Aryl hydrocarbon receptor-mediated activity of particulate organic matter from the Paso del Norte airshed along the U.S.-Mexico border.

Abstract

In this study, we determined the biologic activity of dichloromethane-extracted particulate matter < 10 micro m in aerodynamic diameter (PM10) obtained from filters at three sites in the Paso del Norte airshed, which includes El Paso, Texas, USA; Juarez, Chihuahua, Mexico, and Sunland Park, New Mexico, USA. The extracts were rich in polycyclic aromatic hydrocarbons (PAHs) and had significant biologic activity, measured using two in vitro assay systems: ethoxyresorufin-(O-deethylase (EROD) induction and the aryl hydrocarbon-receptor luciferase reporter system. In most cases, both EROD (5.25 pmol/min/mg protein) and luciferase activities (994 relative light units/mg) were highest in extracts from the Advance site located in an industrial neighborhood in Juarez. These values represented 58% and 55%, respectively, of induction associated with 1 micro M ss-naphthoflavone exposures. In contrast, little activity was observed at the Northeast Clinic site in El Paso, the reference site. In most cases, luciferase and EROD activity from extracts collected from the Tillman Health Center site, situated in downtown El Paso, fell between those observed at the other two sites. Overall, a statistically significant correlation existed between PM10 and EROD and luciferase activities. Chemical analysis of extracts collected from the Advance site demonstrated that concentrations of most PAHs were higher than those reported in most other metropolitan areas in the United States. Calculations made with these data suggest a cancer risk of 5-12 cases per 100,000 people. This risk estimate, as well as comparisons with the work of other investigators, raises concern regarding the potential for adverse health effects to the residents of this airshed. Further work is needed to understand the sources, exposure, and effects of PM10 and particulate organic material in the Paso del Norte airshed.

Effect of chemical composition on the induction of DNA damage by urban airborne particulate matter

“…The seasonal differences in the total PAH levels were not as pronounced as that for the inorganic compounds found in PM: the ranges were 10-24 and 9-16 ng/m 3 in cold-dry and in the warm-dry seasons, respectively. The average PAH concentration (18.9 ng/m 3 ) was comparable to the 0.3-51.9 ng/m 3 range reported for other regions, such as Santiago, Chile, and Flanders, Belgium [Arrieta et al, 2003;Du Four et al, 2004], but it was higher than the PAH levels reported for rural areas and for some of the US cities (ranging from 0-0.4 ng/m 3 ) [WHO, 2000]. High proportions of carcinogenic PAHs (53.3%-73.3%) were found for the PAHs detected in the PM organic extracts, and these PAHs may be partially responsible for the observed genotoxicity.…”

Integrating Field Analyses with Laboratory Exposures to Assess Ecosystems Health

“…Humans are exposed to complex mixtures of PAHs via the diet, air and skin contact (Rothman et al, 1993;Schoket, 1999;Scherer et al, 2000;Arrieta et al, 2003;Oh et al, 2005). Low concentrations of high-molecular-weight PAHs, such as benzo [a]pyrene, are found in diesel exhaust and higher levels are found in woodsmoke (Burchiel et al, 2005).…”

Characterization and Comparison of Speciated Atmospheric Carbonaceous Particulates and Their Polycyclic Aromatic Hydrocarbon Contents in the Context of the Paso Del Norte Airshed Along the U.S.-MEXICO Border

“…Generally benzo[a]pyrene (BaP) is considered a human PAH carcinogenic activity marker (10,79,81). A number of these index rankings for the PAHs analyzed in this study are shown for comparison in Table 6 where it can be noted that the carcinogenicity tends toward the higher MW PAHs, although carcinogenicity peaks and then declines for MW >252.…”

“…While particulate matter (PM) exposures in El Paso are relatively low in contrast to most of the rest of the U.S., ubiquitous evening peaks in hourly PM 10 and PM 2.5 concentrations during still-air conditions (a four-fold increase over a few hour period) during winter months is particularly notable (7,8). Correspondingly, it has been shown that the risk of PM-induced mortality in El Paso is higher during still-air inversions than it is during sandstorms (9).…”

“…Correspondingly, it has been shown that the risk of PM-induced mortality in El Paso is higher during still-air inversions than it is during sandstorms (9). In addition, Arrieta et al have demonstrated that toxicologically active polycyclic aromatic hydrocarbons (PAHs) are present at different PM 10 collection sites in the Paso del Norte airshed although particulate-specific occurrences or concentrations were not identified (10). A recent study by Dallarosa et al found that particulate emissions from coal, wood, and combustion of fuels, especially diesel emissions, were responsible for the main PAH compounds, with phenanthrene showing the highest measured concentration (11).…”