Unbiased Passive Sampling of All Polychlorinated Biphenyls Congeners from Air

The desire to quantify the presence of a wide range of
polychlorinated
biphenyls (PCBs) in air is driven both by an interest in the sources
and fate of unintentionally produced congeners and in quantifying
human inhalation exposure to volatile PCBs. The wide volatility range
can introduce bias when sampling the entire suite of PCBs. Here, we
present the result of a field calibration experiment that demonstrates
that even the most volatile PCBs maintain linear uptake in a passive
air sampler using XAD-resin as the sorbent (XAD-PAS). Empirically
derived sampling rates (SRs) for 66 congeners decrease
with the number of chlorines and, within a homologue, increase with
the number of chlorines in the ortho-position. The large seasonal
temperature range at the site of the calibration allowed for an estimation
of the temperature dependence of the SRs. The effects
of chlorine substitution and temperature can be expressed quantitatively
through a regression relating the SR to the sorption
constant to XAD from the gas phase. As a result, it is possible to
estimate SRs for all congeners at any deployment
temperature. The XAD-PAS is well suited for unbiased sampling of gaseous
PCBs in a wide variety of settings.