School of Environment & Sustainability, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SaskatchewanS7N 5E2, Canada.
Department of Physical & Environmental Sciences, University of Toronto, 1265 Military Trail, Toronto, OntarioM1C 1A4, Canada.
Environ Sci Technol. 2022 Dec 20;56(24):17902-17912. doi: 10.1021/acs.est.2c06928. Epub 2022 Nov 22.
The risk of human exposure to cyanotoxins is partially influenced by the location of toxin-producing cyanobacteria in waterbodies. Cyanotoxin production can occur throughout the water column, with deep water production representing a potential public health concern, specifically for drinking water supplies. Deep cyanobacteria layers are often unreported, and it remains to be seen if lower incident rates reflect an uncommon phenomenon or a monitoring bias. Here, we examine Sunfish Lake, Ontario, Canada as a case study lake with a known deep cyanobacteria layer. Cyanotoxin and other bioactive metabolite screening revealed that the deep cyanobacteria layer was toxigenic [0.03 μg L microcystins (max) and 2.5 μg L anabaenopeptins (max)]. The deep layer was predominantly composed of (exhibiting a lower cyanotoxin cell quota), with (exhibiting a higher cyanotoxin cell quota) found at background levels. The co-occurrence of multiple toxigenic species underscores the importance of routine surveillance for prompt identification leading to early intervention. For instance, microcystin concentrations in Sunfish Lake are currently below national drinking water thresholds, but shifting environmental conditions (e.g., in response to climate change or nutrient modification) could fashion an environment favoring , creating a scenario of greater cyanotoxin production. Future work should monitor the entire water column to help build predictive capacities for identifying waterbodies at elevated risk of developing deep cyanobacteria layers to safeguard drinking water supplies.
人类接触到蓝藻毒素的风险部分受产生蓝藻毒素的蓝藻在水体中的位置影响。蓝藻毒素的产生可以发生在整个水柱中，深层水的产生是一个潜在的公共卫生关注点，特别是对于饮用水供应。深层蓝藻层通常未被报告，较低的发病率是否反映了不常见的现象还是监测偏差仍有待观察。在这里，我们以加拿大安大略省的 Sunfish Lake 为例研究了一个已知有深层蓝藻层的案例湖。蓝藻毒素和其他生物活性代谢物的筛选表明，深层蓝藻层具有产毒能力[最高 0.03μg/L 微囊藻毒素和 2.5μg/L 节旋藻肽（最高）]。深层主要由组成（表现出较低的蓝藻毒素细胞配额），背景水平下发现 （表现出较高的蓝藻毒素细胞配额）。多种产毒的 物种的共存突出了常规监测的重要性，以便及时识别，从而进行早期干预。例如，Sunfish Lake 中的微囊藻毒素浓度目前低于国家饮用水标准，但环境条件的变化（例如，应对气候变化或营养物修改）可能会形成有利于 的环境，从而产生更多蓝藻毒素的产生。未来的工作应该监测整个水柱，以帮助建立识别具有较高发展深层蓝藻层风险的水体的预测能力，从而保障饮用水供应。
