James Cook University, College of Science & Engineering, Townsville, Queensland 4810, Australia; AIMS@JCU, Division of Research & Innovation, James Cook University and Australian Institute of Marine Science, Townsville 4810, Queensland, Australia; Australian Institute of Marine Science, Townsville 4810, Queensland, Australia.
Australian Institute of Marine Science, Crawley 6009, Western Australia, Australia.
Sci Total Environ. 2020 Jun 10;720:137486. doi: 10.1016/j.scitotenv.2020.137486. Epub 2020 Feb 21.
Oil pollution remains a significant local threat to shallow tropical coral reef environments, but the environmental conditions typical of coral reefs are rarely considered in oil toxicity testing and risk assessments. Here we review the effects of three environmental co-factors on petroleum oil toxicity towards coral reef organisms, and show that the impacts of oil pollution on coral reef taxa can be exacerbated by environmental conditions commonly encountered in tropical reef environments. Shallow reefs are routinely exposed to high levels of ultraviolet radiation (UVR), which can substantially increase the toxicity of some oil components through phototoxicity. Exposure to UVR represents the most likely and harmful environmental co-factor reviewed here, leading to an average toxicity increase of 7.2-fold across all tests reviewed. The clear relevance of UVR co-exposure and its strong influence on tropical reef oil toxicity highlights the need to account for UVR as a standard practice in future oil toxicity studies. Indeed, quantifying the influence of UVR on toxic thresholds of oil to coral reef species is essential to develop credible oil spill risk models required for oil extraction developments, shipping management and spill responses in the tropics. The few studies available indicate that co-exposure to elevated temperature and low pH, both within the range of current daily and seasonal fluctuations and/or projected under continued climate change, can increase oil toxicity on average by 3.0- and 1.3-fold, respectively. While all three of the reviewed environmental co-factors have the potential to substantially increase the impacts of oil pollution in shallow reef environments, their simultaneous effects have not been investigated. Assessments of the combined effects of oil pollution, UVR, temperature and low pH will become increasingly important to identify realistic hazard thresholds suitable for future risk assessments over the coming century.
石油污染仍然是浅海热带珊瑚礁环境的一个重大局部威胁，但在石油毒性测试和风险评估中很少考虑到珊瑚礁的环境条件。在这里，我们回顾了三个环境共同因素对石油毒性对珊瑚礁生物的影响，并表明在热带珊瑚礁环境中常见的环境条件会加剧石油污染对珊瑚礁分类群的影响。浅珊瑚礁经常暴露在高水平的紫外线辐射（UVR）下，这会通过光毒性使一些石油成分的毒性大大增加。UVR 暴露是这里审查的最可能和最有害的环境共同因素之一，导致所有审查测试的平均毒性增加了 7.2 倍。UVR 共同暴露的明显相关性及其对热带珊瑚礁石油毒性的强烈影响突出表明，在未来的石油毒性研究中，需要将 UVR 作为标准做法加以考虑。事实上，量化 UVR 对珊瑚礁物种石油毒性阈值的影响对于开发可信的石油泄漏风险模型至关重要，这些模型对于石油开采开发、航运管理和热带地区的溢油应对都是必需的。现有的少数研究表明，在当前的日常和季节性波动范围内或在持续的气候变化下，共同暴露于高温和低 pH 值（分别提高了 3.0 倍和 1.3 倍），会平均增加石油毒性。虽然审查的三个环境共同因素都有可能大大增加浅海珊瑚礁环境中石油污染的影响，但它们的同时影响尚未得到调查。评估石油污染、UVR、温度和低 pH 值的综合影响将变得越来越重要，以确定适合未来风险评估的现实危害阈值，这将是未来一个世纪的重要任务。
