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

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