AGAT Laboratories, 9770 Route Transcanadienne, St. Laurent, QC H4S 1V9, Canada.
AGAT Laboratories, 9770 Route Transcanadienne, St. Laurent, QC H4S 1V9, Canada.
Ecotoxicol Environ Saf. 2018 Nov 30;164:331-343. doi: 10.1016/j.ecoenv.2018.08.010. Epub 2018 Aug 18.
This paper presents the results of two different studies investigating the acute and chronic toxicity of two blends of diluted bitumens ("dilbit") and weathered dilbit on freshwater fish and invertebrates after exposure to different concentrations of physically-dispersed (water accommodated fraction; WAF) and chemically-dispersed (chemically-enhanced WAF; CEWAF). The first study evaluated the acute and chronic toxicity of weathered, unweathered and dispersed Access Western Blend (AWB) dilbit on Fathead minnow (Pimephales promelas). In the second study, acute and chronic toxicity of weathered and unweathered Cold Lake Blend (CLB) dilbit was assessed on Rainbow trout (Oncorhynchus mykiss), and two invertebrate species, Daphnia (Daphnia magna) and Ceriodaphnia (Ceriodaphnia dubia). For Fathead minnow, unweathered AWB WAF demonstrated a significantly higher acute toxicity (LC50-96 h = 0.628 g/L) compared to the weathered AWB WAF (LC50-96 h = 2.06 g/L). Chronic toxicity tests showed that Fathead minnow lethality was also higher for unweathered AWB (LC50-7 d = 0.593 g/L) compared to the weathered AWB (LC50-7 d = 1.31 g/L) whereas larval growth toxicity was lower for unweathered AWB (IC25-7 d=0.312 g/L) compared to the weathered dilbit (IC25-7 d = 0.096 g/L). Rainbow trout exposed to unweathered CLB demonstrated a significantly higher toxicity (LC50-96 h = 5.66 g/L) compared to the weathered CLB (LC50 > 18 g/L). Lethality (LC50 = 6.43 g/L) was observed in Ceriodaphnia exposed to the CLB WAF while no mortality was observed with the weathered CLB. The reproductive effects on Ceriodaphnia were greater with the CLB (IC25 <1.0) than with the weathered CLB (IC25 = 3.99 g/L). Volatile organic compounds (VOC), polycyclic aromatic hydrocarbons (PAH) and total petroleum hydrocarbons (TPH) increased as the dilbit CLB and AWB WAF concentrations increased. The total VOC and the total PAHs (including the alkylated PAHs) presented similar concentrations in the weathered and unweathered AWB WAF. These compounds seem therefore not be affected by the AWB WAF weathering process. However, VOC and PAH concentrations decreased significantly in the Rainbow trout and Ceriodaphnia toxicity tests using the weathered CLB WAF. VOC and PAH concentrations were also lower in the weathered AWB CEWAF used for Fathead minnow chronic study.
本文介绍了两项不同研究的结果，这些研究调查了两种稀释沥青混合物（“稀释沥青”）和风化稀释沥青在暴露于不同浓度的物理分散（水容纳部分；WAF）和化学分散（化学增强 WAF；CEWAF）后对淡水鱼类和无脊椎动物的急性和慢性毒性。第一项研究评估了风化、未风化和分散的 Access Western Blend（AWB）稀释沥青对黑头呆鱼（Pimephales promelas）的急性和慢性毒性。在第二项研究中，评估了风化和未风化的 Cold Lake Blend（CLB）稀释沥青对虹鳟鱼（Oncorhynchus mykiss）以及两种无脊椎动物物种，大型溞（Daphnia magna）和似指环虫（Ceriodaphnia dubia）的急性和慢性毒性。对于黑头呆鱼，未风化的 AWB WAF 表现出明显更高的急性毒性（LC50-96 h = 0.628 g/L），而风化的 AWB WAF（LC50-96 h = 2.06 g/L）。慢性毒性试验表明，未风化的 AWB 对黑头呆鱼的致死率也更高（LC50-7 d = 0.593 g/L），而风化的 AWB（LC50-7 d = 1.31 g/L），而未风化的 AWB 的幼虫生长毒性较低（IC25-7 d = 0.312 g/L），而风化的稀释沥青（IC25-7 d = 0.096 g/L）。暴露于未风化的 CLB 的虹鳟鱼表现出明显更高的毒性（LC50-96 h = 5.66 g/L），而风化的 CLB（LC50 > 18 g/L）。在暴露于 CLB WAF 的似指环虫中观察到致死率（LC50 = 6.43 g/L），而在暴露于风化的 CLB 时未观察到死亡率。CLB 对似指环虫的生殖影响大于风化的 CLB（IC25 <1.0）。挥发性有机化合物（VOC）、多环芳烃（PAH）和总石油烃（TPH）随着稀释沥青 CLB 和 AWB WAF 浓度的增加而增加。在风化和未风化的 AWB WAF 中，总 VOC 和总多环芳烃（包括烷基化多环芳烃）的浓度相似。因此，这些化合物似乎不受 AWB WAF 风化过程的影响。然而，在使用风化的 CLB WAF 进行虹鳟鱼和似指环虫毒性试验时，VOC 和 PAH 浓度显著降低。在用于黑头呆鱼慢性研究的风化 AWB CEWAF 中，VOC 和 PAH 浓度也较低。
