Mark Loewen

Persistent organic pollutants and mercury in the Himalaya

Persistent organic pollutants and mercury are important contaminants due to their persistence in the environment and potential toxic effects on ecosystems and humans. Concerns related to these contaminants are particularly pertinent in Asia where the use of pesticides and mercury emissions have been increasing dramatically due to changing agricultural practices and rapidly expanding industrialization. Based on studies in European and North American mountain regions, evidence is increasing that alpine regions function as regional convergence zones for selected organic pollutants due to an effect called orographic cold trapping. It is hypothesized that such an effect may be particularly pronounced in the Himalaya because of dramatic elevational temperature and precipitation gradients relative to contaminant source regions in its immediate vicinity, and because of the regional monsoon system that has been shown to deliver particles and inorganic air pollutants to higher altitudes. A review of studies of persistent organic pollutants and mercury in the Himalayan ecosystem reveals that measurements of these contaminants are sparse and rarely adhere to strict quality control procedures, making it difficult to judge whether relatively high concentrations reported for these materials are indeed an indication of efficient transfer of toxic contaminants to Himalayan ecosystems. Knowledge gaps are identified and suggestions are made for research that would allow for the testing of the hypothesis that the Himalaya is an important cold trap for semi-volatile organic contaminants and mercury.

Chronic exposure to perfluorinated compounds: impact on airway hyperresponsiveness and inflammation

Emerging epidemiological evidence reveals a link between lung disease and exposure to indoor pollutants such as perfluorinated compounds (PFCs). PFC exposure during critical developmental stages may increase asthma susceptibility. Thus, in a murine model, we tested the hypothesis that early life and continued exposure to two ubiquitous household PFCs, perfluorooctanoic acid (PFOA) and perflurooctanesulfonic acid (PFOS), can induce lung dysfunction that exacerbates allergen-induced airway hyperresponsiveness (AHR) and inflammation. Balb/c mice were exposed to PFOA or PFOS (4 mg/kg chow) from gestation day 2 to 12 wk of age by feeding pregnant and nursing dams, and weaned pups. Some pups were also sensitized and challenged with ovalbumin (OVA). We assessed lung function and inflammatory cell and cytokine expression in the lung and examined bronchial goblet cell number. PFOA, but not PFOS, without the OVA sensitization/challenge induced AHR concomitant with a 25-fold increase of lung macrophages. PFOA exposure did not affect OVA-induced lung inflammatory cell number. In contrast, PFOS exposure inhibited OVA-induced lung inflammation, decreasing total cell number in lung lavage by 68.7%. Interferon-γ mRNA in the lung was elevated in all PFC-exposed groups. Despite these effects, neither PFOA nor PFOS affected OVA-induced AHR. Our data do not reveal PFOA or PFOS exposure as a risk factor for more severe allergic asthma-like symptoms, but PFOA alone can induce airway inflammation and alter airway function.

Vanishing High Mountain Glacial Archives: Challenges and Perspectives

Perspectives Qianggong Zhang,*,†,‡,∇ Shichang Kang,*,‡,§ Paolo Gabrielli, Mark Loewen, and Margit Schwikowski †Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, P.R. China ‡CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, P.R. China State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, P.R. China School of Earth Sciences, 275 Mendenhall Laboratory, The Ohio State University, 125 South Oval Mall, Columbus, Ohio 43210, United States Byrd Polar and Climate Research Center, The Ohio State University, 108 Scott Hall, 1090 Carmack Road, Columbus, Ohio 43210-1002, United States Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada PSI, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland

The role of perfluooctanoic acid (PFOA) in airway hyperrepsoniveness

Objective/purpose Evidence is emerging that human exposure to environmentally ubiquitous perfluorooctanoic acid (PFOA), used commonly for its household stain repellency characteristics, is associated with immunologic changes. Data from adults near an industrial PFOA disposal site demonstrated a strong negative correlation between blood PFOA concentrations and some immune responses. We propose to test if early life exposures to PFOA are playing a role in modifying airway responses. Methods Although several animal exposure models have been used to test ingestible PFOA toxicity using gavage methods at high concentrations, we chose to expose timedpregnant Balb/C dams from GD-2 at more environmentally relevant concentrations (4 mg/kg diet PFOA Sigma Aldrich) mixed into the diet (Purina 5001). Dams were allowed to eat either a control or contaminated diet adlibitum (~4-6 g/day) through pregnancy and lactation. Upon weaning, lung mechanics of the exposed and control dams were measured using a flexiVent and liver weights measured. Dams were not sensitized to allergen. Findings Baseline lung mechanics and airway responsiveness of PFOA-exposed, non-sensitized mice were not significantly different from controls, however, liver weight as a function of body weight was significantly higher in exposed dams compared to controls (9.4% vs 5.5% p = 0.0003).