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Elevated per- and polyfluoroalkyl substance (PFAS) concentrations have been reported in municipal solid waste (MSW) landfill leachate with higher levels in wet and warmer subtropical climates. Information about landfill leachate characteristics is much more limited in tropical climates. In this study, 20 landfill leachate samples were collected from three MSW landfills on the tropical island of Puerto Rico and results were compared against landfills nationally and within Florida, USA. The samples collected in Puerto Rico underwent physical-chemical analysis, as well as a quantitative analysis of 92 PFAS. Samples described in this study include discrete leachate types, such as leachate, gas condensate, and leachate which has undergone on-site treatment (e.g., RO treatment, phytoremediation, lagoons). A total of 51 PFAS were detected above quantitation limits, including perfluorohexylphosphonic acid, a perfluoroalkyl acid (PFAA) which has not been reported previously in landfill leachate. ∑PFAS concentrations in this study (mean: 38,000 ng L -1 ), as well as concentrations of individual PFAS, are significantly higher than other reported MSW landfill leachate concentrations. The profiles of leachates collected from on-site treatment systems indicate possible transformation of precursor PFAS as a result of treatment processes - oxidizing conditions, for example, may facilitate aerobic transformation, increase the concentrations of PFAAs, and possibly increase the apparent ∑PFAS concentration. Extreme climate events, including rising temperatures and more frequent hurricanes, have placed additional strain on the solid waste management infrastructure on the island - adding complexity to an already challenging PFAS management issue. As concern grows over PFAS contamination in drinking water, these findings should inform solid waste and leachate management decisions in order to minimize PFAS emissions in island environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

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., (Copyright © 2018 Elsevier Ltd. All rights reserved.)