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

There is a basic lack of information about the presence of pesticide residu es 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 resi dues. These were collected at three separate sites (La Lima, Zamorano and C holuteca), each characterized by differing agricultural production systems. The main pesticide residues found in soil samples were dieldrin and p,p'-D DT, while river water samples were found to have detectable levels of hepta chlor, endosulfan and chlorpyrifos, with lagoon and well water also being s hown 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 inten sive agricultural production. The fewest pesticides with lowest concentrati ons were found in the small sub-watershed associated with traditional agric ultural 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 lag oon and well water samples more pesticides, but mostly in lower concentrati ons were detected at the traditional production site than at the others. Te n pesticide compounds were detected in fish tissue, mainly organochlorines, some of which were also found in lagoon sediments. In terms of food produc ts, almost no pesticides were detected in vegetables, but the kidney adipos e tissue taken from slaughtered cows was shown to have a tendency to contai n some organochlorines. Spring water in the traditional agricultural produc tion zone contained three organochlorine compounds as well as chlorpyrifos, but these were detected only in the rainy season. This study indicates tha t pesticide residues are present and strongly associated with areas of inte nsive agriculture, although even in the areas practicing more traditional a griculture, pesticide residues were not absent. Further pesticide monitorin g is necessary to obtain a more complete picture of the situation and based on this data an effective policy framework to assist in minimizing pestici de residue accumulation may be developed to reduce the adverse impact these compounds are known to have on the environment and human health. This snap shot 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 righ ts reserved.