Arsenic leaching from mulch made from recycled construction and demolition wood and impacts of iron-oxide colorants
Arsenic leaching from mulch made from recycled construction and demolition wood and impacts of iron-oxide colorants
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DOI：
10.1021/es060623y
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发表时间：
2006-08-15
影响因子：
11.4
通讯作者：
Jacobi, Gary A., Jr.
中科院分区：
文献类型：
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作者：
Shibata, Tomoyuki;Solo-Gabriele, Helena M.;Jacobi, Gary A., Jr.
据报道，由回收的建筑和拆除（C&D）木材制成的覆盖物含有高水平的砷，这是由于无意中包含铬酸铜砷酸盐（CCA）处理的木材。这种覆盖物通常也用氧化铁着色，氧化铁是一种已知的结合砷的化合物。本研究的目的是量化的砷从覆盖由C&D木材的释放，以评估氧化铁着色剂的影响，在潜在的降低砷的浸出率，并评估其他变量对渗滤液浓度的相对意义。制备了总共3组覆盖物样品（0%、5%或100%CCA处理的木材），其中含有添加或不添加着色剂的样品。每个样品都进行了两次测试：现场浸出测试和合成沉淀浸出程序（SPLP）。结果表明，0%处理的木质覆盖物的渗滤液中砷浓度始终较低（< 0.003-0.013 mg/L），而5%和100%处理的木质覆盖物的渗滤液中砷浓度较高（5%处理的渗滤液中砷浓度为0.059-2.23 mg/L; 100%处理的渗滤液中砷浓度为0.711-22.7 mg/L）。在1年的监测期间，从现场样品中浸出的砷的质量是砷的初始质量的10%和15%之间。着色剂减少砷的浸出超过20%的现场渗滤液和50%的SPLP渗滤液，平均。然而，研究表明，这种效果可能不会持续很长时间。除了着色剂，观察到其他因素影响砷的量从污染的覆盖浸出。这些因素包括覆盖物中CCA处理过的木材的比例、时间和降雨的pH值。
Mulch made from recycled construction and demolition (C&D) wood has been reported to contain elevated levels of arsenic from inadvertent inclusion of chromated copper arsenate (CCA)-treated wood. Such mulch is also commonly colored with iron oxide, a compound known to bind arsenic. The objectives of this study were to quantify the releases of arsenic from mulch made from C&D wood, to evaluate the impacts of an iron-oxide colorant in potentially decreasing arsenic leaching rates, and to evaluate the relative significance of additional variables on leachate concentrations. A total of 3 sets of mulch samples (0%, 5%, or 100% CCA-treated wood) were prepared containing a sample either with or without colorant addition. Each sample was subjected to two tests: a field leaching test and the Synthetic Precipitation Leaching Procedure (SPLP). Results showed that arsenic concentrations in the field leachate from the 0% treated wood mulches were consistently low (< 0.003-0.013 mg/L) whereas leachates from 5 and 100% treated wood mulches were characterized by higher arsenic concentrations (0.059-2.23 mg/L for 5%; 0.711-22.7 mg/L for 100%). The mass of arsenic leached from the field samples during the 1-year monitoring period was between 10 and 15% of the initial mass of arsenic. The colorant reduced the leaching of arsenic by more than 20% for the field leachate and 50% for the SPLP leachate, on average. However, the study showed that the effect may not last for long periods. Besides colorant addition other factors were observed to affect the amount of arsenic leached from contaminated mulch. These include the proportion of CCA-treated wood in the mulch, time, and pH of rainfall.