Salat Alexandre P J, Williams Kim L, Chiu Suzanne, Eickmeyer David C, Kimpe Linda E, Blais Jules M, Crump Doug
Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, Ontario, Canada.
Environ Toxicol Chem. 2021 Jul;40(7):1883-1893. doi: 10.1002/etc.5040. Epub 2021 May 4.
Increases in oil sands mining operations in the Athabasca oil sands region have resulted in increased concentrations of polycyclic aromatic compounds (PACs) and heavy metals in aquatic systems located near surface mining operations. In the present study, sediment cores were collected from 3 lakes with varying proximity to surface mining operations to determine the differences in PAC concentrations. Sediment cores were separated into 2 sections-current mining (top; 2000-2017) and premining (bottom; pre-1945)-and extracts were prepared for in vitro screening using a well-established chicken embryonic hepatocyte (CEH) assay. Concentrations and composition of PACs varied between sites, with the highest ∑PACs in Saline Lake, 5 km from an active oil sands mine site. The proportion of alkylated PACs was greater than that of parent PACs in the top sediment sections compared with the bottom. Ethoxyresorufin-O-deethylase activity in CEH permitted the ranking of lake sites/core sections based on an aryl hydrocarbon receptor-mediated end point; mean median effect concentration values were lowest for the top cores from Saline Lake and another near-mining operations lake, referred to as WF1. A ToxChip polymerase chain reaction (PCR) array was used to evaluate gene expression changes across 43 target genes associated with numerous toxicological pathways following exposure to top and bottom sediment core extracts. The 2 study sites with the greatest ∑PAC concentrations (Saline Lake and WF1) had the highest gene expression alterations on the ToxChip PCR array (19 [top] and 17 [bottom]/43), compared with a reference site (13 [top] and 7 [bottom]/43). The avian in vitro bioassay was useful for identifying the toxicity of complex PAC extracts associated with variably contaminated sediment cores, supporting its potential use for hotspot identification and complex mixture screening. EnvironToxicol Chem 2021;40:1883-1893. © 2021 SETAC.
阿萨巴斯卡油砂地区油砂开采作业的增加，导致了位于露天采矿作业附近的水生系统中多环芳烃（PACs）和重金属浓度的上升。在本研究中，从3个与露天采矿作业距离不同的湖泊采集了沉积物岩芯，以确定PACs浓度的差异。沉积物岩芯被分为两个部分——当前开采层（顶部；2000 - 2017年）和开采前层（底部；1945年以前）——并使用成熟的鸡胚胎肝细胞（CEH）试验制备提取物用于体外筛选。不同地点的PACs浓度和组成各不相同，距离活跃油砂矿场5公里的盐湖中总PACs含量最高。与底部相比，顶部沉积物部分中烷基化PACs的比例高于母体PACs。CEH中的乙氧基异吩恶唑酮 - O - 脱乙基酶活性允许根据芳烃受体介导的终点对湖泊地点/岩芯部分进行排序；盐湖和另一个靠近采矿作业的湖泊（称为WF1）顶部岩芯的平均半数效应浓度值最低。使用ToxChip聚合酶链反应（PCR）阵列来评估暴露于顶部和底部沉积物岩芯提取物后，43个与众多毒理学途径相关的靶基因的基因表达变化。与一个参考地点（顶部13个[底部7个]/43个）相比，总PACs浓度最高的两个研究地点（盐湖和WF1）在ToxChip PCR阵列上的基因表达变化最大（顶部19个[底部17个]/43个）。鸟类体外生物测定法有助于识别与受不同程度污染的沉积物岩芯相关的复杂PAC提取物的毒性，支持其在热点识别和复杂混合物筛选中的潜在用途。《环境毒理学与化学》2021年；40：1883 - 1893。© 2021 SETAC。
