Centre for Agroecology, Water and Resilience, Coventry University, Coventry, UK.
Queensland Department of Environment and Science, Information Technology and Innovation, Brisbane, QLD, Australia.
Environ Sci Pollut Res Int. 2018 Feb;25(4):3151-3169. doi: 10.1007/s11356-017-1097-5. Epub 2018 Jan 14.
Triazine and urea herbicides are two groups of photosystem II inhibiting herbicides frequently detected in surface, ground and marine waters. Yet, there are few water quality guidelines for herbicides. Ecotoxicity thresholds (ETs) for ametryn, hexazinone and simazine (triazine herbicides) and diuron (a urea herbicide) were calculated using the Australian and New Zealand method for deriving guideline values to protect fresh and marine ecosystems. Four ETs were derived for each chemical and ecosystem that should theoretically protect 99, 95, 90 and 80% of species (i.e. PC99, PC95, PC90 and PC80, respectively). For all four herbicides, the phototrophic species were significantly more sensitive than non-phototrophic species, and therefore, only the former data were used to calculate the ETs. Comparison of the ET values to measured concentrations in 2606 samples from 15 waterways that discharge to the Great Barrier Reef (2011-2015) found three exceedances of the simazine PC99, regular exceedances (up to 30%) of the PC99 in a limited number of rivers for ametryn and hexazinone and frequent (> 40%) exceedances of the PC99 and PC95 ETs in at least four waterways for diuron. There were no exceedances of the marine ETs in inshore reef areas. Further, ecotoxicity data are required for ametryn and hexazinone to fresh and marine phototrophic species, for simazine to marine phototrophic species, for tropical phototrophic species, repeated pulse exposures and long-term (2 to 12 months) exposures to environmentally relevant concentrations.
三嗪类和脲类除草剂是两组常见于地表水、地下水和海水中的光合系统 II 抑制剂除草剂。然而，针对这些除草剂的水质准则却很少。本研究采用澳大利亚和新西兰制定导则值的方法，计算了莠去津、六嗪酮和西玛津（三嗪类除草剂）以及敌草隆（一种脲类除草剂）对淡水和海洋生态系统的生态毒性阈值（ET）。针对每种化学物质和生态系统，分别为 4 个 ET 值，这些值理论上应分别保护 99%、95%、90%和 80%的物种（即 PC99、PC95、PC90 和 PC80）。对于所有 4 种除草剂，光养生物物种的敏感性明显高于非光养生物物种，因此，仅使用前一类数据来计算 ET 值。将 ET 值与 2011 年至 2015 年期间从排入大堡礁的 15 条水道中采集的 2606 个样本中的实测浓度进行比较，发现有 3 个样本的西玛津 PC99 浓度超过限值，在少数几条河流中莠去津和六嗪酮的 PC99 浓度也出现超过限值（最高达 30%），而在至少 4 条水道中，敌草隆的 PC99 和 PC95 ET 值频繁（>40%）超过限值。近岸珊瑚礁区域未出现超过海洋 ET 值的情况。此外，还需要莠去津和六嗪酮对淡水和海洋光养生物物种、西玛津对海洋光养生物物种、热带光养生物物种、重复脉冲暴露和长期（2 至 12 个月）暴露于环境相关浓度的生态毒性数据。
