The trans-Pacific and regional North American atmospheric transport of polycyclic aromatic hydrocarbons (PAHs) and pesticides in biomass burning emissions was measured in air masses from April to September 2003 at two remote sites in western North America. Mary’s Peak Observatory (MPO) is located in Oregon’s Coast Range and Cheeka Peak Observatory (CPO) is located on the tip of the Olympic Peninsula in Washington State. During this time period, both remote sites were influenced by PAH and pesticide emissions from forest fires in Siberia and regional fires in Oregon and Washington State. Concurrent samples were taken at both sites on June 2 and August 4, 2003. On these dates, CPO had elevated gas phase PAH, alpha-hexachlorocyclohexane and retene concentrations (p<0.05) and MPO had elevated retene, particulate phase PAH and levoglucosan concentrations due to trans-Pacific transport of emissions from fires in Siberia. In addition, during the April to September 2003 sampling period, CPO and MPO were influenced by emissions from regional fires that resulted in elevated levoglucosan, dacthal, endosulfan and gas phase PAH concentrations. Burned and unburned forest soil samples collected from the regional forest fire area showed that 34 to 100% of the pesticide mass was lost from soil due to burning. These data suggest that the transPacific and regional atmospheric transport of biomass burning emissions results in elevated PAH and pesticide concentrations in western North America. The elevated pesticide concentrations are likely due to re-emission of historically deposited pesticides from the soil and vegetation during the fire event.

Due to the 2011 labelling of styrene monomer as "reasonably anticipated to be a human carcinogen" by the National Institutes of Health's National Toxicology Program (NTP) and the controversy over whether styrene oligomers mimic the physiological effects of estrogen, an updated review of styrene monomer and oligomers in food and food contact materials (FCMs) was performed. The concentrations of styrene monomer and oligomers were determined in 24 polystyrene (PS) products and ranged from 9.3 to 3100 mg kg(-1) for the styrene monomer, 130-2900 mg kg(-1) for the sum of three styrene dimers, and 220-16,000 mg kg(-1) for the sum of six styrene trimers. Foods in contact with PS packaging had styrene monomer concentrations ranging from 2.6 to 163 ng g(-1); dimer concentrations from the limit of quantitation (LOQ) to 4.8 ng g(-1) and trimer concentrations were all below the LOQ (2 ng g(-1)). Diffusion coefficients (Dp) and partition coefficients (K) were also calculated for styrene dimers and trimers. The results presented here indicate that styrene monomer concentrations in foods have not significantly changed since the 1980s and monomer concentrations in food packaging quantified in this study were all below USFDA limits. Although styrene dimers and trimers are present in higher concentrations in PS FCMs than the monomer, their migration to food is limited because of their high K values (4 × 10(2) to 2 × 10(6)) and their low diffusion coefficients in PS products. Additionally, diffusion coefficients calculated using USFDA-recommended food simulants and Arrhenius plots describing the temperature dependence of styrene dimers and trimers can be used in future calculations of dietary intake of the styrene oligomers.

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