Accumulation of Current-Use Pesticides in Neotropical Montane Forests

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• 作者：Gillian L. Daly ; Ying D. Lei ; Camilla Teixeira ; Derek C. G. Muir ; Luisa E. Castillo ; Frank Wania
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：February 15, 2007
• 年：2007
• 卷：41
• 期：4
• 页码：1118 - 1123
• 全文大小：393K
• 年卷期：v.41,no.4(February 15, 2007)
• ISSN：1520-5851

文摘

In Central America, chemical-intensive tropical agriculturetakes place in close proximity to highly valued andbiologically diverse ecosystems, yet the potential foratmospheric transport of pesticides from plantations tonational parks and other reserves is poorly characterized.The specific meteorological conditions of mountainranges can lead to contaminant convergence at highaltitudes, raising particular concern for montane forestecosystems downwind from pesticide use areas. Here weshow, based on a wide-ranging air and soil samplingcampaign across Costa Rica, that soils in some neotropicalmontane forests indeed display much higher concentrationsof currently used pesticides than soils elsewhere in thecountry. Specifically, elevated concentrations of the fungicidechlorothalonil, the herbicide dacthal, and the insecticidemetabolite endosulfan sulfate on volcanoes Barva and Poas,lying directly downwind of the extensive banana plantationsof the Caribbean lowland, indicate the occurrence ofatmospheric transport and wet deposition of pesticides athigh altitudes. Calculations with a contaminant fatemodel, designed for mountain regions and parametrizedto the Costa Rican environment, show that chemicals witha log K_AW between -3 and -5 have a greater potentialfor accumulation at high altitudes. This enrichment behavioris quantified by the Mountain Contamination Potentialand is sensitive to contaminant degradability. The modelingwork supports the hypothesis suggested by the fieldresults that it is enhanced precipitation scavenging athigh elevations (caused by lower temperatures and governedby K_AW) that causes pesticides to accumulate in tropicalmontane areas. By providing for the first time evidence ofsignificant transfer of currently used pesticides toCentral American montane cloud forests, this studyhighlights the need to evaluate the risk that tropicalagricultural practices place on the region's ecologicalreserves.