Tom Harner

Background: Perfluorochemicals (PFCs) are detectable in the general population and in the human environment, including house dust. Sources are not well characterized, but isomer patterns should enable differentiation of historical and contemporary manufacturing sources. Isomer-specific maternal-fetal transfer of PFCs has not been examined despite known developmental toxicity of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in rodents. Objectives: We elucidated relative

This thesis considers the measurement and partitioning of several classes of persistent organic pollutants (POPs-namely, polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), and polycyclic aromatic hydrocarbons (PAHs). Octanol-air partition coeffcients (KoA) were measured for 18 PCBs, 24 PCNs, and 4 PAHs over a range of environmentally relevant temperatures. The results show that in all cases the value of KoA varied log-linearly with the inverse absolute temperature and that in general, the enthalpy associated with the transition from octanol to air, ΔHOA, was similar to the enthalpy of vaporization, ΔHvap. Greater partitioning was observed for coplanar and mono-ortho PCBs. The utility of KOA as a particle-gas partitioning descriptor was tested using results from Chicago air samples. The particle-gas partition coefficient, Kp, was calculated and plotted against KOA and against the subcooled liquid vapor pressure, p°L. Log-log plots of Kp versus P°L showed enrichment for the coplana PCBs and PAHs. This enrichment was resolved by KOA for the coplanar PCBs but only partially resolved for the PAHs. A KoA-based absorption model of particle-gas partitioning was compared with the Junge- Pankow adsorption model. The KOA model provided a better fit for PCBs but not PAHs, which were underestimated. An advantage of the KOA model is that it only requires knowledge KOA and the fraction of organic matter on the particle which are both easily measured. The Chicago field study led to the investigation of a new compound class, PCNs. A method was developed for quantifying PCNs based on the FID response of individual congeners in Halowax 1014, a technical mixture of 2 to 8- Cl congeners. PCNs were quantified in air samples from Chicago and three Arctic locations-a cruise track of the Eastern Arctic Ocean, Alert (Canada), and Dunai Island (Russia). The results show that PCNs contribute significantly to dioxin-type toxicity in air and merit further study. A review is made of the transport processes, concentrations, and implications of organochlorine contamination of the Canadian Arctic. Speculations are made regarding the relationships of global warming, physical chemistry of the compounds, and future trends of contaminants.

An interlaboratory study was initiated to investigate consistency in reported concentrations of polychlorinated naphthalenes (PCNs). Results are reported from the first phase of a study that examined the variability associated with different quantification methodologies, instrumentation and standards. Nine participating labs from seven countries quantified individual homolog groups, summation operator PCN (the sum of 2-8 chlorinated homologs), and selected congeners in two test solutions derived from Halowax 1014. The means of the reported summation operator PCN values were within less than 15% of the known concentrations of the two test solutions and the relative standard deviation among laboratories was 11%. However, the among laboratory variability was in the range 20-40% for individual PCN homologs and individual PCN congeners. These results suggest the need for additional interlaboratory studies and for the development of reference materials for PCN analysis. Future PCN interlaboratory comparison exercises are discussed that will utilize control materials and unknowns consisting of suitable environmental matrices.

Potentially-harmful chemicals could be released from many indoor materials, including consumer products and building materials, into indoor environments. Semi-volatile chemicals (SVOCs) due to their lower vapor pressure, are often present, either primarily in indoor dust or in both indoor air and indoor dust. Several types of SVOCs have been ,measured ,in indoor ,air and indoor dust of Ottawa residential

PFASs concentrations in dust samples collected from three microenvironments in Cairo ranged from 1.3 to 69 ng g(-1) with FTOHs being dominant. The 8:2 FTOH was detected in all samples. Among the FOSAs and FOSEs the MeFOSE was dominant while among ionic PFASs, PFOS and PFOA were most prominent. The concentrations of PFASs were among the lowest worldwide. Correlations between worldwide concentrations of PFOS + PFOA and country development indexes highlight higher usage and human exposure in more developed countries. Food packaging was analyzed for PFSAs, PFCAs and PAPs. The 6:2 and 8:2 monoPAPs were found to be above the MDL in 18% of the samples. PFOA was detected in 79% of the samples with median concentration of 2.40 ng g(-1). PFOS was detected in 58% of the samples with median concentration of 0.29 ng g(-1) while PFHxS and PFDS were below detection limit. Different human exposure scenarios were estimated.

The growing concern over these organohalogens, some of which have been found in human blood and appear to be widespread in the environment, led researchers to gather in Hamburg, Germany, in 2003 to evaluate the current state of methods to analyze for the organic contaminants. Jonathan Martin of the University of Toronto and 20 colleagues from industry, government, and academia

Persistent organic pollutants (POPs) and mercury are toxic chemicals that persist in the environment and can be transported by air and water over long distances from southern source regions to the remote Arctic. In cold environments, these chemicals can deposit onto the Arctic's surfaces and accumulate in Arctic wildlife, country foods and subsequently northern people to alarmingly high concentrations. Collaborating with other air monitoring programs for contaminants, INCATPA (International JC endorsed project #327) will measure these chemicals in air in the Canadian, Russian and American Arctic, as well as at potential source regions on the Asian Pacific Region and in North America. This will give us information on where these chemicals have come from, how much from which region and what climate conditions influence their movement to the Arctic. Data collected will be incorporated into environmental transport models to determine how future climate change will affect contaminant...

Cyclic and linear volatile methylsiloxanes (cVMSs and lVMSs, respectively) were measured in ambient air over a period of over one year in Toronto, Canada. Air samples were collected using passive air samplers (PAS) consisting of sorbent-impregnated polyurethane foam (SIP) disks in parallel with high volume active air samplers (HV-AAS). The average difference between the SIP-PAS derived concentrations in air for the individual VMSs and those measured using HV-AAS was within a factor of 2. The air concentrations (HV-AAS) ranged 22-351 ng m(-3) and 1.3-15 ng m(-3) for ΣcVMSs (D3, D4, D5, D6) and ΣlVMSs (L3, L4, L5), respectively, with decamethylcyclopentasiloxane (D5) as the dominant compound (∼75% of the ΣVMSs). Air masses arriving from north to northwest (i.e., less populated areas) were significantly less contaminated with VMSs compared to air arriving from the south that are impacted by major urban and industrial areas in Canada and the U.S. (p < 0.05). In addition, air concentr...

This thesis considers the measurement and partitioning of several classes of persistent organic pollutants (POPs-namely, polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), and polycyclic aromatic hydrocarbons (PAHs). Octanol-air partition coeffcients (KoA) were measured for 18 PCBs, 24 PCNs, and 4 PAHs over a range of environmentally relevant temperatures. The results show that in all cases the value of KoA varied log-linearly with the inverse absolute temperature and that in general, the enthalpy associated with the transition from octanol to air, DeltaHOA, was similar to the enthalpy of vaporization, DeltaHvap. Greater partitioning was observed for coplanar and mono-ortho PCBs. The utility of KOA as a particle-gas partitioning descriptor was tested using results from Chicago air samples. The particle-gas partition coefficient, Kp, was calculated and plotted against KOA and against the subcooled liquid vapor pressure, p°L. Log-log plots of Kp versus P°L showed e...

The accumulation of persistent organic pollutants by three passive sampling media--semipermeable membrane devices (SPMDs), polyurethane foam (PUF) disks, and an organic-rich soil--was investigated. The media were exposed to contaminated indoor air over a period of 450 days, and concentrations in the air and in the media were monitored for individual polychlorinated biphenyl (PCB) congeners and polychlorinated naphthalene homologue groups. Uptake was initially linear and governed by the surface area of the sampler and the boundary layer airside mass transfer coefficient (MTC). Mean values of the MTC were 0.13, 0.11, and 0.26 cm s-1 for SPMD, PUF, and soil, respectively. As the study progressed, equilibrium was established between ambient air and the passive sampling media for the lower molecular weight PCB congeners. This information was used to calculate passive sampler-air partition coefficients, KPSM-A. These were correlated to the octanol-air partition coefficient, and the resulting regressions were used to predict KPSM-A for the full suite of PCBs. Information on MTC, KPSM-A, surface area, and effective thickness of each sampler was used to estimate times to equilibrium for each medium. These ranged from tens of days for the lower molecular weight congeners to tens of years for the higher molecular weight PCBs. Expressions were also developed to relate the amount of chemical accumulated by the passive sampling media to average ambient air concentrations over the integration period of the sample.

... www.hanford.gov/dqo/ 6. Shoeib, M., Harner, T., Wilford, BH, Jones, KC and Zhu, J. (2005) Environ. Sci. Technol. (in press). ... Table 1. Concentrations of Fluorinated compounds in indoor and outdoor air samples and indoor house dusts 1 Ref 7 ...

Cover On a global scale, soils store more carbon than plants or the atmosphere. The cycling of this vast reservoir of reduced carbon is closely tied to variations in environmental conditions, but robust predictions of climate–carbon cycle feedbacks are hampered by a ...