The Potential Influence of Forests and Climate Change on the Environmental Fates of Organic Compounds in Tropical Watersheds

This exploratory review synthesizes current knowledge on the use, exposures and environmental fates of PBDEs, dioxins and dioxin-like chemicals, and current-use pesticides, as well as purports the potential for forests and climate change to affect their fates at the catchment scale in tropical regions. Organic compounds such as these are under global scrutiny because of their widespread distribution and potential for adverse health impacts. PBDEs and current-use pesticides are produced for their beneficial services as flame retardants and pest controls, respectively, whereas dioxins and furans are the by-products of combustion events involving many organic compounds. However, these chemicals distribute to various environmental media and are associated with adverse health effects, including neurotoxicity and carcinogenicity. Previous studies have shown that temperate and boreal forests influence the environmental fates of some organic chemicals by transferring them from the atmosphere to the soils, therefore potentially reducing atmospheric exposure. Changing climate variables, such as temperature change, are also expected to be important in the environmental distribution of organic contaminants. However, the effect of these factors, forests and climate change, on the environmental fates of organic pollutants in tropical watersheds have not been adequately examined. Knowledge of the fates and impacts of organic pollutants in tropical regions is critical for environmental management and policy development therein, and this review therefore explores the potential influences of forests and climate change on contaminant fates in tropical regions. Finally, the areas where more research is needed to assist in these endeavors are elucidated.