Silicone rubber as a passive sampler for semivolatile contaminants of indoor air
Lenka Sedlačková, Foppe Smedes, Lisa Melymuk, Roman Prokeš, Branislav Vrana
Semivolatile organic compounds (SVOCs) are mostly man-made chemicals that distribute
between the gas and solid phase. Many of them could pose a danger to people exposed to them,
and therefore it is important to monitor their concentrations to evaluate the related risks. The
gaseous concentrations obtained by passive sampling are an important parameter to assess
inhalation exposure in the indoor environment. . In this study, we employed silicone rubber (SR)
polymer as a passive sampler for monitoring of polyaromatic hydrocarbons (PAHs),
polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated
diphenyl ethers (PBDEs) in indoor air. It is assumed that silicone rubber samples contaminants
mainly from the gaseous phase. We performed a sampler calibration study in which 16 samplers
constructed from 0.5 mm thick SR sheets with a surface area of 300 cm2 each were exposed to
indoor air in a university lecture theatre for up to 56 days and 2 samplers were collected every
week. In addition to measurement of the uptake kinetics of listed compounds during exposure,
the release kinetics of performance reference compounds (PRCs) that were dosed to the
samplers prior to exposure was studied. The PRCs – PCBs not occurring in industrial mixtures covered
a broad range in volatility and, consequently, SR-air partition coefficients. The study
allowed proposing a model that can be used to estimate air sampling rate (RS in m3/day) as a
function of compounds’ molecular mass. Applying the model, we determined concentration of
contaminants in air from passive sampling uptake. These concentrations were compared to data
from low-volume active air sampler that ran simultaneously during the entire study.
Concentrations measured by passive and active sampling were in good agreement for PCBs and
OCPs, whereas in case of PBDEs and PAHs, passive samplers showed lower detection limits.
keywords:
semivolatile organic compounds, passive sampling, silicone rubber, performance reference
compounds, sampler calibration