Pesticide sequestration in passive samplers (SPMDs): Considerations for deployment time, biofouling, and stream flow in a tropical watershed

Beth A. Polidoro, Matthew J. Morra, Clemens Ruepert, Luisa Eugenia Castillo

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Semi-permeable membrane devices (SPMDs) provide an informative and cost-effective approach for monitoring contaminants in remote tropical streams. Estimation and interpretation of contaminant concentrations in streams derived from SPMDs can vary based on a number of environmental factors, including stream flow, biofouling, and deployment time. In three one-month long trials, SPMDs were concurrently deployed for 4, 15, and 28 days at three stream sites in an extensive agricultural area of southeastern Costa Rica. Water, bottom sediment, and suspended solids grab samples were also collected and several environmental variables were monitored at corresponding time intervals during each month-long study period. At all three sites, SPMD concentrations of the widely used insecticide chlorpyrifos increased with deployment time, with no relationship between SPMD biofouling and pesticide sequestration. Differences in SPMD chlorpyrifos sequestration among sites are likely due to differences in stream chlorpyrifos concentration rather than differences in SPMD sampling rates. The longer exposure period of SPMDs allowed for the detection of lower concentrations of chlorpyrifos, terbufos, and difenoconazole compared to water grab samples. In addition to the use of appropriate performance reference compounds (PRCs), other environmental variables such as stream turbidity, flow regime, stream morphology, and knowledge of pesticide application methods are important considerations for optimizing SPMD deployment and data interpretation in tropical regions.

Original languageEnglish (US)
Pages (from-to)1866-1874
Number of pages9
JournalJournal of Environmental Monitoring
Issue number10
StatePublished - Dec 1 2009
Externally publishedYes

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Management, Monitoring, Policy and Law


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