Pesticide residue assessment in three selected agricultural production systems in the Choluteca River Basin of Honduras

摘要

There is a basic lack of information about the presence of pesticide residues in the environment in Central America. Over the period of February 1995 to June 1997, river, well, lagoon and spring water samples, as well as soil, fish tissue, lagoon bed sediments and some foodstuffs were taken from the greater Cholutecan River Basin of Honduras and analyzed for pesticide residues. These were collected at three separate sites (La Lima, Zamorano and Choluteca), each characterized by differing agricultural production systems. The main pesticide residues found in soil samples were dieldrin and p,p'-DDT, while river water samples were found to have detectable levels of heptachlor, endosulfan and chlorpyrifos, with lagoon and well water also being shown to contain heptachlor. These pesticides detected were in more than 20 of the samples assessed. In river water samples more pesticide residues at higher concentrations were found to be associated with areas of more intensive agricultural production. The fewest pesticides with lowest concentrations were found in the small sub-watershed associated with traditional agricultural production. Although the pesticides found in the soils at the three sites were generally similar they tended to be higher in the southern part of the Cholutecan watershed, followed by the central zone, with the lowest concentrations being found in the more traditional production zone. In lagoon and well water samples more pesticides, but mostly in lower concentrations were detected at the traditional production site than at the others. Ten pesticide compounds were detected in fish tissue, mainly organochlorines, some of which were also found in lagoon sediments. In terms of food products, almost no pesticides were detected in vegetables, but the kidney adipose tissue taken from slaughtered cows was shown to have a tendency to contain some organochlorines. Spring water in the traditional agricultural production zone contained three organochlorine compounds as well as chlorpyrifos, but these were detected only in the rainy season. This study indicates that pesticide residues are present and strongly associated with areas of intensive agriculture, although even in the areas practicing more traditional agriculture, pesticide residues were not absent. Further pesticide monitoring is necessary to obtain a more complete picture of the situation and based on this data an effective policy framework to assist in minimizing pesticide residue accumulation may be developed to reduce the adverse impact these compounds are known to have on the environment and human health. This snapshot of the pesticide distribution in three agriculturally distinct regions within the Choluteca watershed indicates that the situation is stable, but should be monitored to determine if pesticides residues will pose a health hazard in the future. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. References: 17