title: Results from the Lake Michigan Mass Balance study: concentrations and fluxes of atmospheric polychlorinated biphenyls and trans-nonachlor.
abstract: In this paper, we summarize the data and methods used to estimate atmospheric exchange of polychlorinated biphenyls (PCBs) and trans-nonachlor with Lake Michigan. This work was conducted as part of the Lake Michigan Mass Balance (LMMB) study. For the atmospheric component of the LMMB, more than 400 gas- and particulate-phase samples were collected at eight sites on the shore around the lake (shoreline) and at 14 sites on the lake (over-water). We review the quality of the data set; describe the concentrations in atmospheric gas and particulate phases; report local, instantaneous, net gas fluxes; and estimate annual deposition of the particle-associated compounds. The quality of the data set is high except for a subset of over-water samples where PCB contamination is suspected. Gas-phase trans-nonachlor concentrations (although not the resulting gas fluxes) are inversely correlated with latitude and positively correlated with temperature. Gas-phase sigmaPCBs (sum of 98 congener groups) are highest in concentration at the Chicago site and lowest at the Sleeping Bear Dunes site. The resulting sigmaPCB gas fluxes exhibit a seasonality that reflects elevated summertime gas-phase concentrations not compensated by temperature-corrected Henry's law coefficients. Particulate-phase deposition is much smaller in magnitude than gas fluxes, for either compound. Gas and particulate fluxes are comparable only at the Chicago site and only when large (> 10 microm) particulates are considered.
authors.affiliation: Department of Civil and Environmental Engineering, The University of Iowa, Iowa City 52242, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Miller
authors.forename: M L
authors.initials: ML
authors.lastname: Green
authors.forename: J V
authors.initials: JV
authors.lastname: Depinto
authors.forename: K C
authors.initials: KC
authors.lastname: Hornbuckle
mesh_terms: D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D007087:Illinois; D011078:Polychlorinated Biphenyls / Q000737:chemistry*
chemical_list: D006843:Hydrocarbons, Chlorinated; C001870:nonachlor; D011078:Polychlorinated Biphenyls