Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL, 32611 - 6450, USA.
Department of Civil, Architectural and Environmental Engineering, University of Miami, P.O. Box 248294, Coral Gables, FL, 33146 - 0630, USA.
Environ Pollut. 2018 Nov;242(Pt B):1198-1205. doi: 10.1016/j.envpol.2018.07.134. Epub 2018 Aug 2.
A limitation to recycling wood from construction and demolition (C&D) waste is contamination of metals from the inadvertent inclusion of preservative treated wood, in particular wood treated with chromated copper arsenate (CCA) and newer copper-based formulations. To minimize contamination many regions have developed best management practices (BMPs) for separating treated from untreated wood. The objective of this study was to evaluate the fraction of preservative treated wood in recycled C&D wood after the implementation of BMPs, using Florida as a case study. Methods involved collecting recycled C&D wood samples from throughout the state, measuring metals concentrations (As, Cu, and Cr) in the samples to compute the fraction of recycled wood treated with waterborne wood preservatives, and comparing measurements with those taken prior to the formalization of BMPs. Metals concentrations were measured using two methods, one based on traditional laboratory digestion methods and another using a more rapid hand-held X-ray Fluorescence (XRF) device in the field. The proportion of waterborne preservative-treated wood in recycled wood products has reduced significantly in the intervening 20 years (from 6% to 2.9%), and the fraction of CCA-treated wood has been reduced even further, to 1.4%. The remaining fraction of waterborne preservative-treated wood is comprised of new formulations of copper-based preservatives. This suggests that restrictions from the wood preservation industry and best management practices implemented at recycling facilities have been effective in reducing heavy metal contamination from pressure treated lumber in recycled wood products.
回收建筑和拆除（C&D）废物中的木材存在一个限制，即由于无意中包含了经防腐剂处理的木材，特别是用铬酸铜砷酸盐（CCA）和更新的铜基配方处理的木材，会导致金属污染。为了最大程度地减少污染，许多地区已经制定了最佳管理实践（BMPs），以将处理过的木材与未处理的木材分开。本研究的目的是评估在实施 BMPs 后，经防腐剂处理的木材在回收的 C&D 木材中的比例，以佛罗里达州为例。方法包括从全州范围内收集回收的 C&D 木材样本，测量样本中的金属浓度（As、Cu 和 Cr），以计算经水性木材防腐剂处理的回收木材的比例，并将测量结果与 BMPs 正式实施前的测量结果进行比较。金属浓度使用两种方法进行测量，一种基于传统的实验室消化方法，另一种在现场使用更快速的手持式 X 射线荧光（XRF）设备。在这 20 年的时间里，回收木材产品中经水性防腐剂处理的木材的比例显著降低（从 6%降至 2.9%），CCA 处理的木材比例甚至进一步降低，至 1.4%。剩余的水性防腐剂处理木材的比例由新型铜基防腐剂配方组成。这表明木材防腐行业的限制以及回收设施实施的最佳管理实践在减少回收木材产品中压力处理木材的重金属污染方面已取得成效。
