An ecological risk assessment of pesticides and fish kills in the Sixaola watershed, Costa Rica

Beth Polidoro, Matthew J. Morra

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Along the southeastern coast of Costa Rica, a variety of pesticides are intensively applied to produce export-quality plantains and bananas. In this region, and in other agricultural areas, fish kills are often documented by local residents and/or in the national news. This study examines principal exposure pathways, measured environmental concentrations, and selected toxicity thresholds of the three most prevalent pesticides (chlorpyrifos, terbufos, and difenoconazole) to construct a deterministic risk assessment for fish mortality. Comparisons of observed pesticide concentrations, along with estimated biological effects and observations during actual fish kills, highlight gaps in knowledge in correlating pesticide environmental concentration and toxicity in tropical environments. Observations of fish kill events and measured pesticide concentrations in the field, along with other water quality indicators, suggest that a number of environmental conditions can interact to cause fish mortality and that current species toxicity datasets may not be applicable for estimating toxicological or other synergistic effects, especially in tropical environments.

Original languageEnglish (US)
Pages (from-to)5983-5991
Number of pages9
JournalEnvironmental Science and Pollution Research
Issue number6
StatePublished - Mar 1 2016


  • Bananas
  • Chlorpyrifos
  • Hazard quotient
  • Latin America
  • Toxicology
  • Water quality

ASJC Scopus subject areas

  • Environmental Chemistry
  • Pollution
  • Health, Toxicology and Mutagenesis


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