Jayarathne Ayomi, Egodawatta Prasanna, Ayoko Godwin A, Goonetilleke Ashantha
Science and Engineering Faculty, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, 4001, Queensland, Australia.
Environ Pollut. 2017 Nov;230:218-226. doi: 10.1016/j.envpol.2017.06.059. Epub 2017 Jun 24.
Detailed knowledge of the processes that metals undergo during dry weather periods whilst deposited on urban surfaces and their environmental significance is essential to predict the potential influence of metals on stormwater quality in order to develop appropriate stormwater pollution mitigation measures. However, very limited research has been undertaken in this area. Accordingly, this study investigated the geochemical phase and particle size relationships of seven metals which are commonly associated with urban road dust, using sequential extraction in order to assess their mobility characteristics. Metals in the sequentially extracted fractions of exchangeable, reducible, oxidisable and residual were found to follow a similar trend for different land uses even though they had variable accumulation loads. The high affinity of Cd and Zn for exchangeable reactions in both, bulk and size-fractionated solid samples confirmed their high mobility, while the significant enrichment of Ni and Cr in the stable residual fraction indicated a low risk of mobility. The study results also confirmed the availability of Cu, Pb and Mn in both, stable and mobile fractions. The fine fraction of solids (<150 μm) and antecedent dry days can be highlighted as important parameters when determining the fate of metals associated with urban road dust. The outcomes from this study are expected to contribute to the development of effective stormwater pollution mitigation strategies by taking into consideration the metal-particulate relationships.
详细了解金属在干燥天气期间沉积在城市表面时所经历的过程及其环境意义，对于预测金属对雨水水质的潜在影响从而制定适当的雨水污染缓解措施至关重要。然而，该领域的研究非常有限。因此，本研究利用顺序萃取法研究了七种通常与城市道路灰尘相关的金属的地球化学相和粒径关系，以评估它们的迁移特性。尽管不同土地利用类型的金属累积负荷不同，但在可交换态、可还原态、可氧化态和残渣态的顺序萃取组分中，金属呈现出相似的趋势。在整体和粒径分级的固体样品中，镉和锌对可交换反应的高亲和力证实了它们的高迁移性，而镍和铬在稳定残渣态中的显著富集表明其迁移风险较低。研究结果还证实了铜、铅和锰在稳定态和可移动态组分中的有效性。在确定与城市道路灰尘相关的金属归宿时，固体细颗粒部分（<150μm）和前期干旱天数可被视为重要参数。本研究结果有望通过考虑金属与颗粒物的关系，为制定有效的雨水污染缓解策略做出贡献。
