencing moderate cyanobacterial blooms, we evaluated the relevance of various parameters (cyanobacterial density and biovolume, chlorophyll-a, and phycocyanin) as well as the use of bivalves as indicators of medium-term freshwater contamination by MC-producing cyanobacteria. MC concentrations in cyanobacterial biomass (intracellular MCs) and in bivalves (free MCs, being unbound, and total free and protein-bound accumulated MCs) were measured alongside the characterization of phytoplankton communities. Both mussels integrated and highlighted the presence of intracellular MCs in the environment over the period between two successive water samplings, even at low contamination levels, demonstrating their suitability for in situ biomonitoring of MC-producing cyanobacteria. The results are discussed in terms of the strengths and limitations of different parameters for assessing MC contamination levels in waters depending on the objective (managing, preventing, or global evaluation) and the monitoring strategies used.
微囊藻毒素（MCs）是蓝藻产生的肝毒素，对水生生态系统和人类健康构成潜在威胁。测量水样中的各种环境和蓝藻参数有助于监测水质和评估风险，但这仍是一种短期方法。除了局部风险评估外，由于产生微囊藻毒素的蓝藻繁殖具有时空变异性，且需要增加采样日期和地点，因此在大型湖泊中估计其对淡水的全球和中期污染水平具有挑战性。在这种情况下，一种指示生物对于原位监测微囊藻毒素以及提供各监测点污染水平的时间积分情况可能很有价值。我们之前评估了淡水双壳贝类充当微囊藻毒素生物整合体的能力，即使在低水平接触蓝藻的情况下也是如此。在本研究中，通过对法国几个经历中度蓝藻水华的湖泊进行两季调查，我们评估了各种参数（蓝藻密度和生物量、叶绿素a和藻蓝蛋白）的相关性，以及双壳贝类作为产微囊藻毒素蓝藻对淡水进行中期污染的指示生物的用途。在对浮游植物群落进行特征描述的同时，测量了蓝藻生物量中的微囊藻毒素浓度（细胞内微囊藻毒素）以及双壳贝类中的微囊藻毒素浓度（游离微囊藻毒素，即未结合的微囊藻毒素，以及游离和与蛋白质结合的总积累微囊藻毒素）。两种贻贝都整合并突出了在连续两次水样采集期间环境中细胞内微囊藻毒素的存在，即使在低污染水平下也是如此，这表明它们适用于原位生物监测产微囊藻毒素的蓝藻。根据评估水体中微囊藻毒素污染水平的不同参数的优势和局限性，结合目标（管理、预防或全球评估）和所采用的监测策略对结果进行了讨论。
