Rapid semi-continuous calibration and field test of membrane-enclosed silicone collector as passive water sampler

The new membrane-enclosed silicone collector (MESCO) was, in two different configurations with respect to the thickness of low-density polyethylene membrane used, subject to serial batch extraction tests to obtain (preliminary) sampling rates for estimating water concentrations of selected chlorinated organic compounds and polycyclic aromatic hydrocarbons. This rapid calibration procedure is simple to implement compared to experiments in a flow-through apparatus and yielded reasonable sampling rates in the range of 50 microL-2 mL per hour for the compounds tested. The new MESCO formats were also exposed for 28 days in the polluted creek to test their field performance. For priority contaminants of special interest, alpha-hexachlorocyclohexane and hexachlorobenzene, the time-weighted average concentrations derived from the freshly calibrated sampling devices agree well with those obtained by conventional water analysis of spot samples.