Central Valley Regional Water Quality Control Board, 11020 Sun Center Drive, #200, Rancho Cordova, CA, 95670, USA.
Department of Ocean Science, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.
Toxicon. 2021 Mar;192:1-14. doi: 10.1016/j.toxicon.2020.12.019. Epub 2021 Jan 8.
The global proliferation of toxin producing cyanobacterial blooms has been attributed to a wide variety of environmental factors with nutrient pollution, increased temperatures, and drought being three of the most significant. The current study is the first formal assessment of cyanotoxins in two impaired lakes, Canyon Lake and Lake Elsinore, in southern California that have a history of cyanobacterial blooms producing high biomass as measured by chl-a. Cyanotoxins in Lake Elsinore were detected at concentrations that persistently exceeded California recreational health thresholds, whereas Canyon Lake experienced persistent concentrations that only occasionally exceeded health thresholds. The study results are the highest recorded concentrations of microcystins, anatoxin-a, and cylindrospermopsin detected in southern California lakes. Concentrations exceeded health thresholds that caused both lakes to be closed for recreational activities. Cyanobacterial identifications indicated a high risk for the presence of potentially toxic genera and agreed with the cyanotoxin results that indicated frequent detection of multiple cyanotoxins simultaneously. A statistically significant correlation was observed between chlorophyll-a (chl-a) and microcystin concentrations for Lake Elsinore but not Canyon Lake, and chl-a was not a good indicator of cylindrospermopsin, anatoxin-a, or nodularin. Therefore, chl-a was not a viable screening indicator of cyanotoxin risk in these lakes. The study results indicate potential acute and chronic risk of exposure to cyanotoxins in these lakes and supports the need for future monitoring efforts to help minimize human and domestic pet exposure and to better understand potential effects to wildlife. The frequent co-occurrence of complex cyanotoxin mixtures further complicates the risk assessment process for these lakes given uncertainty in the toxicology of mixtures.
具有产毒能力的蓝藻水华在全球范围内的扩散归因于多种环境因素，其中营养污染、温度升高和干旱是三个最重要的因素。本研究首次对加利福尼亚州南部两个受损湖泊（峡谷湖和埃尔西诺湖）中的蓝藻毒素进行了正式评估，这两个湖泊历史上曾发生过蓝藻水华，其生物量高，可通过chl-a 进行测量。在埃尔西诺湖中检测到的蓝藻毒素浓度持续超过加利福尼亚州休闲健康阈值，而峡谷湖则经历了持续浓度，仅偶尔超过健康阈值。研究结果是在加利福尼亚州南部湖泊中检测到的微囊藻毒素、鱼腥藻毒素-a 和柱孢藻毒素的最高记录浓度。浓度超过了健康阈值，导致两个湖泊都关闭了休闲活动。蓝藻菌的鉴定表明存在潜在有毒属的高风险，并且与蓝藻毒素结果一致，表明同时频繁检测到多种蓝藻毒素。在埃尔西诺湖中观察到叶绿素-a (chl-a) 和微囊藻毒素浓度之间存在显著的相关性，但在峡谷湖中没有，chl-a 不是柱孢藻毒素、鱼腥藻毒素-a 或节球藻毒素的良好指示物。因此，chl-a 不是这些湖泊中蓝藻毒素风险的可行筛选指标。研究结果表明，这些湖泊存在暴露于蓝藻毒素的潜在急性和慢性风险，需要进行未来的监测工作，以帮助最大限度地减少人类和宠物的暴露，并更好地了解对野生动物的潜在影响。鉴于混合物毒理学的不确定性，这些湖泊中复杂蓝藻毒素混合物的频繁共现进一步使风险评估过程复杂化。
