Norwegian Institute for Water Research (NIVA), Oslo, Norway.
Department of Biological Sciences, University of Bergen, Norway; Institute of Marine Research (IMR), Bergen, Norway.
Mar Environ Res. 2020 Dec;162:105155. doi: 10.1016/j.marenvres.2020.105155. Epub 2020 Sep 21.
Produced water (PW), a large byproduct of offshore oil and gas extraction, is reinjected to formations or discharged to the sea after treatment. The discharges contain dispersed crude oil, polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), metals, and many other constituents of environmental relevance. Risk-based regulation, greener offshore chemicals and improved cleaning systems have reduced environmental risks of PW discharges, but PW is still the largest operational source of oil pollution to the sea from the offshore petroleum industry. Monitoring surveys find detectable exposures in caged mussel and fish several km downstream from PW outfalls, but biomarkers indicate only mild acute effects in these sentinels. On the other hand, increased concentrations of DNA adducts are found repeatedly in benthic fish populations, especially in haddock. It is uncertain whether increased adducts could be a long-term effect of sediment contamination due to ongoing PW discharges, or earlier discharges of oil-containing drilling waste. Another concern is uncertainty regarding the possible effect of PW discharges in the sub-Arctic Southern Barents Sea. So far, research suggests that sub-arctic species are largely comparable to temperate species in their sensitivity to PW exposure. Larval deformities and cardiac toxicity in fish early life stages are among the biomarkers and adverse outcome pathways that currently receive much attention in PW effect research. Herein, we summarize the accumulated ecotoxicological knowledge of offshore PW discharges and highlight some key remaining knowledge needs.
生产水（PW）是海上油气开采的一种主要副产物，经处理后可回注地层或排入大海。排放物中含有分散的原油、多环芳烃（PAHs）、烷基酚（APs）、金属和许多其他具有环境相关性的成分。基于风险的监管、更环保的海上化学品和改进的清洁系统已经降低了 PW 排放的环境风险，但 PW 仍然是海上石油工业向海洋排放的最大的石油污染作业源。监测调查发现，在 PW 排放口下游数公里的笼养贻贝和鱼类中可检测到暴露，但生物标志物表明这些哨兵鱼只有轻度急性影响。另一方面，在底栖鱼类种群中，尤其是黑线鳕中，反复发现 DNA 加合物的浓度增加。尚不确定这些加合物是否是由于持续的 PW 排放导致的沉积物污染的长期影响，还是含油钻井废物的早期排放。另一个令人担忧的问题是，在亚北极的巴伦支海南部海域，PW 排放可能产生的影响存在不确定性。到目前为止，研究表明，亚北极物种在对 PW 暴露的敏感性方面与温带物种大致相当。鱼类早期生活阶段的幼虫畸形和心脏毒性是 PW 效应研究中目前受到广泛关注的生物标志物和不良结局途径之一。在此，我们总结了海上 PW 排放的累积生态毒理学知识，并强调了一些关键的遗留知识需求。
