Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada.
Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, T6G 2E3, Canada.
Environ Pollut. 2022 Oct 1;310:119886. doi: 10.1016/j.envpol.2022.119886. Epub 2022 Aug 5.
During hydraulic fracturing, wastewaters - termed flowback and produced water (FPW) - are created as a by-product during hydrocarbon extraction. Given the large volumes of FPW that a single well can produce, and the history of FPW release to surface water bodies, it is imperative to understand the hazards that hydraulic fracturing and FPW pose to aquatic biota. Using rainbow trout embryos as model organisms, we investigated impacts to cardio-respiratory system development and function following acute (48 h) and sub-chronic (28-day) FPW exposure by examining occurrences of developmental deformities, rates of embryonic respiration (MO), and changes in expression of critical cardiac-specific genes. FPW-exposed embryos had significantly increased rates of pericardial edema, yolk-sac edema, and tail/trunk curvatures at hatch. Furthermore, when exposed at three days post-fertilization (dpf), acute 5% FPW exposures significantly increased embryonic MO through development until 15 dpf, where a switch to significantly reduced MO rates was subsequently recorded. A similar trend was observed during sub-chronic 1% FPW exposures. Interestingly, at certain specific developmental timepoints, previous salinity exposure seemed to affect embryonic MO; a result not previously observed. Following acute FPW exposures, embryonic genes for cardiac development and function were significantly altered, although at termination of sub-chronic exposures, significant changes to these same genes were not found. Together, our evidence of induced developmental deformities, modified embryonic MO, and altered cardiac transcript expression suggest that cardio-respiratory tissues are toxicologically targeted following FPW exposure in developing rainbow trout. These results may be helpful to regulatory bodies when developing hazard identification and risk management protocols concerning hydraulic fracturing activities.
在水力压裂过程中，随着碳氢化合物的提取，会产生一种副产品废水，称为回流和产出水（FPW）。鉴于单井可产生大量 FPW，以及 FPW 向地表水释放的历史，了解水力压裂和 FPW 对水生生物群构成的危害至关重要。我们使用虹鳟鱼胚胎作为模型生物，通过检查胚胎发育畸形、胚胎呼吸率（MO）和关键心脏特异性基因表达的变化，研究了急性（48 小时）和亚慢性（28 天）FPW 暴露对心肺系统发育和功能的影响。FPW 暴露的胚胎在孵化时心包水肿、卵黄囊水肿和尾部/躯干弯曲的发生率明显增加。此外，当在受精后第三天（dpf）暴露时，急性 5%FPW 暴露通过发育显著增加了胚胎 MO，直到 15 dpf，随后记录到 MO 率显著降低。在亚慢性 1%FPW 暴露期间观察到类似的趋势。有趣的是，在某些特定的发育时间点，先前的盐度暴露似乎会影响胚胎 MO；这是以前没有观察到的结果。急性 FPW 暴露后，心脏发育和功能的胚胎基因明显改变，尽管在亚慢性暴露结束时，这些相同基因没有发现明显变化。总之，我们有证据表明，在发育中的虹鳟鱼中，FPW 暴露后会引起发育畸形、改变胚胎 MO 以及改变心脏转录表达，提示心肺组织是有毒的。这些结果可能有助于监管机构在制定水力压裂活动的危害识别和风险管理协议时提供参考。
