School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada; Environment and Climate Change Canada, Aquatic Contaminants Research Division, Burlington, Ontario, Canada.
Environment and Climate Change Canada, Aquatic Contaminants Research Division, Burlington, Ontario, Canada.
Environ Pollut. 2020 Jan;256:113398. doi: 10.1016/j.envpol.2019.113398. Epub 2019 Oct 16.
In aquatic environments, organisms such as freshwater mussels are likely exposed to complex contaminant mixtures related to industrial, agricultural, and urban activities. With growing interest in understanding the risk that chemical mixtures pose to mussels, this investigation focused on the effects of various waterborne contaminants (ammonia, chloride, copper, and potassium) and selected binary mixtures of these chemicals following a fixed-ratio design to Villosa iris glochidia and juvenile Lampsilis fasciola. In individual exposures, 48-h EC values were determined for V. iris glochidia exposed to ammonia chloride (7.4 [95% confidence interval (CI) 6.6-8.2] mg N/L), ammonia sulfate (8.4 [7.6-9.1] mg N/L), copper sulfate (14.2 [12.9-15.4] μg Cu/L), potassium chloride (12.8 [11.9-13.7] mg K/L), potassium sulfate (10.1 [8.9-11.2] mg K/L), and sodium chloride (480.5 [435.5-525.5] mg Cl/L). The 7-d LC values for juvenile L. fasciola were determined for potassium sulfate (45.0 [18.8-71.2] mg K/L), and sodium chloride (1738.2 [1418.6-2057.8] mg Cl/L). In Ontario these waterborne contaminants have been reported to co-occur, with concentrations exceeding the EC for both life stages at some locations. Data from binary mixture exposures for V. iris glochidia (chloride-ammonia, chloride-copper, and copper-ammonia) and juvenile L. fasciola (chloride-potassium) were analyzed using a regression-based, dose-response mixture analysis modeling framework. Results from the mixture analysis were used to determine if an additive model for mixture toxicity [concentration addition (CA) or independent action (IA)] best described the toxicity of each mixture and if deviation towards dose-ratio (DR) or dose-level (DL) synergism/antagonism (S/A) occurred. For all glochidia binary mixture exposures, CA was the best fit model with DL deviation reported for the chloride-copper mixture and DR deviation reported for the copper-ammonia mixture. Using the model deviation ratio (MDR), the observed toxicity in all three glochidia mixture exposures were adequately described by both CA (mean = 0.71) and IA (mean = 0.97) whereas the juvenile mixture exposure was only adequately described by CA (mean = 0.64; IA mean = 0.05).
在水生环境中，淡水贻贝等生物可能会接触到与工业、农业和城市活动有关的复杂污染物混合物。由于人们越来越关注了解化学混合物对贻贝构成的风险，本研究集中于研究各种水污染物（氨、氯、铜和钾）以及这些化学物质的选定二元混合物对美洲帘蛤幼虫和幼蚌（斑背无齿蚌和褶纹冠蚌）的影响。采用固定比例设计，对单独暴露的美洲帘蛤幼虫进行了 48 小时 EC 值测定，结果显示其暴露于氨-氯（7.4[95%置信区间（CI）6.6-8.2]mg N/L）、氨-硫酸盐（8.4[7.6-9.1]mg N/L）、硫酸铜（14.2[12.9-15.4]μg Cu/L）、氯化钾（12.8[11.9-13.7]mg K/L）、硫酸钾（10.1[8.9-11.2]mg K/L）和氯化钠（480.5[435.5-525.5]mg Cl/L）中。对幼蚌（斑背无齿蚌和褶纹冠蚌）的 7 天 LC 值进行了测定，结果显示其暴露于硫酸钾（45.0[18.8-71.2]mg K/L）和氯化钠（1738.2[1418.6-2057.8]mg Cl/L）中。在安大略省，这些水污染物已经被报道同时存在，在某些地点，其浓度超过了这两个生命阶段的 EC 值。采用基于回归的剂量-反应混合物分析建模框架，对美洲帘蛤幼虫（氯-氨、氯-铜和铜-氨）和幼蚌（氯-钾）的二元混合物暴露数据进行了分析。混合物分析的结果用于确定混合物毒性的加性模型[浓度加和（CA）或独立作用（IA）]是否最能描述每种混合物的毒性，以及是否存在向剂量比（DR）或剂量水平（DL）协同/拮抗（S/A）的偏差。对于所有的幼虫二元混合物暴露，CA 是最佳拟合模型，氯-铜混合物存在 DL 偏差，铜-氨混合物存在 DR 偏差。使用模型偏差比（MDR），所有三种幼虫混合物暴露的观察毒性均被 CA（均值=0.71）和 IA（均值=0.97）充分描述，而幼蚌混合物暴露仅被 CA（均值=0.64；IA 均值=0.05）充分描述。
