Water quality and macroinvertebrate community response following pesticide applications in a banana plantation, Limon, Costa Rica Luisa Eugenia Castillo a,b,c, ⁎ , Eduardo Martínez a , Clemens Ruepert a , Candida Savage c,f , Michael Gilek c,d , Margareth Pinnock a , Efrain Solis e a Central American Institute for Studies on Toxic Substances (IRET), Universidad Nacional, Heredia, Costa Rica b Department of Research, Universidad Nacional, Heredia, Costa Rica c Department of Systems Ecology, Stockholm University, SE-106 91 Stockholm, Sweden d Sodertorns University College, Box 4101, S-141 04 Huddinge, Sweden e School of Chemistry, Universidad Nacional, Heredia, Costa Rica f Department of Marine Science, University of Otago, PO Box 56, Dunedin, New Zealand Received 18 October 2005; received in revised form 24 February 2006; accepted 26 February 2006 Available online 27 April 2006 Abstract Pesticides used in banana production may enter watercourses and pose ecological risks for aquatic ecosystems. The occurrence and effects of pesticides in a stream draining a banana plantation was evaluated using chemical characterization, toxicity testing and macrobenthic community composition. All nematicides studied were detected in the surface waters of the banana plantation during application periods, with peak concentrations following applications. Toxicity tests were limited to the carbofuran application and no toxicity was observed with the acute tests used. However, since pesticide concentrations were generally below the lowest LC50 value for crustaceans but above calculated aquatic quality criteria, there remains a risk of chronic toxicity. Accurate ecological assessments of pesticide use in banana plantations are currently limited by the lack of local short-term chronic toxicity tests and tests using sensitive native species. Relatively constant levels of four pesticides (imazalil, thiabendazole, chlorpyrifos and propiconazole), which had toxic effects according to the 96h hydra and 21d daphnia chronic test, were recorded in the effluent of the packing plant throughout the study, indicating that the solid waste trap used in this facility was not effective in eliminating toxic chemicals. Certain taxa, such as Heterelmis sp. (Elmidae), Heteragrion sp. (Megapodagrionidae, Odonata), Caenis sp. (Caenidae, Ephemerotera), and Smicridea sp. (Hidropsychidae, Trichoptera), were more abundant at reference sites than in the banana farm waters, and may be good candidates for toxicity testing. Multivariate analyses of the macroinvertebrate communities clearly showed that the banana plantation sites were significantly different from the reference sites. Moreover, following the pesticide applications, all the banana plantation sites showed significant changes in community composition, with the same genera being affected at all sites and for all pesticides (terbufos, cadusafos and carbofuran). Consequently, the results presented here show that multivariate analysis of community composition was more sensitive in distinguishing pesticide effects than the toxicity tests and richness and composition measures used. We conclude that monitoring macroinvertebrate communities can be a powerful tool in the assessment of ecological effects of banana production. © 2006 Elsevier B.V. All rights reserved. Keywords: Pesticides; Banana plantations; Aquatic ecosystems; Toxicity tests; Macroinvertebrates; Multivariate analysis Science of the Total Environment 367 (2006) 418 – 432 www.elsevier.com/locate/scitotenv ⁎ Corresponding author. Tel.: +506 238 0696. E-mail address: lcastill@una.ac.cr (L.E. Castillo). 0048-9697/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2006.02.052