title: Current-use pesticide transport to Costa Rica's high-altitude tropical cloud forest.
abstract: To gain insight into the atmospheric transport and deposition of organic contaminants in high-altitude forests in the humid tropics, pesticides were analyzed in air, water, and soil samples from Costa Rica. Passive samplers deployed across the country revealed annually averaged air concentrations of chlorothalonil, endosulfan, and pendimethalin that were higher in areas with intensive agricultural activities than in more remote areas. Atmospheric concentrations were particularly high in the intensively cultivated central valley. Only endosulfan and its degradation products were found in soils sampled along an altitudinal transect on the northern side of Volcano Turrialba, which is facing heavily cultivated coastal plains. Consistent with calculations of cold trapping in tropical mountains, concentrations of endosulfan sulfate increased with altitude. Pesticide levels in lake, creek, fog, and arboreal water samples from high-elevation cloud forests were generally below 10 ng · L(-1). Endosulfan sulfate was the most abundant pesticide in water, with concentrations ranging from 0.4 to 9.4 ng · L(-1). Its levels were highest in water sampled from bromeliads. Levels of total endosulfan in water are much lower than the reported median lethal concentration (LC50) value for acute toxicity of α-endosulfan to tadpoles. Although this suggests that the presence of pesticide might not have a direct impact on amphibian populations, the possibility of effects of chronic exposure to a mixture of substances cannot be excluded. Fog was relatively enriched in some of the analyzed pesticides, such as dacthal and chlorothalonil, and may constitute an important deposition pathway to high-altitude tropical cloud forest.
authors: Department of Chemistry, University of Toronto Scarborough, Toronto, Ontario, Canada.
authors: Chubashini
authors: C
authors: Shunthirasingham
authors: Todd
authors: T
authors: Gouin
authors: Ying D
authors: YD
authors: Lei
authors: Clemens
authors: C
authors: Ruepert
authors: Luisa E
authors: LE
authors: Castillo
authors: Frank
authors: F
authors: Wania
mesh_terms: D000383:Agriculture / Q000706:statistics & numerical data; D000531:Altitude; D003364:Costa Rica; D004726:Endosulfan / Q000032:analysis; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis*; D004787:Environmental Pollution / Q000706:statistics & numerical data; D005618:Fresh Water / Q000737:chemistry; D010575:Pesticides / Q000032:analysis*; D010795:Phthalic Acids / Q000032:analysis; D012987:Soil / Q000737:chemistry; D014197:Trees
chemical_list: D004785:Environmental Pollutants; D010575:Pesticides; D010795:Phthalic Acids; D012987:Soil; C007220:dimethyl 2,3,5,6-tetrachloroterephthalate; D004726:Endosulfan