Polydimethylsiloxane (silicone rubber) brooch as a personal passive air sampler for semi-volatile organic compounds.

Exposure assessments conducted using a personal sampler include the contribution of human activities to exposure that is neglected when using a stationary air sampler. This study evaluated the uptake characteristics and application of the polydimethylsiloxane (PDMS or silicone rubber) brooch as a personal passive air sampler (PPAS) for measuring concentrations of two groups of semi-volatile organic compounds (SVOCs), namely phthalates and organophosphate esters (OPEs), indoors in proximity to the breathing zone. Uptake rates of the PDMS brooch were calibrated against a personal low volume active air sampler (PLV-AAS) co-deployed on each of five study participants working in offices for 8 hs daily for four days. Sampling rates measured here ranged from 0.41 ±â€¯0.33 to 1.33 ±â€¯0.34 m3 day-1 dm-2 with an average value of 0.86 ±â€¯0.29 m3 day-1 dm-2. Personal air concentrations of 1211 to 2640 ng m-3 for ∑5 phthalates and 254 to 663 ng m-3 for ∑5 OPEs were measured for three study participants who used the PDMS brooches continuously for seven days. These concentrations resulted in estimated inhalation exposures of 19,400 to 42,400 ng day-1 for ∑5 phthalates and 4,070 to 10,600 ng day-1 for ∑5 OPEs. This study demonstrated that the PDMS brooch can be used to assess inhalation exposure when worn for at least 24 h indoors, for compounds present in >4 ng m-3 in air such as individual phthalates and OPEs tested here.

Passive air sampling of flame retardants and plasticizers in Canadian homes using PDMS, XAD-coated PDMS and PUF samplers.

Passive air samplers (PAS) were evaluated for measuring indoor concentrations of phthalates, novel brominated flame retardants (N-BFRs), polybrominated diphenyl ethers (PBDEs), and organophosphate esters (OPEs). Sampling rates were obtained from a 50-day calibration study for two newly introduced PAS, polydimethylsiloxane (PDMS) or silicone rubber PAS (one with and one without a coating of styrene divinyl benzene co-polymer, XAD) and the commonly used polyurethane foam (PUF) PAS. Average sampling rates normalized to PAS surface area were 1.5 ±â€¯1.1 m3 day-1 dm-2 for both unsheltered PDMS and XAD-PDMS, and 0.90 m3 ±â€¯0.6 day-1dm-2 for partially sheltered PUF. These values were derived based on the compound-specific sampling rates measured here and in the literature for the PAS tested, to reasonably account for site-specific variability of sampling rates. PDMS and PUF were co-deployed for three weeks in 51 homes located in Ottawa and Toronto, Canada. Duplicate PUF and PDMS samplers gave concentrations within 10% of each other. PDMS and PUF-derived air concentrations were not statistically different for gas-phase compounds. PUF had a higher detection of particle-phase compounds such as some OPEs. Phthalate and OPE air concentrations were ∼100 times higher than those of N-BFRs and PBDEs. Concentrations were not systematically related to PM10, temperature or relative humidity. We conclude that both PAS provide replicable estimates of indoor concentrations of these targeted semi-volatile organic compounds (SVOCs) over a three-week deployment period. However, PUF is advantageous for collecting a wider range of compounds including those in the particle phase.

Saltwater flotation for more efficient matrix separation of wetland macroinvertebrates does not affect total mercury or methylmercury concentrations.

The authors compared benthic wetland invertebrate matrix separation techniques (handpicking vs saltwater flotation) to test for effects on invertebrate mercury concentrations. Neither total mercury nor methylmercury concentrations differed significantly between techniques across 8 taxa. Matrix separation by the flotation technique took significantly less time and resulted in significantly greater abundance recovery in some taxa. The authors conclude that the saltwater-based flotation technique does not lead to mercury contamination or analytical interference issues.