Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire, UK.
Environ Int. 2010 Aug;36(6):521-6. doi: 10.1016/j.envint.2010.04.003. Epub 2010 May 1.
Triclosan (TCS) is used in a range of domestic products and may reach aquatic environments after disposal "down-the-drain". Reach-specific TCS concentrations were predicted using the stochastic water quality model LF2000-WQX for two heavily urbanised regions in England, encompassing some of the most densely populated areas (including London and Birmingham). The model was calibrated using effluent TCS concentration data derived from a national monitoring programme which included 21 sewage treatment plants (STPs). The assessment represents a significant improvement on previous higher-tier modelling studies of TCS because it is applied to a much wider area compared with that hitherto evaluated. Initial results suggest that total TCS concentrations exceed a conservative Predicted No Effect Concentration of 69 ng L(-1) in <15% of river reaches. However, TCS is an ionisable compound with a pKa of about 8. In many rivers, a significant fraction of TCS will exist as the phenolate anion, which has much lower toxicity than neutral TCS. Concentrations of the neutral form of TCS were, therefore, calculated using measured data on river water pH. Predicted neutral concentrations in most river reaches were significantly lower than those for total TCS, often by >50%, reducing the associated risks. Further work is needed to better characterise the aquatic toxicity of TCS to fresh water organisms under a range of environmentally relevant conditions.
三氯生（TCS）被广泛应用于各类家用产品中，在丢弃后可能会“随污水排入”水生环境。本研究采用随机水质模型 LF2000-WQX 预测了英国两个高度城市化地区（包括伦敦和伯明翰）中特定水域的 TCS 浓度。该模型使用全国性监测计划中的污水 TCS 浓度数据进行了校准，该计划涵盖了 21 个污水处理厂（STP）。与之前的 TCS 高级别建模研究相比，该评估具有重大改进，因为它应用于比以往评估更广泛的区域。初步结果表明，在不到 15%的河流中，总 TCS 浓度超过了保守的无影响预测浓度 69ng/L。然而，TCS 是一种具有约 8 的 pKa 值的可离子化化合物。在许多河流中，TCS 将以酚盐阴离子的形式存在，其毒性比中性 TCS 低得多。因此，使用河流水 pH 值的实测数据计算了 TCS 的中性形式浓度。大多数河流中 TCS 的中性浓度明显低于总 TCS 浓度，通常降低超过 50%，从而降低了相关风险。需要进一步研究以更好地描述 TCS 在各种环境相关条件下对淡水生物的水生毒性。
