The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
Environ Int. 2020 Mar;136:105464. doi: 10.1016/j.envint.2020.105464. Epub 2020 Jan 8.
In animals, retinoic acids (RAs), one of the main derivatives of vitamin A, are crucial for a variety of physiological processes. RAs, including all-trans-RA, 9-cis-RA, 13-cis-RA, and their corresponding metabolites (i.e., all-trans-4-oxo-RA, 9-cis-4-oxo-RA and 13-cis-4-oxo-RA) can be excreted through urination from humans and animals. Sewage treatment plants (STPs) are a significant source of RAs and 4-oxo-RAs into aquatic environments. RAs and 4-oxo-RAs can be identified and quantified by use of liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). RAs and 4-oxo-RAs have been reported in various environmental matrices including rivers, lakes, reservoirs and coastal marine environments as well as in sewage effluents discharged from STPs. Greater concentrations of RAs and 4-oxo-RAs have been observed during blooms of cyanobacteria and microalgae, suggesting that cyanobacteria and microalgae are natural sources of RAs and 4-oxo-RAs in aquatic environments. These potential sources of RAs and 4-oxo-RAs raise concerns about their concentrations and risks in aquatic environments because excessive intake of these chemicals can result in abnormal morphological development in animals. Teratogenic effects were observed in amphibians, fish embryos, gastropods, mammals and birds when exposed to RAs. This review summarizes sources, concentrations, adverse effects and ecological risks of RAs and 4-oxo-RAs in aquatic environments. An interim, predicted no-effect concentration (PNEC) of RAs (in terms of at-RA) for freshwater environments was determined to be 3.93 ng/L at-RA equivalents. Based on limited data on concentrations of RAs in freshwater ecosystems, their hazard quotients were found to range from zero to 16.41, depending on the environmental conditions of receiving waters. Ecological risks of RAs in marine environments are yet to be explored due to the paucity of data related to both their concentrations in marine environment and toxic potencies to marine species. This review updates current knowledge of RAs and 4-oxo-RAs in aquatic environments and calls for more studies on their concentrations and fate in aquatic environments, especially estuarine and coastal marine environments with a view to enabling a comprehensive assessment of their ecological risks around the globe.
在动物中，视黄酸（RAs）是维生素 A 的主要衍生物之一，对各种生理过程至关重要。RAs，包括全反式-RA、9-顺式-RA、13-顺式-RA 及其相应的代谢物（即全反式-4-氧代-RA、9-顺式-4-氧代-RA 和 13-顺式-4-氧代-RA）可以通过人类和动物的尿液排出。污水处理厂（STP）是 RA 和 4-氧代-RA 进入水生环境的重要来源。可以使用液相色谱-串联质谱（LC-MS/MS）来鉴定和定量 RAs 和 4-氧代-RAs。已经在包括河流、湖泊、水库和沿海水域以及从 STP 排放的污水中的各种环境基质中报告了 RAs 和 4-氧代-RAs。在蓝藻和微藻大量繁殖期间，观察到 RAs 和 4-氧代-RAs 的浓度更高，这表明蓝藻和微藻是水生环境中 RAs 和 4-氧代-RAs 的天然来源。这些 RAs 和 4-氧代-RAs 的潜在来源引起了人们对其在水生环境中的浓度和风险的关注，因为过量摄入这些化学物质会导致动物形态发育异常。在暴露于 RAs 的情况下，两栖动物、鱼类胚胎、腹足类动物、哺乳动物和鸟类中观察到致畸作用。本综述总结了水生环境中 RAs 和 4-氧代-RAs 的来源、浓度、不良影响和生态风险。确定了淡水环境中 RAs（以 at-RA 计）的暂定无影响浓度（PNEC）为 3.93ng/L at-RA 当量。基于有关淡水生态系统中 RAs 浓度的有限数据，发现其危险商数范围为零至 16.41，具体取决于受纳水体的环境条件。由于有关海洋环境中 RAs 的浓度及其对海洋物种的毒性潜力的数据稀缺，因此尚未探讨海洋环境中 RAs 的生态风险。本综述更新了水生环境中 RAs 和 4-氧代-RAs 的最新知识，并呼吁开展更多关于其在水生环境中的浓度和归宿的研究，特别是对具有河口和沿海水域的研究，以期能够对其在全球范围内的生态风险进行全面评估。
