Martinotti I

Urinary hydroxylated metabolites of polycyclic aromatic hydrocarbons as biomarkers of exposure in asphalt workers

Abstract Background. Fumes and vapours released during laying of hot asphalt mix have been recognised as a major source of exposure for asphalt workers. Objectives. We investigated the relationships between inhalation exposure to asphalt emissions and urinary biomarkers of polycyclic aromatic hydrocarbons (PAHs) in asphalt workers (AW, n=75) and in ground construction workers (CW, n=37). Methods. Total polyaromatic compounds (PAC) and 15 priority PAHs in inhaled air were measured by personal sampling. Hydroxylated PAH metabolites (OH-PAHs) (2-naphthol, 2-hydroxyfluorene, 3-hydroxyphenanthrene, 1-hydroxypyrene, 6-hydroxychrysene and 3-hydroxybenzo[a]pyrene) were determined in urine spot samples collected in three different times during the work week. Results. Median vapour-phase PAC (5.5 µg m–3), PAHs (≤50 ng m–3) and OH-PAHs (0.08–1.11 µg l–1) were significantly higher in AW than in CW, except in the cases of air naphthalene and 2-naphthol. Airborne levels of particle-phase contaminants were similar in the two groups and much lower than vapour-phase levels; metabolites of particulate PAHs were never found in quantifiable amounts. An appreciable increase in OH-PAH levels during the work day and work week was found in AW; median levels for 2-hydroxyfluorene, 3-hydroxyphenanthrene and 1-hydroxypyrene were, respectively, 0.29, 0.08 and 0.18 at baseline; 0.50, 0.18 and 0.29, pre-shift; 1.11, 0.44 and 0.44 µg l–1, post-shift. Each OH-PAH exhibited a characteristic profile of increase, reflecting differences in half-lives of the parent compounds. In non-smoking subjects, positive correlations were found between vapour-phase PAC or PAHs and OH-PAHs both in pre- and post-shift samples (0.34 ≤ r≤69). Smokers exhibited 2–5-fold higher OH-PAHs than non-smokers, at any time and at both workplaces. Conclusions. Our results suggest that OH-PAHs are useful biomarkers for monitoring exposure to asphalt emissions. The work-related exposure to PAC and PAHs was low in all AW, but urinary metabolites reflected exposure satisfactorily.

Evaluation of Exposure to PAHs in Asphalt Workers by Environmental and Biological Monitoring

Abstract:  In the present article we assessed exposure to polycyclic aromatic hydrocarbons (PAHs) in Italian asphalt workers (AW, n= 100), exposed to bitumen fumes and diesel exhausts, and in roadside construction workers (CW, n= 47), exposed to diesel exhausts, by means of environmental and biological monitoring. 1‐Hydroxypyrene (OH‐Py) was determined in urine spot samples collected, respectively, after 2 days of vacation (baseline), before, and at the end of the monitored work shift, in the second part of the workweek. Median airborne levels during the work shift of 15 PAHs (both vapor and particulate phases), from naphthalene (NAP) to indeno(1,2,3‐cd)pyrene, ranged from below 0.03 to 426 ng/m3. Median excretion values of OH‐Py in baseline, before‐ and end‐shift samples were 228, 402, and 690 ng/L for AW and 260, 304, and 378 ng/L for CW. Lower values were found in nonsmokers compared to smokers (e.g., in AW 565 and 781 versus 252 and 506 ng/L in before‐shift and end‐shift samples, respectively). In all subjects a weak correlation between personal exposure to the sum of airborne 15 PAHs and OH‐Py was observed (r= 0.30). The results of this article show that AW experienced a moderate occupational exposure to airborne PAHs, resulting in a significant increase of urinary OH‐Py during the workday and the workweek. The contribution of working activities to internal dose was in the same order of magnitude of the contribution of cigarette smoking.

Dermal exposure to polycyclic aromatic hydrocarbons in asphalt workers

Objectives To assess dermal exposure to 16 polycyclic aromatic hydrocarbons (PAHs) in asphalt workers by applying polypropylene pads to six body sites (neck, shoulder, upper arm, wrist, groin, ankle), to identify the compounds and exposure sites most representative, and to integrate dermal exposure results with environmental and biological data. Methods Twenty-four asphalt workers were recruited. Dermal exposure was assessed during a single work shift. Sixteen PAHs (from naphthalene to indeno[1,2,3-cd]pyrene) were quantified via gas chromatography-mass spectrometry. Airborne exposure, urinary PAHs and monohydroxy metabolites were also investigated. Results Phenanthrene (PHE), present in all samples, was the most abundant compound (median 0.805–1.825 ng/cm2). Benzo[a]pyrene (BaP) was present in 75% of the samples (0.046–0.101 ng/cm2). Wrist had the highest contamination, with median PHE, pyrene (PYR), and BaP concentrations of 1.825, 0.527, and 0.063 ng/cm2. PHE and PYR on wrist correlated with almost all 3- to 4-ring PAHs (0.405≤r≤0.856), but not with BaP; BaP correlated with almost all 4- to 6- ring PAHs (0.584≤r≤0.633). Significant correlations were observed between PHE level, airborne exposure, and the corresponding urinary PHE and monohydroxy metabolites. For PYR, significant correlations existed only between urinary PYR and monohydroxy metabolites. Multiple linear regression analysis revealed that 42% of the end-of-shift monohydroxy metabolites were the result of airborne exposure, dermal exposure, and baseline levels of biomarkers. Conclusions Dermal exposure to PAHs was in the low ng/cm2 range. PHE or PYR and BaP were the most representative compounds and the wrist was the best location to perform dermal exposure assessments. Both dermal and airborne exposure contributed to the total body burden of PAHs, though the relative contribution was analyte-dependent.

Unmetabolized Polycyclic Aromatic Hydrocarbons in Urine as Biomarkers of Low Exposure in Asphalt Workers

The aim of the study was the assessment of low-level exposure to polycyclic aromatic hydrocarbons (PAHs) by biological monitoring focusing on measurement of unmetabolized PAHs in urine. Italian asphalt workers (AW, n = 100) and roadside construction workers (CW, n = 47) were investigated by measurement of unmetabolized PAHs and 1-hydroxypyrene (OH-Py) in urine spot samples collected respectively after two days of vacation (baseline), before and at the end of the monitored workshift, in the second part of the workweek. Personal exposure was also assessed by use of active samplers collecting both vapor- and particulate-phase PAHs. Median airborne levels during the workshift of 15 PAHs (both vapor and particulate phases), from naphthalene to indeno(1,2,3-cd)pyrene, ranged from below 0.03 to 426 ng/m 3 . Median excretion values of OH-Py in end-shift samples was 690 ng/L for AW and 378 ng/L for CW (p < 0.01). Urinary low-boiling PAHs were detected in the majority of the samples. Median levels for urinary naphthalene, phenanthrene, fluoranthene, and pyrene in end-shift samples were 117, 50, 8, and 6 ng/L in AW and 104, 19, 5, and 4 ng/L in CW, respectively. Significantly higher levels of most of the unmetabolized compounds were found in AW than in CW. Moreover, in AW samples the urinary excretion of most analytes increased during the work shift (before-shift vs. end-shift) and the workweek (baseline vs. before-shift). Urinary high-boiling PAHs were found in less than 10% of the samples. Significant correlations between airborne and urinary PAHs were observed. The results of this study show that low-boiling unmetabolized PAHs in urine may be suggested as biomarkers of low-level exposure to PAHs.

Assessment of Exposure to Polycyclic Aromatic Hydrocarbons (PAH) in Italian Asphalt Workers

The purpose of the work was the assessment of exposure to Polycyclic Aromatic Hydrocarbons (PAH), a family of ubiquitous pollutants of which some are carcinogens, in 100 Italian asphalt workers (exposed to bitumen fumes and diesel exhausts) and in a reference group of 47 ground construction operators (exposed only to diesel exhausts, reference group). The protocol included interview via questionnaires, environmental air-monitoring (active personal sampling during the work shift), dermal contamination measures (six pads placed on workers wrist, neck, arm, chest, thigh, and ankle), and biological monitoring (determination of 1-hydroxypyrene in urine spot samples collected three at different moments: baseline after two days of vacation, before shift, and at end shift on a day in the second half of the week). Analysis of the most relevant PAH, according to the American Environmental Protection Agency, EPA, was performed by High Performance Liquid Chromatography (HPLC) by fluorimetric detector. Median airborne levels of PAH ranged from 426 to below 0.03 ng/m3. Vapor-phase PAH, apart from naphthalene, were significantly higher in asphalt workers than in the reference group. Particle-phase PAH were similar and very low (< 1 ng/m3) in both exposure groups. Exposure levels did not vary in different work-tasks. Excretion of urinary 1-hydroxypyrene (expressed by ng/g creatinine) showed a significant increase at different sampling moments in asphalt workers, smokers, and non-smokers: baseline was lower than at the beginning of the workshift, and values were even higher in the end workshift sample. Comparing the two groups, a significant difference in the levels of metabolite does not appear, whereas this trend can be viewed observing the non-smokers. All body regions monitored by pads showed equivalent values levels of Dermal Deposition Density in both exposure groups. The measured amount of dermal contamination was significantly higher in asphalt workers than in ground construction operators. In asphalt workers, skin contamination was significantly higher during asphalt paving than during asphalt mixing. Dermal Exposure Rate was calculated about threefold higher than Airborne Exposure Rate; whereas considering toxicokinetical information (Kp, lag time, experimental dermal absorption data) and hygienistic data (particle size of bitumen fume), the relevance of dermal absorption is lower than respiratory. The results of this study demonstrate that asphalt workers experience slight occupational exposure to PAH, both by inhalatory and dermal routes, resulting in a significant increase of urinary 1-hydroxypyrene during the workweek.

Application of Ultraviolet Spectrophotometry to Estimate Occupational Exposure to Airborne Polyaromatic Compounds in Asphalt Pavers

An ultraviolet (UV) spectrophotometric procedure was devised for the determination of polycyclic aromatic compound-oriented organic soluble matter in vapors and particulate collected from emissions of hot asphalt mix. Ultrasonic extraction was carried out with acetonitrile, followed by UV measurements at 254 nm. Polycyclic aromatic compounds (PACs) in volatile and particulate fraction were quantified as phenanthrene or benzo[k]fluoranthene equivalents. A comparison between UV and high-pressure liquid chromatography with fluorescence detection showed that PACs were one to three orders of magnitude higher than the sum of 15 priority polycyclic aromatic hydrocarbons (PAHs); still, significant correlations were found between volatile or particulate PACs and, respectively, total volatile or particulate PAHs. Moreover, in the particulate phase, PACs correlated with total particulate matter quantified by gravimetry. The proposed procedure was employed in a field study for monitoring personal exposure to asphalt emissions of workers engaged in road construction. Observed levels of acetonitrile-soluble PACs in air samples were very low (2–20 μg/m 3 ); however, asphalt pavers were exposed to significantly higher concentrations of volatile PACs than construction workers (geometric mean, 5.9 μg/m 3 vs. 4.1 μg/m 3 ). This method for estimating the global content of volatile or particulate PACs in air samples satisfies our requirements of simplicity and is suitable for conducting an initial screening to assess exposure to airborne polyaromatic organics in asphalt pavers.