Environmental and biological monitoring of occupational exposure to polynuclear aromatic hydrocarbons during highway pavement construction in Italy

Bitumen fumes and PAHs in asphalt road paving: Emission characteristics, determinants of exposure and environmental impact

BACKGROUND

Asphalt road paving and its subsequent complex airborne emissions have raised concerns about occupational exposures and environmental impacts. Although several studies described bitumen fumes or Polycyclic Aromatic Hydrocarbons (PAH) emissions at specific worksites, no comprehensive studies have characterised road paving emissions and identified the main determinants of exposure.

METHODS

A 10-year study from 2012 to 2022 was performed to examine the pollutants resulting from bitumen fume emissions and covering the main processes used in road paving (asphalt production, mechanical rolled asphalt paving, manual paving, mastic asphalt paving, emulsion paving, and coal-tar asphalt milling). A total of 623 air samples were collected at 63 worksites (on 290 workers, in the environment and near emission sources), and bitumen fumes, PAHs, aldehydes and volatile organic compounds were analysed. Biomonitoring campaigns were performed on 130 workers to assess internal exposure to PAHs.

RESULTS

Fume emissions revealed complex mixtures of C₁₀-C₃₀ compounds, including linear saturated hydrocarbons (C₆-C₁₂), alicyclic hydrocarbons and aliphatic ketones. PAHs were dominated by 2-3 aromatic ring compounds (naphthalene, fluorene, and phenanthrene), and C₁-C₁₃ aldehydes were identified. Binder proportion, paving temperature, outdoor temperature, workload and job category influenced airborne concentrations. A significant temporal trend was observed over the time period of the study, with decreasing BF and PAH exposures. PAH biomonitoring was consistent with air samples, and urinary metabolites of 2-3 ring PAHs dominated over 4-5 ring PAHs. Occupational exposures were generally far lower than exposure limits, except coal-tar asphalt milling activities. Very low environmental concentrations were measured, which highlights a negligible contribution of paving emissions to global environmental pollution.

CONCLUSION

The present study confirmed the complex nature of bitumen fumes and characterised the main determinants of exposure. The results highlight the need to reduce the paving temperature and binder proportion. Recycled asphalt pavement use was not associated with higher emissions. The impact of paving activities on environmental airborne pollution was deemed negligible.

Internal exposure risk based on urinary metabolites of PAHs of occupation and non-occupation populations around a non-ferrous metal smelting plant

The emission of various metals from non-ferrous metal smelting activities is well known. However, relative investigations on potential occupational exposure of organic pollutants are still limited. Herein, total of 619 human urine samples were collected from workers engaged in smelting activities and residents living near and/or far from the smelting sites, and ten mono-hydroxylated metabolites of polycyclic aromatic hydrocarbons (OH-PAHs) in human urine were determined. The median levels of Σ₁₀OH-PAHs in smelting workers (25.6 ng/mL) were significantly higher (p < 0.01) than that of surrounding residents (9.00 ng/mL) and rural residents as the control (8.17 ng/mL), indicating an increase in occupational PAH exposure in non-ferrous metal smelting activities. The composition profiles of OH-PAH congeners were similar in three groups, in which naphthalene metabolites accounted for 76-82% of the total. The effects of smoking, drinking, gender, BMI, and occupational categories on urinary OH-PAHs were considered. The partial correlation analysis showed an insignificant effect of non-ferrous metal smelting activities on PAH exposure for surrounding residents. In the health risk assessments, almost all smelting workers had cancer risks exceeded the acceptable level of 10^-6. This study provides a reference to occupational PAH exposure and reinforce the necessary of health monitoring among smelting workers.

Emission of Volatile Organic Compounds in Crumb Rubber Modified Bitumen and Its Inhibition by Using Montmorillonite Nanoclay

Bitumen emits a large amount of volatile organic compounds (VOCs) during the production and construction of asphalt mixture, which can cause both environmental hazards and health risks. In this study, a setup was designed to collect the VOCs released by base and crumb rubber-modified bitumen (CRMB) binders and their composition was characterized by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Next, organic montmorillonite (Mt) nanoclay was added into CRMB binder and its inhibiting effect on the VOCs emission of the binder was investigated. Finally, the VOCs emission models for the CRMB and Mt-modified CRMB (Mt-CRMB) binders were established according to reasonable assumptions. The results indicated that the VOCs emission of CRMB binder was 3.2 times larger than that of the base binder. Due to its intercalated structure, the nanoclay can reduce the VOCs emission of CRMB binder by 30.6%. Especially, its inhibition effects on alkanes, olefins, and aromatic hydrocarbons were more significant. After finite element verification, the established model based on the Fick's second law can describe the emission behavior of CRMB and Mt-CRMB binders well. Overall, the Mt nanoclay can be used as an effective modifier to inhibit the VOCs emission of CRMB binder.

Urinary profile of PAHs and related compounds in women working in beauty salons

Polycyclic aromatic hydrocarbons (PAHs) are a group of chemical compounds which interest to human biological monitoring researches because of their potential carcinogenic, mutagenic, and teratogenic properties. However, the exposure of female beauticians to these contaminants is not well-reported. For biomonitoring of potential exposure of female cosmeticians to PAHs in beauty salons, urine samples were taken from cosmetologist women (n = 50.00) and housewives (n = 35.00) as the exposure group (EG) and control group (CG), respectively. Next, unmetabolized PAHs levels as well as the concentration of - 1-hydroxypyrene (1-OHP) were analyzed in these specimens. In addition, since benzene has some common source with PAHs, in this study t, t'-Muconic acid (TTMA) level was also determined as the metabolite and indicator of exposure to benzene. The results indicated a high detection frequency of the target compounds (PAHs, 1-OHP and TTMA) in the urine specimens of beauticians. The results also showed that there is a significant difference between the concentration of these pollutants in the urine specimens of the exposure and control groups. The median concentration of ΣPAHs, 1-OHP, and TTMA in the before exposure (BE) specimens collected from the exposure group were 337.42 ng/L, 593.92 ng/L, and 247.90 μg/L, respectively. However, a higher concentration of these contaminants was observed in the after exposure specimens with a median concentration of 423.29 ng/L, 745.03 ng/L, and 310.97 μg/L, respectively. In terms of contribution of PAHs compounds in total toxic equivalents, DahA, BaP, and IndP with 59.03, 28.73, and 2.86 % had the largest share. In this study, it was also observed that some kidney damage biomarkers as well as some oxidative stress injury biomarkers are positively and significantly correlated with the urinary values of ∑PAHs. Thus, it can be concluded that high health risks threaten the female beauticians regarding kidney injury and DNA oxidative stress.

Metabolomics for exposure assessment and toxicity effects of occupational pollutants: current status and future perspectives

INTRODUCTION

Work-related exposures to harmful agents or factors are associated with an increase in incidence of occupational diseases. These exposures often represent a complex mixture of different stressors, challenging the ability to delineate the mechanisms and risk factors underlying exposure-disease relationships. The use of omics measurement approaches that enable characterization of biological marker patterns provide internal indicators of molecular alterations, which could be used to identify bioeffects following exposure to a toxicant. Metabolomics is the comprehensive analysis of small molecule present in biological samples, and allows identification of potential modes of action and altered pathways by systematic measurement of metabolites.

OBJECTIVES

The aim of this study is to review the application of metabolomics studies for use in occupational health, with a focus on applying metabolomics for exposure monitoring and its relationship to occupational diseases.

METHODS

PubMed, Web of Science, Embase and Scopus electronic databases were systematically searched for relevant studies published up to 2021.

RESULTS

Most of reviewed studies included worker populations exposed to heavy metals such as As, Cd, Pb, Cr, Ni, Mn and organic compounds such as tetrachlorodibenzo-p-dioxin, trichloroethylene, polyfluoroalkyl, acrylamide, polyvinyl chloride. Occupational exposures were associated with changes in metabolites and pathways, and provided novel insight into the relationship between exposure and disease outcomes. The reviewed studies demonstrate that metabolomics provides a powerful ability to identify metabolic phenotypes and bioeffect of occupational exposures.

CONCLUSION

Continued application to worker populations has the potential to enable characterization of thousands of chemical signals in biological samples, which could lead to discovery of new biomarkers of exposure for chemicals, identify possible toxicological mechanisms, and improved understanding of biological effects increasing disease risk associated with occupational exposure.

Polycyclic aromatic hydrocarbon exposure and DNA oxidative damage of workers in workshops of a petrochemical group

The petrochemical industry has promoted the development of economy, while polycyclic aromatic hydrocarbons (PAHs) produced by the industry become the threat for environment and humans. Data on human occupational exposure in petrochemical industry are limited. In the present study, urinary hydroxylated PAH metabolites (OH-PAHs) and a biomarker of DNA oxidative damage (8-hydroxy-2'-deoxyguanosine (8-OHdG)) were measured in 546 workers of a petrochemical group in Northeast China, to investigate PAH exposure and related potential health risk. The concentrations of ∑₉OH-PAH in all workers were 0.25-175 μg/g Cre with a median value of 4.41 μg/g Cre. Metabolites of naphthalene were the predominant compounds. The levels of PAH metabolites were significantly different for workers with different jobs, which were the highest for recycling workers (13.7 μg/g Cre) and the lowest for agency managers (5.12 μg/g Cre). Besides, higher levels of OH-PAHs were usually found in males and older workers. There was a dose-response relationship between levels of 8-OHdG and ∑₉OH-PAHs (p < 0.01). No difference was observed in concentrations of 8-OHdG for workers of different gender or ages, work history as well as noise. Furthermore, workers simultaneously exposed to other potential pollutants and higher levels of ∑₉OH-PAH had significantly higher levels of 8-OHdG compared with those in the corresponding subgroups. Our results suggested that exposure to PAHs or co-exposure to PAHs and potential toxics in the petrochemical plant may cause DNA damage. We call for more researches on the associations among noise, chemical pollution and oxidative stress to workers in the real working environment.

The Investigation of Volatile Organic Compounds (VOCs) Emissions in Environmentally Friendly Modified Asphalt

Asphalt pavements are increasingly used in road engineering; however, the release of volatile organic compounds (VOCs) from asphalt can harm the environment and humans. In this study, different types of modifiers are added to 70# virgin asphalt to prepare environmentally friendly modified asphalt, and its performance is analyzed. Through the self-designed simple asphalt heating-emission collection and detection device, the inhibition effect of different types of modifier combinations on VOCs in the asphalt emmissions was explored. Then, VOCs emission curves of modified asphalt at different temperatures were studied, and finally the basic physical properties of the environmentally friendly modified asphalt were tested. The test results showed that the optimal modifier combination was 5% activated carbon and 3% surfactant, in which the VOCs and the peak value of asphalt heating emissions were only 1385 min·ppm and 86 ppm, respectively, which represented the best VOCs suppression effect of other groups. At the same time, the modified asphalt with optimal additives improved the high-temperature performance of 70# base asphalt and did not affect the storage stability.

The Use of Human Biomonitoring to Assess Occupational Exposure to PAHs in Europe: A Comprehensive Review

Polycyclic aromatic hydrocarbons (PAHs) are among the chemicals with proven impact on workers' health. The use of human biomonitoring (HBM) to assess occupational exposure to PAHs has become more common in recent years, but the data generated need an overall view to make them more usable by regulators and policymakers. This comprehensive review, developed under the Human Biomonitoring for Europe (HBM4EU) Initiative, was based on the literature available from 2008-2022, aiming to present and discuss the information on occupational exposure to PAHs, in order to identify the strengths and limitations of exposure and effect biomarkers and the knowledge needs for regulation in the workplace. The most frequently used exposure biomarker is urinary 1-hydroxypyrene (1-OH-PYR), a metabolite of pyrene. As effect biomarkers, those based on the measurement of oxidative stress (urinary 8-oxo-dG adducts) and genotoxicity (blood DNA strand-breaks) are the most common. Overall, a need to advance new harmonized approaches both in data and sample collection and in the use of appropriate biomarkers in occupational studies to obtain reliable and comparable data on PAH exposure in different industrial sectors, was noted. Moreover, the use of effect biomarkers can assist to identify work environments or activities of high risk, thus enabling preventive risk mitigation and management measures.

Towards environmental sustainability in the local community: Future insights for managing the hazardous pollutants at construction sites

Although various technologies are being developed in the construction industry, management technologies for achieving environmental sustainability in the local community are still lacking. As such, this study suggests future insights for the development of an automated intelligent environment management system for the promotion of environmental sustainability in the local community, through a systematic review of 1,707 relevant literature. The systematic review was conducted in two steps: (i) quantitative review: keyword co-occurrence and trend analysis; and (ii) qualitative review: a review on monitoring, evaluation, and improvement technologies. As a result, the research level related to the local-level pollutants (noise, vibration, and dust) was found to be quantitatively insufficient, and the limitations of the existing technologies for these pollutants were presented. Eventually, to overcome these limitations, new technologies and application strategies that can be applied to construction sites as future research roadmap to effectively manage the hazardous pollutants were proposed. Furthermore, an intelligent management system should be developed, and the management of environmental complaints is also necessary for environmental sustainability at the local level in the construction industry. As a fundamental study, this study could become a benchmark for future researches dealing with environmental sustainability and hazardous pollutants in the construction industry.

Towards a recommended biomonitoring strategy for assessing the occupational exposure of roofers to PAHs

The aims of this work were to assess the PAH exposure among roofers and to identify relevant biomarkers for monitoring occupational exposure. Several campaigns were conducted between 2004 and 2017, with 28 individual air samples and 240 urinary samples collected from 73 roofers. Seventeen parent PAHs and 14 urinary biomarkers, metabolites of pyrene (1-OHP), benzo(a)pyrene (3-OHBaP and TetraolBaP), naphthalene (1- and 2-naphtols), fluorene (1- 2- 3- 9-fluorenols) and phenanthrene (1- 2- 3- 4- 9-phenanthrols), were analysed. Three exposure groups were considered: soft-applied roofing using polymer-modified bitumen ("PMB"), hot-applied roofing using oxidized bitumen ("OB") and the tearing off of old roof coatings containing coal tar ("CT"). The PAHs containing 2-3 rings were much more abundant, and the highest airborne levels were observed in the "CT" group. The biomonitoring results were consistent with these results, with a large predominance of 2-3 ring PAH metabolites. 1-OHP, 3-fluorenol and 2-phenanthrol were better correlated with airborne levels and less influenced by smoking than the other metabolites. Conversely, 1-/2-naphtol levels were heavily influenced by smoking and not correlated with airborne naphthalene levels. Moreover, 3-OHBaP and TetraolBaP levels were very low when applying bitumen membranes, and much higher exposures were observed during tear-off activities. In this context, the recommended strategy for roofer biomonitoring should include 1-OHP, fluorenols and phenanthrols, as well as carcinogenic BaP metabolites (3-OHBaP or TetraolBaP) when evaluating the occupational exposure of roofers that are tearing off old roof coatings.