Exposures to environmental phenols in Southern California firefighters and findings of elevated urinary benzophenone-3 levels.

Firefighters are at increased risk for exposure to toxic chemicals compared to the general population, but few studies of this occupational group have included biomonitoring. We measured selected phenolic chemicals in urine collected from 101 Southern California firefighters. The analytes included bisphenol A (BPA), triclosan, benzophenone-3 (BP-3), and parabens, which are common ingredients in a range of consumer products. BP-3, BPA, triclosan, and methyl paraben were detected in almost all study subjects (94-100%). The BP-3 geometric mean for firefighters was approximately five times higher than for a comparable National Health and Nutrition Examination Survey (NHANES) subgroup. Demographic and exposure data were collected from medical records and via a questionnaire, and covariates were examined to assess associations with BP-3 levels. BP-3 levels were elevated across all firefighter age groups, with the highest levels observed in the 35 to 39year old group. Body fat percentage had a significant inverse association with BP-3 concentrations. Our results indicate pervasive exposure to BP-3, BPA, triclosan, and methyl paraben in this population of firefighters, consistent with studies of other populations. Further research is needed to investigate possible explanations for the higher observed BP-3 levels, such as occupational or California-specific exposures.

Pulmonary inflammatory effects of source-oriented particulate matter from California's San Joaquin Valley.

The EPA regulates ambient particulate matter (PM) because substantial associations have been established between PM and health impacts. Presently, regulatory compliance involves broad control of PM emission sources based on mass concentration rather than chemical composition, although PM toxicity is likely to vary depending upon PM physicochemical properties. The overall objective of this study was to help inform source-specific PM emission control regulations. For the first time, source-oriented PM was collected from the atmosphere in Fresno, CA, onto 38 source/size substrates. Mice were exposed via oropharyngeal aspiration to equivalent mass doses [50 µg] of two size fractions: ultrafine (Dp < 0.17µm) and submicron fine (0.17 < Dp < 1 µm) during summer and winter seasons. At 24 hours post-exposure, cellular and biochemical indicators of pulmonary inflammation were evaluated in the bronchoalveolar lavage fluid. Significant inflammatory responses were elicited by vehicle, regional background, and cooking PM sources that were dependent on season and particle size. This is the first study of source-oriented toxicity of atmospheric PM and supports source-specific emissions control strategies.

Allergic airway inflammation is differentially exacerbated by daytime and nighttime ultrafine and submicron fine ambient particles: heme oxygenase-1 as an indicator of PM-mediated allergic inflammation.

Ambient particulate matter (PM) originates from a range of sources and differs in composition with respect to season, time of day, and particle size. In this study, ambient PM samples in the ultrafine and submicrometer fine range were tested for the potential to exacerbate a murine model of allergic airway inflammation when exposure occurs solely during allergic sensitization, but not during subsequent allergen challenge. Temporally resolved and size-segregated PM samples were used to understand how summer or winter, day or night, and ambient ultrafine and submicrometer fine particle size influence PM's ability to exacerbate allergic inflammation. PM was collected in urban Fresno, CA. BALB/c mice were exposed to PM and house dust mite allergen (HDM) via intranasal aspiration on d 1, 3, and 5. HDM challenge occurred on d 12-14, with inflammation assessed 24 h following final challenge. While season or particle size did not predict allergic inflammation, daytime ultrafine and submicrometer fine particles significantly increased total cellular inflammation, specifically lymphocyte and eosinophil infiltration, compared to allergic controls. Further studies examined PM-mediated changes within the lung during the period where allergen sensitization occurred by measuring direct effects of PM on pulmonary oxidative stress and inflammation. Pulmonary levels of heme oxygenase-1 (HO-1), a biomarker of oxidative stress, but not cellular inflammation, demonstrated a remarkable correlation with the degree of allergic inflammation in animals sensitized to allergen and PM concomitantly, suggesting acute PM-mediated HO-1 levels may serve as a predictive indicator of a particle's ability to exacerbate allergic airway inflammation.

Nanoparticles, lung injury, and the role of oxidant stress.

The emergence of engineered nanoscale materials has provided significant advancements in electronic, biomedical, and material science applications. Both engineered nanoparticles and nanoparticles derived from combustion or incidental processes exhibit a range of physical and chemical properties that induce inflammation and oxidative stress in biological systems. Oxidative stress reflects the imbalance between the generation of reactive oxygen species and the biochemical mechanisms to detoxify and repair the damage resulting from reactive intermediates. This review examines current research on incidental and engineered nanoparticles in terms of their health effects on lungs and the mechanisms by which oxidative stress via physicochemical characteristics influences toxicity or biocompatibility. Although oxidative stress has generally been thought of as an adverse biological outcome, this review also briefly discusses some of the potential emerging technologies to use nanoparticle-induced oxidative stress to treat disease in a site-specific fashion.

Influence of season and location on pulmonary response to California's San Joaquin Valley airborne particulate matter.

Season and location have documented impacts on particulate matter (PM)-induced morbidity and mortality. Seasonal and regional influences on the physical and chemical properties of PM2.5 (also known as fine/ultrafine PM) contribute to differences in exposure burden and adverse respiratory health outcomes experienced in California's San Joaquin Valley (SJV), which ranks among the worst in the nation for PM pollution. Current regulations are driven by the association between mass concentrations and adverse health outcomes. However, this association is difficult to reproduce in toxicological studies and suggests a role for other parameters, such as chemical composition, involved in PM-induced adverse pulmonary health effects. Pulmonary toxicity of summer/winter and rural/urban SJV PM was evaluated given the unique geography, metereology and sources of the region. Healthy juvenile male mice inhaled summer/winter and urban/rural concentrated ambient PM (CAP) or ambient PM for 6 h/d for 10 d, and pulmonary inflammatory responses were measured 48 h postexposure. Exposure concentrations ranged from 10 to 20 µg/m³ for ambient air control mice and from 86 to 284 µg/m³. Mice exposed to rural but not urban CAP, displayed significant neutrophil influx that was more than 50-fold greater than control levels, which ranged from 21 to 60 neutrophils/ml for all experiments. Pulmonary neutrophilic inflammation was measured despite lower CAP concentrations in the rural compared to the urban location and in the absence of cytotoxicity, oxidative stress, or elevations in cytokine and chemokines expression. Further, the inflammatory responses induced by rural winter CAP were associated with the highest levels of organic carbon (OC) and nitrates (NO3⁻). Evidence indicates that regional/seasonal influences on PM chemical composition rather than PM mass may be associated with increased PM-induced adverse health effects.

Aerosols in the agricultural setting.

This report summarizes discussions chaired by Kent Pinkerton held during the New Paths: Health and Safety in Western Agriculture conference, November 11-13, 2008. Research on air quality and aerosols in the agricultural setting was presented and discussed, providing insight into critical issues by many of the prominent scientists in this field. The panel discussion provided an overview of recent advances and future directions for research regarding sampling and exposure assessment of biologically active aerosols. This analysis considers chemical composition, individual exposures, and subsequent health effects experienced in large- and small-scale farming operations. The breakout discussion focused on other sources of particulate matter associated with agricultural activities prominent in various regions of the western United States. The complementary directions for these discussions fully demonstrate the wide range of concerns and issues that exist regarding bioaerosols and ambient dust associated with agricultural activities.