Institut national de la recherche scientifique (INRS), 490 rue de la Couronne, Québec City, QC, G1K 9A9, Canada; Direction générale de la coordination scientifique et du Centre d'expertise en analyse environnementale du Québec, Ministère de l'Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (MELCCFP), Québec City, QC, G1P 3W8, Canada.
Direction générale de la coordination scientifique et du Centre d'expertise en analyse environnementale du Québec, Ministère de l'Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (MELCCFP), Québec City, QC, G1P 3W8, Canada.
Environ Pollut. 2023 Jun 15;327:121497. doi: 10.1016/j.envpol.2023.121497. Epub 2023 Mar 24.
Diluted bitumen (dilbit) is an unconventional oil produced by the oil sands industry in Canada. Despite the knowledge available on hydrocarbon toxicity, the effects of diluted bitumen on benthic organisms are still largely unknown. Moreover, in Quebec there are only provisional threshold values of 164 mg/kg C-C for chronic effects and 832 mg/kg for acute effects. The protectiveness of these values for benthic invertebrates has not been tested for heavy unconventional oils such as dilbit. Two benthic organisms, the larvae of Chironomus riparius and Hyalella azteca, were exposed to these two concentrations and to an intermediate concentration (416 mg/kg) of two dilbits (DB1 and DB2) and a heavy conventional oil (CO). The aim of the study was to assess the sublethal and lethal effects of spiked sediment by dilbit. The oil was rapidly degraded in the sediment, especially in the presence of C. riparius. Amphipods were much more sensitive to oil than chironomids. LC values for H. azteca were 199 mg/kg C-C for DB1, 299 mg/kg for DB2 and 8.42 mg/kg for CO compared to LC values for C. riparius of 492 mg/kg for DB1, 563 mg/kg for DB2 and 514 mg/kg for CO. The size of the organisms was reduced compared to controls for both species. The defense enzymes (GST, GPx, SOD and CAT) were not good biomarkers in these two organisms for this type of contamination. The current provisional sediment quality criteria seem too permissive for heavy oils and should be lowered.
稀释沥青（dilbit）是加拿大油砂产业生产的一种非常规石油。尽管人们对碳氢化合物毒性有一定的了解，但稀释沥青对底栖生物的影响仍知之甚少。此外，在魁北克，只有针对慢性影响的 164mg/kg C-C 和针对急性影响的 832mg/kg 的暂定阈值。这些值对类似于 dilbit 的重质非常规油是否能保护底栖无脊椎动物尚未经过测试。两种底栖生物，摇蚊幼虫和亚得里亚海螯虾，暴露于这两种浓度以及两种稀释沥青（DB1 和 DB2）和一种重质常规油（CO）的中间浓度（416mg/kg）下。该研究旨在评估受污染沉积物中添加的稀释沥青的亚致死和致死效应。油在沉积物中迅速降解，特别是在有摇蚊幼虫存在的情况下。相比之下，水蚤对油的敏感性比摇蚊高得多。对于 H. azteca，DB1 的 LC 值为 199mg/kg C-C，DB2 的 LC 值为 299mg/kg C-C，CO 的 LC 值为 8.42mg/kg C-C，而对于 C. riparius，DB1 的 LC 值为 492mg/kg C-C，DB2 的 LC 值为 563mg/kg C-C，CO 的 LC 值为 514mg/kg C-C。与对照相比，两种物种的个体大小都减小了。对于这两种生物，防御酶（GST、GPx、SOD 和 CAT）不是此类污染的良好生物标志物。目前的暂定沉积物质量标准对重油来说过于宽松，应该降低。
