Accumulation of Current-Use Pesticides in Neotropical Montane Forests

Abstract

In Central America, chemical-intensive tropical agriculture takes place in close proximity to highly valued and biologically diverse ecosystems, yet the potential for atmospheric transport of pesticides from plantations to national parks and other reserves is poorly characterized. The specific meteorological conditions of mountain ranges can lead to contaminant convergence at high altitudes, raising particular concern for montane forest ecosystems downwind from pesticide use areas. Here we show, based on a wide-ranging air and soil sampling campaign across Costa Rica, that soils in some neotropical montane forests indeed display much higher concentrations of currently used pesticides than soils elsewhere in the country. Specifically, elevated concentrations of the fungicide chlorothalonil, the herbicide dacthal, and the insecticide metabolite endosulfan sulfate on volcanoes Barva and Poas, lying directly downwind of the extensive banana plantations of the Caribbean lowland, indicate the occurrence of atmospheric transport and wet deposition of pesticides at high altitudes. Calculations with a contaminant fate model, designed for mountain regions and parametrized to the Costa Rican environment, show that chemicals with a log K(AW) between -3 and -5 have a greater potential for accumulation at high altitudes. This enrichment behavior is quantified by the Mountain Contamination Potential and is sensitive to contaminant degradability. The modeling work supports the hypothesis suggested by the field results that it is enhanced precipitation scavenging at high elevations (caused by lower temperatures and governed by K(AW)) that causes pesticides to accumulate in tropical montane areas. By providing for the first time evidence of significant transfer of currently used pesticides to Central American montane cloud forests, this study highlights the need to evaluate the risk that tropical agricultural practices place on the region's ecological reserves.

Environmental fate and behavior of persistent organic pollutants in Shergyla Mountain, southeast of the Tibetan Plateau of China

“…Current application status, volatilization from underlying surface, enhanced gas and particle scavenging caused by increased precipitation at higher elevations should, to some extent, jointly accounted for the different distributions of these POPs in the atmosphere of the western slope of the Shergyla Mountain. Since DDTs Davidson et al, 2003;Shen et al, 2005) and endosulfan (Daly et al, 2007;Wania and Westgate, 2008) are particularly susceptible to mountain cold-trapping, the trend of increasing air concentrations of DDTs and endosulfans with altitude in the present work may reflect the re-volatilization of DDTs and endosulfans that had been cold-trapped at high mountain areas. The higher regression slope of 2,4 0 -DDT than the one of 4,4 0 -DDT indicated 2,4 0 -DDT exhibit higher potential of partitioning in colder condition experienced with altitude.…”

Temporal and spatial variation of atmospherically deposited organic contaminants at high elevation in yosemite national park, California, USA

“…Ranges that lie in close proximity and downwind from areas of high population density, intense agriculture, or intense industrial activity, such as the European Alps, the southern slope of the Himalayas, the Sierra Nevada of California, USA, and the mountains of Costa Rica may be particularly vulnerable [2,3]. The present study focuses on the Sierra Nevada mountain range, which lies adjacent to one of the highest agricultural pesticide-use areas in North America, the Central Valley of California [4].…”

Toxicity of the organophosphate pesticide diazinon to crayfish of differing age

“…The most common type, especially in aquatic environments, is the pesticide. Aquatic habitats throughout the world are contaminated with at least one pesticide, and commonly with complex mixtures including, e.g., atrazine, chlorpyrifos, diazinon, and malathion (Battaglin et al 2003;Daly et al 2007;Banaee et al 2011).…”