Department of Civil and Environmental Engineering, National University of Singapore, Singapore.
Department of Civil and Environmental Engineering, National University of Singapore, Singapore.
Sci Total Environ. 2017 Jan 1;574:1439-1447. doi: 10.1016/j.scitotenv.2016.08.091. Epub 2016 Aug 29.
This study involved a comprehensive thirteen month survey of synthetic musks, triclosan (TCS) and methyl triclosan (MTCS) in surface water, as well as suspended particular matter (SPM) and bottom sediments in a tropical urban catchment in Singapore. The polycyclic musk, Galaxolide (HHCB), exhibited the highest concentration among musk compounds, ranging from 5.16 to 42.9ng/L in surface water, 11.0 to 108ng/g dry wt. in sediments and 44.1 to 81.3ng/g dry wt. in SPM. Concentrations of musk ketone, the dominant nitroaromatic musk, ranged from 0.08 to 6.45ng/L in water, 0.082 to 0.72ng/g dry wt. in sediments and 1.75 to 5.50ng/g dry wt. in SPM. Concentrations of MTCS ranged from 0.0056 to 5.6ng/L in water, 0.01 to 0.17ng/g dry wt. in bottom sediments and 0.75 to 2.81ng/g dry wt. in SPM. These concentrations are below predicted no-effect concentrations (PNEC). Principal components analysis (PCA) results showed that synthetic musk concentrations were positively correlated, indicating common source emissions. Rainfall amount and land-use index were found to be key determinants of hydrophobic organic contaminant concentrations in this catchment. Concentrations of TCS and its methylated degradation product, MTCS, were also positively correlated. However, the relative composition of MTCS to total triclosans was relatively low in water (2.8±2.5%) and bottom sediments (0.3±0.1%), suggesting only minor transformation of TCS to MTCS. The organic carbon-water distribution ratio, log K (observed), ranged between 3.8 and 5.4 for musks, TCS and MTCS, indicating relatively strong partitioning from dissolved to solid phases. These field-derived log K (observed) values are comparable to estimated values based on physicochemical properties. The results provide insight into the occurrence, transport pathways and exposure risks of synthetic musks, triclosan and methyl triclosan in this tropical catchment.
本研究对新加坡热带城市集水区的地表水、悬浮颗粒物（SPM）和底泥中的合成麝香、三氯生（TCS）和甲基三氯生（MTCS）进行了为期 13 个月的综合调查。多环麝香 galaxolide（HHCB）是麝香化合物中浓度最高的，其浓度范围为地表水 5.16-42.9ng/L，沉积物 11.0-108ng/g 干重，SPM 中 44.1-81.3ng/g 干重。主要的硝基芳香麝香麝香酮的浓度范围为 0.08-6.45ng/L 的水中，0.082-0.72ng/g 干重。沉积物和 1.75-5.50ng/g 干重的 SPM。MTCS 的浓度范围为 0.0056-5.6ng/L 的水中，0.01-0.17ng/g 干重。在底部沉积物和 0.75-2.81ng/g 干重的 SPM。这些浓度低于预测无效应浓度（PNEC）。主成分分析（PCA）结果表明，合成麝香浓度呈正相关，表明有共同的排放源。研究发现，降雨量和土地利用指数是该集水区疏水性有机污染物浓度的关键决定因素。TCS 及其甲基化降解产物 MTCS 的浓度也呈正相关。然而，MTCS 与总三氯生的相对比例在水中相对较低（2.8±2.5%）和底部沉积物（0.3±0.1%），表明 TCS 向 MTCS 的转化较小。三氯生和 MTCS 的有机碳-水分配系数，log K（实测）范围为 3.8-5.4，表明它们从溶解相到固相的分配较强。这些现场得出的 log K（实测）值与基于物理化学性质的估计值相当。研究结果为了解热带集水区合成麝香、三氯生和甲基三氯生的存在、迁移途径和暴露风险提供了依据。
