The determination of gas phase dry deposition fluxes and mass transfer coefficients (MTCs) of polychlorinated biphenyls (PCBs) using a modified water surface sampler (WSS)

Abstract

Gas phase PCB dry deposition and concentration samples were collected simultaneously between July 2004 and May 2005 at a suburban site in Bursa, Turkey. A modified water surface sampler (WSS) was employed to collect gas phase fluxes while a high-volume air sampler (HVAS) was used for concentration samples. The WSS was able to collect both particle and gas phase PCB deposition samples. The collected PCBs on water surface were captured by a filter and an XAD-2 resin column during water cycle. The average of gas phase PCB deposition flux, determined by analyzing the XAD-2 resin column, was 79.3 +/- 40.5 ng m(-2) d(-1) and its percentage in total (gas+particle) PCB flux was about 60. The average of gas phase PCB concentration measured concurrently with flux samples was 224.4 +/- 160.2 pg m(-3) and its ratio to the total (gas+particle) PCB concentration was 85%. This difference was likely due to the different deposition characteristics of gases and particulates. Dominant PCB homolog groups were 3-4 chlorobiphenyls (CBs) for both ambient air and gas phase deposition samples. Mass transfer coefficients (MTC, K-g) for air-side were determined using gas phase flux and ambient air concentration values. The average overall K-g ranged between 0.21 and 0.96 cm.s(-1) with an average of 0.60 +/- 0.19 cm s(-1)