Highest Total Polycyclic Aromatic Hydrocarbons Research Articles

Effectiveness of dermal cleaning interventions for reducing firefighters’ exposures to PAHs and genotoxins

Firefighters are exposed to carcinogenic and mutagenic combustion emissions, including polycyclic aromatic hydrocarbons (PAHs). Fire service and firefighter cancer advocacy groups recommend skin cleaning using wipes or washing with detergent and water after exposure to smoke, although these strategies have not been proven to reduce exposures to harmful combustion products such as PAHs. This study assessed dermal decontamination methods to reduce PAH exposures by firefighters participating in live fire training scenarios. Study participants (n = 88) were randomly assigned to an intervention group (i.e., two types of commercial skin wipes, detergent and water, or a control group who did not use any skin decontamination). PAHs were measured in personal air (during the fire) and dermal wipe samples (before and after fire suppression and after dermal decontamination). PAH metabolites and mutagenicity were measured in urine samples before and after fire suppression. Airborne PAH concentrations during the fire ranged between 200 and 3,970 μg/m3 (mean = 759 μg/m3, SD = 685 μg/m3). Firefighters had higher total PAHs and high-molecular-weight PAHs on their skin after the fire compared to before (1.3- and 2.2-fold, respectively, p < 0.01). Urinary PAH metabolites increased significantly following exposure to the training fires by 1.7 to 2.2-fold (depending on the metabolite, p < 0.001). Urinary mutagenicity did not differ significantly between pre- and post-fire for any of the decontamination methods. Detergent and water was the only intervention that removed a significant amount of total PAHs from the skin (0.72 ng/cm2 preintervention vs. 0.38 ng/cm2 postintervention, p < 0.01). However, fold changes in urinary PAH metabolites (i.e., pre- vs. post-exposure levels) did not differ among any of the dermal decontamination methods or the control group. These data suggest that despite on-site attempts to remove PAHs from firefighters’ skin, the examined interventions did not reduce the internal dose of PAHs. Future work should investigate preventing initial exposure using other interventions, such as improved personal protective equipment.

Particulate matter fingerprints in biofuel impacted tunnels in South America's largest metropolitan area

This study characterized the chemical composition of particulate matter (PM) from light- (LDV) and heavy-duty (HDV) vehicles based on two traffic tunnel samplings carried out in the megacity of São Paulo (Brazil), which has >7 million vehicles and intense biofuel use. The samples were collected with high-volume samplers and analyzed using chemical characterization techniques (ion and gas chromatography, thermal-optical analysis, and inductively coupled plasma mass spectroscopy). Chemical source profiles (%) were calculated based on the measurements performed inside and outside the tunnels. Identifying a high abundance of Fe and Cu for traffic-related PM in the LDV-impacted tunnel was possible, linked with the emission of vehicles powered by ethanol and gasohol (gasoline and ethanol blend). We calculated diagnostic ratios (e.g., EC/Cu, Fe/Cu, pyrene/benzo[a]pyrene, pyrene/benzo[b]fluoranthene, and fluoranthene/benzo[b]fluoranthene) characteristic of fuel exhausts (diesel/biodiesel and ethanol/gasohol), allowing their use in the assessment of the temporal variation of the fuel type used in urban sites. Element diagnostic ratios (Cu/Sb and Fe/Cu) pointed to the predominance of LDVs exhaust-related copper and can differentiate LDVs exhaust from brake wear emissions. The carbonaceous fraction EC3 was suggested as an HDV emission tracer. A higher total polycyclic aromatic hydrocarbons (PAHs) fraction of traffic-related PM2.5 was observed in the HDV-impacted tunnel, with a predominance of diesel-related pyrene and fluoranthene, as well as higher oxy-PAHs (e.g., 9,10-anthraquinone, associated with biodiesel blends) abundances. However, carcinogenic species presented higher abundances for the LDV-impacted tunnel (e.g., benzo[a]pyrene). These findings highlighted the impact of biofuels on the characteristic ratios of chemical species and pointed to possible markers for LDVs and HDVs exhausts.

Source-dependent compositional changes in coconut flavoured liquid smoke and its application in traditional Indian smoked fishery products

ABSTRACT Smoking is an age-old food preservation method. Intense smoking results in deposition of carcinogenic polycyclic aromatic hydrocarbons (PAH) in food. Replacing traditional smoking practices with application of liquid smoke or smoke flavouring is proven to reduce the PAH content without adversely affecting flavour of the products. This study explores source-dependant variations in composition of a coconut-flavoured liquid smoke. Liquid smoke produced from coconut husk (CH), coconut fibre (CF) and coconut fibre powder (CP) was analysed for total phenolic content, total carbonyls, titratable acidity, pH and PAH content. Resultant liquid smokes were also compared a commercial liquid smoke (CL) for composition. Total phenolic content in the liquid smokes ranged from 1518 ± 184 (CH), 1037 ± 110 (CF), 834 ± 48.23(CP) and 20047 ± 193 mg L−1 (CL). Commercial liquid smoke showed highest total PAH content 215 ± 15.45 ng ml−1 followed by 8.23 ± 1.47 (CP), 7.22 ± 1.44 (CF) and 0.64 ± 0.13 ng m−1 (CH). Further, process parameters for producing ‘masmin’ – a popular traditional smoked and dried ready-to-eat product – by replacing traditional smoking practices with liquid smoking were standardised using Response Surface Methodology. Spraying cooked skipjack tuna (Katsuwonus pelamis) loins with coconut husk liquid smoke containing 4% salt for 155 min at flow rate of 3 L hr−1 and chamber temperature of 60°C was found to give the product a matching flavour with traditional masmin.

Abstract D093: Who carries the excess cancer risk burden: Implications of disparities in polycyclic aromatic hydrocarbon exposure

Abstract Polycyclic aromatic hydrocarbons (PAHs) are a toxic and ubiquitous class of environmental chemicals sourced from industrial practices, tobacco smoke, grilled and smoked meats, car exhaust, and other human and natural sources. Many PAHs are also considered carcinogenic. In this study, we sought to identify the most vulnerable populations for high PAH exposure in the U.S. and resultant excess cancer risk. Urinary biomarker data were collected from 2005-2014 by the U.S. CDC National Health and Nutrition Examination Survey for metabolites of four PAHs: naphthalene, fluorene, phenanthrene, and pyrene. We conducted reverse dosimetry modeling to estimate exposure to the four PAHs, singly and in sum, for each adult individual in the dataset, expressed as a daily intake rate. These were calculated using known excretion fractions and molecular weights specific to each PAH parent or metabolite compound, standardized adult urine output, and individual body weights. We then stratified these exposures by demographic factors (age, gender, race/ethnicity, education level, and family income), in addition to lifestyle factors (smoking status, exposure to secondhand smoke, and BMI). We analyzed these stratified demographic and lifestyle groups according to effect size, and analyzed subpopulations within each group by principal component analysis, so as to determine the most influential factors and the most vulnerable subpopulations for high PAH exposure. We then calculated lifetime excess cancer risk for subpopulations based on their PAH exposure using benzo(a)pyrene (BaP) toxic equivalency factors, BaP cancer slope factor, and a 70-year lifespan estimation. There were 8570 individuals in the final dataset, although smoking status information available for 3818 of these individuals. Unsurprisingly, smokers and those exposed to secondhand smoke had the highest total PAH intake rates. 36.9% of PAH exposure variance was explained by the demographic and lifestyle factors included in this analysis, with an additional 4.8% explained by smoking status and secondhand smoke exposure interactions with other demographic variables such as race/ethnicity. However, only 7.5% of the PAH exposure variance was explained when all smokers and those exposed to secondhand smoke were removed from the dataset, indicating the strength of association between tobacco smoke exposure and PAH intake. Demographic subpopulations such as those who did not complete high school, middle-income bracket ($45-75,000), and other Hispanic racial/ethnic identity had higher PAH exposure and resultant excess cancer risk, while higher income bracket (75,000+), those with a college degree, Asian identity, and females in general had lower PAH exposure levels and lower excess cancer risk. These results suggest that, in addition to smokers and those exposed to secondhand smoke, there are demographic subpopulations with disproportionately high PAH exposure and resultant excess cancer risk burden, which is a public health concern. Citation Format: Larisa M Gearhart-Serna, Moises Tacam, Jr., Theodore A Slotkin, Gayathri R Devi. Who carries the excess cancer risk burden: Implications of disparities in polycyclic aromatic hydrocarbon exposure [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D093.

Anthropogenic PAHs in Sediment-Dwelling Biota from Mangrove Areas of the Calabar River, SE Niger Delta, Nigeria

Polycyclic aromatic hydrocarbons (PAHs) in mangrove sediment-dwelling biota (crabs and molluscs) from the Calabar River, SE Niger Delta of Nigeria were analyzed using GC-MS in order to assess the degree of contamination of the river by anthropogenic activity. The associated sediment samples (where these biota were collected) showed much higher total PAH (TPAH) concentration (16,028.3 ng/g dry weight (dw)) at the upper mangrove area (UMA) than that found toward the river mouth (MR; 1,667.5 ng/g dw). However, the mean TPAH levels were higher in molluscs (16,749.8 ng/g ww) and crabs (29,325.1 ng/g ww) at theMR, and in molluscs (28,580.8 ng/g ww) and crabs (71,782.6 ng/g ww) at the UMA than in the associated sediments, indicating occurrence of bio-accumulation/bio-concentration of PAHs in tissues of these organisms. The results revealed that molluscs are safer to consume than crabs. One way analysis of variance (ANOVA) indicated no significant relationship between lipid content or body size of organisms and contaminant load probably because of non-equilibrium situation: smaller animals accumulated more PAHs than their larger counterparts, suggesting different uptake and elimination rates for these compounds. Biota-sediment accumulation factors (BSAFs) varied among the organisms (4.84-14.98) and were generally lower for highly polluted site (UMA; fresh water area) and higher for area of low anthropogenic pressure (MR- brackish water area). Risk assessment against USEPA standard show the biota to be highly contaminated with carcinogenic PAHs and may pose life-time cancer risk, especially to residents of the riverine/coastal communities who often consume more of these organisms than those living hinterland.

PAH emission from various industrial stacks

The emission of polycyclic aromatic hydrocarbons (PAHs) from various industrial stacks (blast furnace, basic oxygen furnace, coke oven, electric arc furnace, heavy oil plant, power plant and cement plant) in southern Taiwan were investigated. PAH concentrations ( μg/N m 3) and PAH emission factors ( μg/kg feedstock) were determined. In addition to these eight stationary industrial stacks, an industrial waste incinerator, a diesel engine and a gasoline-powered engine were selected and combined for the identification of source indicatory-PAHs in this study. The qualitative contribution of PAHs to the ambient air by various sources was estimated by factor analysis. Combustion of heavy oil produced considerably higher 4, 5 and 6+7-ring PAH concentration than other stacks. In addition, the HMW (higher molecular weight) PAH concentrations were significantly higher for the coke oven, the electric arc furnace and heavy oil combustion. Measured total-PAHs emission factors of eight stationary sources were between 77.0 and 3970 μg/kg feedstock, while BaP (the most carcinogenic PAH) emission factors were between 1.87 and 15.5 μg/kg feedstock. Among these eight emission sources, the heavy oil plant had both the highest total-PAH and the highest BaP emission factor. Indicatory PAHs of the cement plant were AcPy, Acp and Ant, which are all 3-ringed PAHs. However, the indicatory PAHs of the industrial waste incinerator were IND and CHR. For mobile sources (diesel- and gasoline-powered vehicles), the indicatory PAHs were mainly lower molecular weight PAHs (AcPy, FL and Flu). By using factor analysis, the cursorily qualitative analysis of PAH emission was found to be practicable.

Polycyclic Aromatic Hydrocarbons in the Sediments of the Milwaukee Harbor Estuary, Wisconsin, U.S.A.

From 1990 to 1994, a total of 21 sediment cores and 37 grab sediment samples were collected from the Milwaukee Harbor Estuary. Each sediment core was sectioned and dated using 210Pb and137 Cs radioisotope techniques. A total of 305 samples were analyzed for sixteen polycyclic aromatic compounds (PAHs). Grain size distribution, porosity, and total organic carbon content as measured by loss on ignition were also determined. The results provide a historical overview of the impact of industrialization in the Milwaukee area. Although highly variable, the concentration profile of PAHs show, in general, peaks in the 1950's through 1980's. The PAH concentrations have declined since then for most sediment cores. The current levels of total PAHs in most surface sediment samples range from 25 to 200 ppm. A few cores, some of which were collected in 1994, have an elevated PAH concentration at the surface. Toxicity of the surface sediments was evaluated by comparing with the benchmark values developed by the United States National Oceanic and Atmospheric Administration (NOAA). The most heavily contaminated area was found in the Kinnickinnic River between the Becher Street Bridge and the Wisconsin Wrecking Company Wharf. The highest total PAH concentration determined from seven vibra cores collected in this area ranges from 380 to 1000 ppm. The former Wisconsin Solvay Coke Company may have been a major point source of PAHs until the 1970's. Highway traffic and various industrial discharges also contribute to the sediment PAHs in this area.