Institute of Environmental Sustainability, Loyola University Chicago, 1032 W. Sheridan Road, Chicago, IL, 60660, USA.
School of Earth and Environmental Sciences, University of Minnesota, 116 Church Street SE, Minneapolis, MN, 55455, USA.
Toxicon. 2021 Jul 15;197:33-39. doi: 10.1016/j.toxicon.2021.04.010. Epub 2021 Apr 16.
Cyanobacterial blooms present a threat to many waterbodies around the world used for drinking water and recreational purposes. Toxicology tests, such as the Thamnotoxkit-F which uses the cladoceran T. platyurus, have been employed to assess the health hazards that these blooms may pose to the public. However, reported median lethal concentrations (LC) of microcystin -LR to T. platyurus vary significantly from one study to the next. The variation in solvent type and concentrations used to dissolve microcystin -LR in preparation for toxicity experiments may be contributing to the variations in LC values found in the literature. The primary goal of this study was to determine what solvents and their corresponding concentrations can be used for microcystin -LR testing using T. platyurus without artifactually impacting LC values. All toxicity testing was completed using glassware as polystyrene containers have been shown to sorb microcystin. Microcystin -LR LC values for T. platyurus were determined using United States Environmental Protection Agency (US EPA) moderately hard standard freshwater as a control for comparison with systems that were prepared using dimethyl sulfoxide or methanol to dissolve microcystin -LR. Low levels of dimethyl sulfoxide (2%) or methanol (1%) did not impact LC values of microcystin -LR to T. platyurus compared to US EPA moderately hard standard freshwater diluted in microcystin -LR. However, higher levels of dimethyl sulfoxide (4%) and methanol (1.4% and 4%) did lower the LC for microcystin -LR to T. platyurus, consistent with the toxicity of these solvents to T. platyurus when dosed in the absence of microcystin -LR. Researchers need to report the type and concentrations of solvents used in toxicity tests using cyanotoxins in order to ensure that results can be intercompared appropriately. Furthermore, researchers need to use caution when using organic solvents such as dimethyl sulfoxide or methanol to ensure that these solvents are not causing significant mortality in toxicity testing.
蓝藻水华对全球许多用于饮用水和娱乐目的的水体构成威胁。毒理学测试，如使用狭甲轮虫 T. platyurus 的 Thamnotoxkit-F，已被用于评估这些水华可能对公众造成的健康危害。然而，从一项研究到另一项研究，微囊藻毒素-LR 对 T. platyurus 的报告中位数致死浓度 (LC) 差异很大。在准备毒性实验时，用于溶解微囊藻毒素-LR 的溶剂类型和浓度的变化可能导致文献中 LC 值的变化。本研究的主要目标是确定使用 T. platyurus 进行微囊藻毒素-LR 测试可以使用哪些溶剂及其相应浓度，而不会人为地影响 LC 值。所有毒性测试均使用玻璃器皿完成，因为已证明聚苯乙烯容器会吸附微囊藻毒素。使用美国环保署 (US EPA) 中度硬标准淡水作为对照，与使用二甲基亚砜或甲醇溶解微囊藻毒素-LR 制备的系统进行比较，确定了 T. platyurus 的微囊藻毒素-LR LC 值。与 US EPA 中度硬标准淡水相比，低浓度的二甲基亚砜 (2%) 或甲醇 (1%) 对 T. platyurus 微囊藻毒素-LR 的 LC 值没有影响。然而，较高浓度的二甲基亚砜 (4%) 和甲醇 (1.4% 和 4%) 确实降低了 T. platyurus 微囊藻毒素-LR 的 LC 值，与微囊藻毒素-LR 不存在时这些溶剂对 T. platyurus 的毒性一致。研究人员需要报告使用毒藻素进行毒性测试中使用的溶剂类型和浓度，以确保可以适当比较结果。此外，研究人员在使用二甲基亚砜或甲醇等有机溶剂时需要小心谨慎，以确保这些溶剂不会在毒性测试中导致显着的死亡率。
