Manually grab or automated water sampling devices have traditionally been used to collect surface water samples for chemical analysis. Recently, passive sampling devices such as POCIS (Polar Organic Chemical Integrative Sampler) and SPMD (Semi Permeable Membrane Device) have been introduced to allow in-situ collection of hydrophilic and hydrophobic chemicals in streams and rivers. We explored the utility of POCIS as a more economical alternative to traditional sampling methods. However, a limitation of POCIS in field settings is the dependence of sampling rate on environmental parameters such as hydrodynamic conditions and temperature. In this study, two 10-point, 21-day calibration experiments were carried out to investigate the effects of changing hydrodynamic conditions (ranging from static to flow rate of up to 20 cm/s) and temperatures (ranging from 8 to 39 °C) on POCIS sampling rates for 12 crop protection chemicals. Exposure concentration was held constant in each experiment. For temperatures ranging from 8 to 39 °C, there was a linear response in POCIS sampling rates (R<sup>2</sup>=0.865-0.996). Sampling rate response for most compounds was essentially flat for all flow velocities (5-20 cm/s) tested in our study when temperature was held constant. Observed temperature effects on sampling rate were most pronounced for compounds with log K<sub>ow</sub> ranging from 2 to 4. Results increase our understanding of the effects of environmentally relevant parameters on POCIS sampling rates and provide insight on how to account for these parameters when calculating POCIS field sampling rates derived from laboratory studies.

Monitoring of crop protection chemicals in water: Effects of changing environmental conditions on POCIS sampling rates

255th National Meeting (2018)

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