Institut national de la recherche scientifique (INRS), 490 rue de la Couronne, Québec City, QC G1K 9A9, Canada; Centre d'expertise en analyse environnementale du Québec, Ministère de l'Environnement et de la Lutte contre les changements climatiques (MELCC), Québec City, QC G1P 3W8, Canada.
Centre d'expertise en analyse environnementale du Québec, Ministère de l'Environnement et de la Lutte contre les changements climatiques (MELCC), Québec City, QC G1P 3W8, Canada.
Ecotoxicol Environ Saf. 2022 Jun 1;237:113554. doi: 10.1016/j.ecoenv.2022.113554. Epub 2022 Apr 26.
The oil sands industry in Canada, produces heavy unconventional oils, diluted for transport and called diluted bitumen. However, despite advances in our knowledge of the ecotoxicological risk that these products represent, their effects on benthic organisms following a spill are still largely unknown. In order to fill these gaps, this study aims to determine the lethal and sublethal effects of two diluted bitumens (Bluesky and Cold Lake) and one conventional oil (Lloydminster) for two freshwater benthic invertebrates: Chironomus riparius and Hyalella azteca. The objective of this study is to assess the toxicity of dissolved hydrocarbons, resulting from the physical dispersion of oil, immediately after a spill on the benthic invertebrates. To this end, organisms were exposed for 7 days for chironomids and 14 days for amphipods to a fraction containing soluble hydrocarbons (WAF: water accommodated fraction; 10 g/L, 18 h of agitation, followed by 6 h of sedimentation) with natural or artificial sediment. After exposure, the effects of hydrocarbons were determined using size, mortality, and antioxidant capacities. Dissolved hydrocarbons induced mortality for both species, but these hydrocarbons disappeared very quickly from the water column, regardless of the oil type. The amphipods were sensitive to both types of oil while the chironomids were only sensitive to diluted bitumens. The presence of a natural sediment seems to provide a protective role against dissolved hydrocarbons. The antioxidant enzymes measured (CAT, SOD and GPx) do not appear to be relevant biomarkers for the exposure of these organisms to diluted bitumen.
加拿大的油砂产业生产重质非常规油，为便于运输进行了稀释，称为稀释沥青。然而，尽管我们对这些产品所代表的生态毒理学风险的认识有所提高，但它们在溢油事件后对底栖生物的影响仍在很大程度上未知。为了填补这些空白，本研究旨在确定两种稀释沥青（Bluesky 和 Cold Lake）和一种常规油（Lloydminster）对两种淡水底栖无脊椎动物：摇蚊幼虫和食蚊鱼的致死和亚致死效应。本研究的目的是评估溢油后底栖无脊椎动物立即发生的物理分散的油溶性烃类的毒性。为此，摇蚊幼虫暴露 7 天，食蚊鱼暴露 14 天，接触含有可溶烃类的水层（WAF：水容纳分数；10 g/L，搅拌 18 小时，然后沉降 6 小时），与天然或人工沉积物一起。暴露后，使用大小、死亡率和抗氧化能力来确定烃类的影响。溶解烃类导致两种物种死亡，但无论油的类型如何，这些烃类很快从水柱中消失。两种油类都对该种桡足类敏感，而摇蚊幼虫只对稀释沥青敏感。天然沉积物的存在似乎对溶解烃类具有保护作用。测量的抗氧化酶（CAT、SOD 和 GPx）似乎不是这些生物暴露于稀释沥青的相关生物标志物。
