University of Canterbury, Department of Civil and Natural Resources Engineering, Private Bag 4800, Christchurch, New Zealand.
University of Canterbury, Department of Civil and Natural Resources Engineering, Private Bag 4800, Christchurch, New Zealand.
Sci Total Environ. 2015 Mar 1;508:206-13. doi: 10.1016/j.scitotenv.2014.11.094. Epub 2014 Dec 5.
Atmospheric pollutants deposited on impermeable surfaces can be an important source of pollutants to stormwater runoff; however, modelling atmospheric pollutant loads in runoff has rarely been done, because of the challenges and uncertainties in monitoring their contribution. To overcome this, impermeable concrete boards (≈ 1m(2)) were deployed for 11 months in different locations within an urban area (industrial, residential and airside) throughout Christchurch, New Zealand, to capture spatially distributed atmospheric deposition loads in runoff over varying meteorological conditions. Runoff was analysed for total and dissolved Cu, Zn, Pb, and total suspended solids (TSS). Mixed-effect regression models were developed to simulate atmospheric pollutant loads in stormwater runoff. In addition, the models were used to explain the influence of different meteorological characteristics (e.g. antecedent dry days and rain depth) on pollutant build-up and wash-off dynamics. The models predicted approximately 53% to 69% of the variation in pollutant loads and were successful in predicting pollutant-load trends over time which can be useful for general stormwater planning processes. Results from the models illustrated the importance of antecedent dry days on pollutant build-up. Furthermore, results indicated that peak rainfall intensity and rain duration had a significant relationship with TSS and total Pb, whereas, rain depth had a significant relationship with total Cu and total Zn. This suggested that the pollutant speciation phase plays an important role in surface wash-off. Rain intensity and duration had a greater influence when the pollutants were predominantly in their particulate phase. Conversely, rain depth exerted a greater influence when a high fraction of the pollutants were predominantly in their dissolved phase. For all pollutants, the models were represented by a log-arctan relationship for pollutant build-up and a log-log relationship for pollutant wash-off. The modelling approach enables the site-specific relationships between individual pollutants and rainfall characteristics to be investigated.
大气污染物在不透水表面的沉积可能是雨水径流中污染物的重要来源；然而，由于监测其贡献的挑战和不确定性，很少有人对雨水径流水体中大气污染物负荷进行建模。为了克服这一困难，在新西兰克赖斯特彻奇市的不同地点（工业区、居民区和机场区）部署了不透水混凝土板（≈1m(2))，以捕获不同气象条件下雨水径流水体中空间分布的大气沉积负荷。对雨水进行了总铜、总锌、总铅和总悬浮固体（TSS）的分析。采用混合效应回归模型模拟雨水径流水体中的大气污染物负荷。此外，还利用这些模型来解释不同气象特征（如前干天数和降雨深度）对污染物积累和冲刷动力学的影响。这些模型预测了污染物负荷变化的 53%至 69%，成功地预测了随时间推移的污染物负荷趋势，这对于一般的雨水规划过程很有用。模型结果说明了前干天数对污染物积累的重要性。此外，结果表明，降雨强度峰值和降雨持续时间与 TSS 和总铅之间存在显著关系，而降雨深度与总铜和总锌之间存在显著关系。这表明在表面冲刷过程中，污染物的形态阶段起着重要作用。当污染物主要以颗粒态存在时，降雨强度和持续时间的影响更大。相反，当污染物主要以溶解态存在时，降雨深度的影响更大。对于所有污染物，模型都表示为污染物积累的对数正切关系和污染物冲刷的对数对数关系。该建模方法可以调查单个污染物与降雨特征之间的特定于地点的关系。
