深圳大学学报理工版

为探索城市道路雨水的生物毒性,保证雨水回用的安全性,以道路雨水径流对蛋白核小球藻的毒性为例,综合解析道路雨水径流的毒性水平及其主要影响因素,探究毒性作为安全性评价指标的适宜性.通过对深圳市12条典型道路进行原位模拟道路雨水径流样品的采集和检测发现,城市路面累积的颗粒物负荷与其表面附着的重金属和总有机碳负荷并不呈现正相关.而从道路雨水径流对蛋白核小球藻的毒性来看,颗粒物、重金属以及总有机碳的负荷与表现出的毒性也没有呈明显正相关,证实了传统的海绵城市雨水回用研究中以某种(类)污染物为主要关注点的研究方法是不合适的,应将多种污染物联合表达出的毒性作为指征雨水径流能否安全回用的重要指标.另外,通过主成分分析发现,道路周边工业区用地类型是影响城市雨水径流毒性的最主要因素.相比有机污染物,重金属对城市雨水径流的毒性贡献更大.因此,在海绵城市建设中,应该根据不同的回用目标,遵循“低质低用、高质高用”的原则,对毒性较高的雨水径流进行适宜性回用,同时应更关注重金属的去除.

In order to explore the biological toxicity of urban road stormwater runoff and hence ensure its reuse safety, we comprehensively analyze the toxicity level and the main influential factors of road stormwater runoff. By using Chlorella pyrenoidasa as a case study, we explore the toxicity adequacy as a parameter for the stormwater reuse safety assessment. We collect the in-situ simulated runoff samples from twelve typical urban roads in Shenzhen. The results show that deposited sediment load(TS)on urban road surface is not positively correlated with the heavy metal(HM)and total organic carbon(TOC)load attached to the surface. The toxicity of road rainwater runoff to Chlorella pyrenoidasa is not closely related to TS, HM and TOC loads. These results confirm that tranditional sponge city rainwater recycling approach for investigating stormwater quality based on particular pollutants is not appropriate. Instead, the combined toxicity given by all pollutants is a preferred option in terms of indicating whether the road stormwater can be reused safely in the process of sponge city construction. According to principal component analysis(PCA)results, industrial areas significantly contribute to the stormwater toxicity compared to other factors. Additionally, heavy metals could contribute more to the toxicity than organic matters. This implies that in sponge city construction, it is important to appropriately reuse stormwater with high toxicity based on the “fit for purposes” theory, as well as paying more attention to the removal of heavy metals.