Sun Xueli, Davis Allen P
Department of Civil and Environmental Engineering, University of Maryland, College Park, MD 20742, USA.
Chemosphere. 2007 Jan;66(9):1601-9. doi: 10.1016/j.chemosphere.2006.08.013. Epub 2006 Sep 26.
Key to managing heavy metals in bioretention is to understand their fates in bioretention facilities. In this study, pot prototypes filled with bioretention media were built to simulate the conditions of natural growth of plants. Synthetic runoff with different heavy metal loadings (copper, cadmium, lead, and zinc) was periodically applied. Metal accumulations in tissues of grasses -Panicum virgatum, Kentucky-31, and Bromus ciliatus, were investigated after 230d of growth and multiple runoff treatment events. After 183d of periodic runoff application, the concentrations of Zn, Cu, Pb and Cd with low and high loadings had the same trends in the plant tissues, Zn>Cu>Pb>Cd, following the trend of the input metal concentrations. The fates of input metals were 88-97% captured in soil media, 2.0-11.6% not captured by bioretention media, and 0.5-3.3% accumulated in plants. Compared to the metals retained by the soil, the percentages of input metals taken up by plants were relatively low due to the low plant biomass produced in this study. Greater biomass density would be required for the vegetation to have a valuable impact in prolonging the lifetime of a bioretention cell.
生物滞留池中重金属管理的关键在于了解它们在生物滞留设施中的归宿。在本研究中，构建了填充生物滞留介质的盆栽原型，以模拟植物自然生长的条件。定期施加不同重金属负荷（铜、镉、铅和锌）的合成径流。在生长230天并经过多次径流处理后，研究了草（柳枝稷、肯塔基31和纤毛雀麦）组织中的金属积累情况。在定期施加径流183天后，低负荷和高负荷的锌、铜、铅和镉在植物组织中的浓度具有相同趋势，即Zn>Cu>Pb>Cd，与输入金属浓度的趋势一致。输入金属的归宿是88 - 97%被土壤介质捕获，2.0 - 11.6%未被生物滞留介质捕获，0.5 - 3.3%积累在植物中。与土壤中保留的金属相比，由于本研究中植物生物量较低，植物吸收的输入金属百分比相对较低。植被需要更高的生物量密度才能对延长生物滞留池的使用寿命产生有价值的影响。
