| Field trials and laboratory studies have shown that the passive sampling device, polar organic chemical integrative sampler (POCIS) is suitable for monitoring aquatic contaminants in surface waters, and especially the rapidly changing nearshore environment. In the present study, the influences of environmental variables, such as water temperature, water flow rate, pH, etc. on the sampling rates (RS) of POCIS uptake were investigated using both experimental approaches in the laboratory and field trials. In studies in an environmental chamber using a static system, the RS ranged from 0.07 to 2.46 Lid across a temperature range of 5-25 °C for 30 model compounds. The RS increased with water temperature, but the differences were relatively small " 2-fold increase) for most of the model compounds. In similar static experiments conducted at pH 3, 7 and 9, the RS were maximized at the pH where the majority of the model compound is present in its neutral form, but once again, these differences were relatively small. The sampling rates for the model compounds were positively correlated with effective log octanol-water distribution coefficient (log D). The levels of dissolved organic matter in water appeared to have little effect on uptake by POCIS. To evaluate the influence of water flow on RS, a field experiment was conducted with POCIS deployed in channel systems through which treated sewage effluent flowed at rates between 2.6 and 37 cm/s. The uptake of model contaminants into POCIS increased with flow rate, but these effects were relatively small (i.e. < 2-fold) for most of the test compounds. Overall, the environmental factors tested had a relatively small influence on accumulation into POCIS. In field studies conducted in the Great Lakes, the estimated concentrations of PPCPs and EDS in the near shore zone of Lake Ontario and Lake Erie determined using POCIS were consistent with the concentrations measured with conventional spot sampling in surface water. The uptake efficiency of the pesticide-POCIS configuration is higher than that of pharmaceutical-POCIS configuration, but the pharmaceutical-POCIS accumulates a wider range of model compounds and has practical advantages for monitoring purposes. These field trials demonstrated that POCIS are suitable for long-term monitoring of organic contaminants in surface waters.;Key words: Polar organic chemical integrative sampler (POCIS), Passive sampling, Pharmaceuticals and personal care products, Endocrine disrupting substances, Great Lakes... |
