Bitumen Fumes Research Articles

Emission reduction agents: A solution to inhibit the emission of harmful volatile organic compounds from crumb rubber modified bitumen

Volatile organic compounds (VOCs) in bitumen fumes pose health risks to workers. Adding end-of-life tire crumb rubber (CR) to bitumen increases VOC emissions. To promote cleaner asphalt production, recycled materials like cementitious materials, activated carbon, zeolite, and geopolymers were incorporated into crumb rubber modified bitumen and explored as emission reduction agents (ERAs). Proton-transfer-reaction time-of-flight mass spectrometry was used to compare VOC emissions across blends. ERAs reduced emissions by at least 33%, with Portland cement, activated carbon, and geopolymer-based fly ash achieving up to 58%, 49%, and 48% reduction, respectively. Multivariable regression analyses showed that the BET surface area, BJH adsorption cumulative surface area, BJH desorption cumulative surface area, and average pore diameter of the ERAs were the predominant factors contributing to the reduction of VOC emissions.

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

BackgroundAsphalt 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. MethodsA 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. ResultsFume 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. ConclusionThe 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.

Parental occupational exposure to chemicals and risk of breast cancer in female offspring

ObjectivesParental exposure to chemicals at work has been hypothesized to be a potential predisposing factor for breast cancer in next generations. The objective of the present nationwide nested case-control study was to contribute with evidence to this area. MethodsWomen with primary breast cancer were identified using the Danish Cancer Registry and they were required to have information on either maternal or paternal employment history, which resulted in the inclusion of 5587 cases. For each case, 20 female cancer free controls were matched on year of birth using the Danish Civil Registration System. Employment history was linked to job exposure matrices to assess specific occupational chemical exposures. ResultsFor maternal exposures, we observed an association between ever exposure to diesel exhaust (OR = 1.13, 95% CI: 1.01–1.27) and exposure to bitumen fumes in the perinatal period (OR = 1.51, 95% CI: 1.00–2.26) and breast cancer in female offspring. Highest cumulative exposure to benzo(a)pyrene, diesel exhaust, gasoline and bitumen fumes was further indicated to increase the risk. Results further indicated a stronger association between diesel exhaust (OR = 1.23, 95% CI: 1.01–1.50) and benzo(a)pyrene exposure (OR = 1.23, 95% CI: 0.96–1.57) and estrogen receptor negative tumors than tumors with ER expression, while bitumen fumes seemed to elevate the risk of both hormonal subtypes. For paternal exposures, the main results did not indicate any associations with breast cancer in female offspring. ConclusionsOur study suggests an elevated breast cancer risk in daughters of women occupational exposed to some occupational pollutants, including diesel exhaust, benzo(a)pyrene and bitumen fumes. These findings need to be confirmed in future large-scale studies before any firm conclusions can be reached.

Chemical characterization and anaerobic treatment of bitumen fume condensate using a membrane bioreactor

Bitumen fume condensate (BFC) is a hazardous wastewater generated at asphalt reclamation and production sites. BFC contains a wide variety of potentially toxic organic pollutants that negatively affect anaerobic processes. In this study, we chemically characterized BFC produced at an industrial site and evaluated its degradation under anaerobic conditions. Analyses identified about 900 compounds including acetate, polycyclic aromatic hydrocarbons, phenolic compounds, and metal ions. We estimated the half maximal inhibitory concentrations (IC50) of methanogenesis of 120, 224, and 990 mgCOD·L−1 for three types of anaerobic biomass, which indicated the enrichment and adaptation potentials of methanogenic biomass to the wastewater constituents. We operated an AnMBR (7.0 L, 35 °C) for 188 days with a mixture of BFC, phenol, acetate, and nutrients. The reactor showed a maximum average COD removal efficiency of 87.7 ± 7.0 %, that corresponded to an organic conversion rate of 286 ± 71 mgCOD−1·L−1d−1. The microbial characterization of the reactor’s biomass showed the acetoclastic methanogen Methanosaeta as the most abundant microorganism (43 %), whereas the aromatic and phenol degrader Syntrophorhabdus was continuously present with abundances up to 11.5 %. The obtained results offer the possibility for the application of AnMBRs for the treatment of BFC or other petrochemical wastewater.

Sample Preparation and Analytical Methods for Identifying Organic Compounds in Bituminous Emissions.

Bitumen is a major construction material that can emit harmful fumes when heated. These fumes pose health risks to workers and communities near construction projects or asphalt mixing plants. The chemical complexity of bitumen fumes and the increasing use of additives add to the difficulty of analytically quantifying the harmful chemicals emitted using a single technique. Research on bitumen emissions consists of numerous sample preparation and analytical methods. There are a range of considerations to be made when deciding on an appropriate sample preparation method and instrumental configuration to optimise the analysis of specific organic contaminants in emissions. Researchers investigating emissions from bituminous materials may need to consider a range of analytical techniques to quantify harmful chemicals and assess the efficacy of new additives. This review summarises the primary methodologies for sample preparation and analytical techniques used in bitumen research and discusses future challenges and solutions.

Pulmonary Functions and Work-Related Musculoskeletal Disorders of Road Construction Workers of West Bengal, India

Introduction: Road paving construction workers are exposed to bitumen, asphalt, and other aliphatic amines. They are also exposed to high temperatures and dust during the processing of asphalt production and transport of hot asphalt and bitumen to the working site. Bitumen fumes and asphalt produce respiratory irritations and shortness of breath in asphalt workers. Thus, the purpose of this study was to assess the respiratory impairment of asphalt workers on exposure to bitumen fumes and to assess cardiovascular stress on exposure to high temperatures and heavy workload. Methods: This cross-sectional study has been made on 32 asphalt workers and 20 control group workers of Kolkata city of West Bengal and its surrounding. Anthropometric parameters, blood pressure, and heart rate were measured by standard procedure. Respiratory parameters were taken by Digital Spirometer (Spirovit SP1) and respiratory symptoms & musculoskeletal problems were recorded by a standard questionnaire. Results: The study indicated that prolong exposure to bitumen fumes may enhance the risk of lung impairment by reduction of all respiratory parameters (p< 0.05-0.001). Smoking habits and the reluctance to use protective gadgets among asphalt workers increase the risk of respiratory distress.22% of workers reported chest tightness, 20% had Chronic Bronchitis and10% suffered from Bronchial asthma. The maximum percentage of Paver operators showed Chest tightness (83.33%), Chronic Bronchitis (100%) and Bronchial asthma(66.66%). Musculoskeletal Disorder(MSD) among Paver operators was maximum(33.3-50%). Odds ratio values of the prevalence of respiratory disorder and MSD with >10years of exposure to bitumen fumes vary from 2-4.5. Exposure to high temperature and heavy workload, mainly among asphalt strippers and paver operators might be the reason for higher heart rate. The awkward working posture might be the cause of musculoskeletal disorders among them. Conclusion: The use of appropriate respiratory protection and the introduction of modern equipment and technologies can reduce the emission of bitumen fumes to protect the health of asphalt workers.

Recycled plastic modified bitumen: Evaluation of VOCs and PAHs from laboratory generated fumes

A key aspect when investigating the use of recycled plastics in bitumen relates considerably to the issues relating to occupational, health and safety for humans and the environment from a fuming and emissions perspective. This research investigates laboratory-generated fumes in the forms of volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs) generated from producing polymer modified bitumen using five different types of recycled plastics. A comparative analysis of recycled plastic modified bitumen fumes was conducted based on a series of optimized parameters, including working temperatures (160 °C, 180 °C and 200 °C) and polymer contents (1%, 2%, 4% and 6% by weight of bitumen) against neat bitumen and polymer-modified bitumen. Forty-eight volatile organic compounds (VOCs) and sixteen polycyclic aromatic hydrocarbons (PAHs) were quantified using gas chromatography–mass spectrometry (GC–MS). The results from the comparative analysis revealed that the incorporation of recycled plastics could reduce overall emissions from both VOCs and PAHs perspectives. The reduction in emissions can be attributed to the enhancement in thermal stability of the bitumen blend when recycled plastics are added. The reduction rate is heavily dependent on the type and source of recycled plastics used in the blending process. Furthermore, a specific compound concentration analysis of the top-four weighted compounds emitted reveals that the total concentration of emissions can be deceiving as specific compounds can spike when adding recycled plastics in bitumen despite a reduction trend for the overall concentration.

Organic Compounds Evaluation from Fumes Generated in Laboratory by Bio-recycled Asphalt Mixtures

Abstract Using bio-binder and bio-additives as recycling agents for asphalt mixtures with high-content of reclaimed asphalt (RA) is proving to be feasible. It is still not clear whether this combination might provide new known hazardous emissions from airborne binder fumes. The health hazard related to airborne bitumen fume generation is primarily relevant for paving crews, whereas there is little opportunity for exposure for asphalt plant workers. In this study, measurements of gaseous organic compounds from airborne binder fumes of selected bio-asphalt mixtures have been measured during the laboratory mixing process by using a thermo-mixer equipped with a chimney at University Gustave Eiffel. Parameters studied are the binder nature, mix formula, and mixing temperatures. Results show that generally combining bio-based materials and RA is as safe as using conventional bitumen and RA; however, thanks to this approach, it was possible to identify a strong link between bituminous materials’ composition and their emission potential.

Associations of Bitumen Fumes with Lymphocyte Subsets and Cytokines Expression in the Peripheral Blood of Exposed Workers

The present study aimed to investigate the distribution of lymphocyte subsets and cytokines expression in the peripheral blood of bitumen fumes-exposed workers. In this study, 129 workers from molding and roasting workshops were recruited as the exposed group and 99 office and quality inspection staff were chosen as the control. The polycyclic aromatic hydrocarbons (PAHs) levels of bitumen fumes in individual and fixed-point air samples and the urinary levels of 1-hydroxypyrene (1-OH-P), 1-hydroxynaphthols (1-OH-N) and 2-hydroxynaphthols (2-OH-N) in workers were measured using High Performance Liquid Chromatography. The lymphocyte subsets and serum cytokines concentrations were analyzed by flow cytometry and cytometric bead array, respectively. The median values of PAHs were 0.08 mg/m3 for permissible concentration-time weighted average and 0.12 mg/m3 for permissible concentration-short term exposure (PC-STEL) in molding and roasting workshops, which were higher than that in the control area (< 0.01 mg/m3). Multivariate linear regression models were used to adjust for influential covariates, including age, gender, work age, smoking status, and alcohol consumptions. After adjusting for these covariates, we compared levels of urinary PAHs metabolites, the percentages of lymphocyte subsets, and serum cytokines concentrations between the two groups. The 1-OH-P, 1-OH-N, and 2-OH-N levels in the urine of bitumen fumes exposed workers were significantly higher than that in the controls (P < 0.05). Compared with the control group, the percentage of the natural killer (NK) cell (CD56+ cell) was significantly increased in the exposed group (P < 0.001). There was a significant decrease in the percentages of CD3+ T cell, CD4+ T cell, and CD8+ T cell in the exposed group compared to the control (P < 0.001). The serum levels of interleukin-1β (IL-1β) and IL-6 in bitumen fumes exposed workers were significantly higher than that of the controls (P < 0.05). Moreover, positive correlations were observed between the serum levels of IL-1β, IL-6, and urinary 1-OH-P levels in bitumen fumes-exposed workers, respectively (P < 0.05). There were no significant differences in the serum levels of IL-8, tumor necrosis factor-α (TNF-α), macrophage inflammatory protein-1β (MIP-1β) and monocyte chemotactic protein-1 (MCP-1) between the exposed group and the control group (P > 0.05). Our study suggested that low dose of bitumen fumes exposure could decrease the percentage of T cell, increase the percentage of NK cell and stimulate the release of serum IL-1β and IL-6 in the peripheral blood of exposed workers. The serum levels of IL-1β and IL-6 were positive correlated with the urinary 1-OH-P levels in bitumen fumes exposed workers. These results may inform the search for potential effective biomarkers and provide evidences for early health monitoring in workers occupationally exposed to bitumen fumes.

Investigation on the use of a novel chemical bitumen additive with reclaimed asphalt and at lower mix production and construction temperatures: a case study

New regulations on bitumen fumes and aerosols, along with increasing traffic and climatic loads on highways, demand innovative construction materials. In this investigation, a novel isocyanate-based bitumen additive was used to pave 0.5 km of an asphalt binder layer with 50% reclaimed asphalt at 20-30°C below hot mix asphalt (HMA) temperatures, in Germany. During construction, bitumen fumes and aerosols were measured for both reference and modified asphalt mixtures. The reference mixture was paved using a similar mixture but with standard polymer modified bitumen, at standard HMA temperatures. For the investigation, a bitumen 70/100 was modified with 2.0% by wt with this novel isocyanate-based additive in an in-line procedure directly at an asphalt mixing plant without affecting production times. Bitumen and asphalt tests were conducted in the laboratory, on asphalt gathered from the construction site. Due to the temperature reduction, the emissions could be considerably reduced, while maintaining comparable asphalt performance..

Prenatal developmental toxicity studies on fumes from bitumen in the rat

The prenatal developmental toxicity of bitumen fume was tested by nose-only inhalation in the rat. The fumes for exposure were collected from the headspace of a storage tank filled with a bitumen corresponding in composition to an anticipated worst-case occupational exposure. The composition of these fumes was compared to actual paving site fumes to ensure its representativeness for workplace exposures. In a dose-range-finding study male and female rats were exposed to 0, 103, 480 or 1043 mg/m3 of fume (as total organic mass), for 6 h/day during 20 days post conception (p.c.). Dose-related effects on body weight and lungs were observed in the mid- and high-dose groups. In the main study, dams were exposed to 0, 52, 151 and 482 mg/m3 of fume, for 6 h/day during 19 days p.c. The maternal NOAEL was 52 mg/m³. In the high-dose group treatment-related effects on body weight (gain), food consumption, lung weights, and histopathological changes in lungs and larynx were observed. In the mid-dose group only histopathological changes in the larynx and lungs were found. The NOAEL for prenatal developmental toxicity was 151 mg/m³ based on reduced fetal weight in the high-dose group (482 mg/m³). However, these changes are most likely a consequence of the maternal toxicity, in particular the reduction of maternal body weight gain by 26 % as compared to control. Nose-only exposure to bitumen fumes in concentrations up to 482 mg/m³ from days 1–19 p.c. did not induce any significant fetal anomalies.

VOC Emission Analysis of Bitumen Using Proton-Transfer Reaction Time-Of-Flight Mass Spectrometry.

Bitumen is one of the most important materials used in roads. During asphalt pavement construction, workers can be affected by emissions, such as volatile organic compounds (VOCs), when bitumen is heated. Therefore, it is crucial to correctly identify and measure VOCs. This paper presents a novel, promising method to determine VOC emissions. The proposed method offers a way to standardize routine measurements on a lab scale, enabling reliable comparison across bitumen types and their modifications or additives. A proton-transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) was used to monitor VOC emissions from commercial unmodified bitumen and crumb rubber modified bitumen (CRMB) with heating of up to 180 °C. Results confirmed that the temperature range of 160–180 °C is a highly influential factor for VOC emissions from heated commercial bitumen and particularly CRMB. A significant increase in alkane and aromatic emission was detected when the binders were heated to 180 °C. Sulfur-containing VOCs were almost nonexistent for the base bitumen fumes, while a significant increase was detected in the fumes when two different types of CR were added to the bitumen, even at 120 °C. The additional CR in the bituminous binder contributed to the potentially harmful VOC emission of benzothiazole, which belongs to the class of sulfur-containing compounds. The concentration of benzothiazole was 65%, 38%, and 35% higher for CR1 in comparison to CR2 at 140, 160, and 180 °C, respectively. It is clear from the results that this method allows different bitumen sources or modifications to be quickly analyzed and their VOC emissions cross-compared. If adopted and confirmed further, the method could offer the asphalt industry a viable solution to monitor VOC emissions by analyzing samples in real time at different steps of the production process.

A social license to operate: pre-mining effects and activities perspective

Abstract This research proposes a new approach to recommend a responsible mining guideline on how to secure a social license to operate in Ondo state, Nigeria for oil sands mineral resources taking into account the bituminous natural effects. This is the case of bituminous oil sands in Southern Nigeria, where warm weather can induce the emission of natural bitumen fumes. Because this emission may bring occupational exposure to the local communities, mining is perceived to be an opportunity for both social-economic improvement but also an efficient approach to reduce exposure to bitumen fumes. The study investigates the importance of the perception of the society about responsible mining practices in establishing a social license for a mining operation. The results of the investigation include an appraisal of the social status, living conditions of the communities, effects of pre-mining activities and the natural impacts of bitumen from oil sand on the community. The conclusions are that the bituminous natural effects on the communities can facilitate the approval of SLO, if the company can fulfil its promises, as mining is perceived to be a welcome solution to the problems posed. In addition, the mining company must also be transparent with the community as this changes the perception of society about responsible mining practices and help in establishing SLO.

Percutaneous Absorption of Polycyclic Aromatic Compounds from Fume Condensates of Paving and Built Up Roofing Asphalts

Paving and roofing workers can be exposed to low levels of polycyclic aromatic compounds (PACs) while working with asphalt at elevated temperatures via both the inhalation and dermal routes. Inhalation exposure date are readily available. However, dermal information is more complicated and not as well-studied. Here we evaluate condensed fumes from four paving and four BURA asphalts for percutaneous absorption through human skin using in vitro studies. Test materials included eight asphalt (bitumen) fume condensates (AFCs) collected from the headspace above four paving and four Type III built up roofing asphalt (BURA) tanks, each proven to match worker breathing zone exposures. Sections of human cadaver skin were sliced with a dermatome to a thickness of 250–350 μm, one-inch circular pieces were mounted in Franz diffusion cells epidermis side up. Receptor fluids were sampled at intervals over 48 hr and the aliquots analyzed for PACs using HPLC with fluorescence detection to determine the dermal flux rates of anthracene, fluoranthene/pyrene, and total 3-6 ring PACs.For paving/BURA AFCs, respectively, the average (N = 4) concentrations (μg/g) were: anthracene, 50.6 (SD = 14)/27.2 (SD = 28); fluoranthene/pyrene, 66.5 (SD = 47)/83.2 (SD = 100); Ʃ3-6 ring PACs, 833 (SD = 302)/2191 (SD = 240). Dermal flux rates (ng/cm2/hr) were: anthracene, 4.4 (SD = 1.1)/1.9 (SD = 2.0); fluoranthene/pyrene, 3.8 (SD = 2.8)/3.6 (SD = 5.0); Ʃ3-6 ring PAC, 35 (SD = 14)/21 (SD = 15). The estimated dermal flux of benzo[a]pyrene B[a]P in paving AFCs ranged from 0.0006 to 0.007 ng/cm2/hr and for BURA AFCs from 0.016 to 0.19 ng/cm2/hr. The averaged experimentally determined permeability coefficient (Kp) for anthracene for all eight samples was 0.90 ± 0.13 × 10−4 cm/hr (95% CI). Results show limited absorption of PACs across the skin in AFCs under the most conservative conditions (occluded/infinite dose). Dermal flux results can be used to support dermal exposure and risk assessments for asphalt emissions.

Bituminous Conglomerates Industrial Production. Assessment of Odour Emissions in View of Regional Guidelines Publication

In Italy the production of bituminous conglomerates (BC) has no specific guidelines for odour emissions. Bitumen fumes contain particulates, hydrocarbons (VOC) and hydrogen sulphide (H2S) and the quantity of fumes depends on bitumen quality, the handling and storage of the bitumen and inert material. Different VOC formation, including odorants, depends on various parameters such as the asphalt temperature, the asphalt oxidation, and the humidity of air, and large variations are observed under different operational parameters. Currently authorizations and permits for binder and hot mix plants are generally limited to pollutants in stack emissions, like particulate matter (PM), total hydrocarbons (THC) and polycyclic aromatic hydrocarbons (PAH). Like other industrial activities, BC production plants are facing increasing difficulty in coexistence with residents in the vicinity of production facilities due to odour emissions (Palmiotto et al., 2014).Production plants use different technologies and odour emissions occur not only through the stack, were fumes coming from hot mixing of a bituminous binder with mineral stone sand and filler are emitted, but also from diffuse uncontrolled emissions, due to storage and handling operations of bitumen at high temperatures.In this work we present data from different monitoring campaigns focussed on odour emissions from hot mix asphalt (HMA) manufacturing facilities, that will be used to quantitatively describe this specific industry sector or category, i.e. a group of similar emitting sources. The final objective will be the definition of emission factors regarding HMA odour emissions, possibly also with a specific odour emission factor estimated per tons of product in view of the possible publication of Lombardy Regional Guidelines on HMA odour emissions characterization and mitigation.

PAHs emissions by 12 Brazilian bitumens: procedure and results

In the last few years, there has been a great focus on human health and improving working conditions. Within this context, it is necessary to study the impact of the highway construction on the quality of life of workers and the environment. This paper aims to study polycyclic aromatic hydrocarbons (PAHs) emission from different bitumens commercialised in Brazil (conventional, modified by polymer or rubber and natural asphalt). The bitumens were submitted to conventional (Brazilian specifications) and rheological (SUPERPAVE classification) tests. The most usual application method is as a hot mixture. When heated, the bitumen releases volatile species and solid particles carried by gases, and this mixture is called bitumen emissions. In this fume, there are organic substances (PAHs), some of which may be carcinogenic. Therefore, the fume emitted during bitumen heating is harmful to health and should be considered both from the environmental sustainability and the worker health points of view. PAH studies were done alongside with other studies where the bitumen and the emission of some PAHs were correlated, which were measured through an experimental apparatus that generates and collects the bitumen fume. The equipment used was a nominated extraction and collection device (ECD) and the tests were conducted on laboratory benches. The fumes were collected in ECD and analysed by liquid chromatography–mass spectrometry to quantify the amount of emitted PAHs. From the research, it was possible to verify if bitumens with different behaviours at paving, from the perspective of sustainability and different impacts to the environment and human health. These emissions have an impact on health and the environment, which require further understanding.

Polycyclic aromatic hydrocarbons (PAHs) skin permeation rates change with simultaneous exposures to solar ultraviolet radiation (UV-S)

Road construction workers are simultaneously exposed to two carcinogens; solar ultraviolet (UV-S) radiation and polycyclic aromatic hydrocarbons (PAHs) in bitumen emissions. The combined exposure may lead to photogenotoxicity and enhanced PAH skin permeation rates. Skin permeation rates (J) for selected PAHs in a mixture (PAH-mix) or in bitumen fume condensate (BFC) with and without UV-S co-exposures were measured with in vitro flow-through diffusion cells mounted with human viable skin and results compared. Possible biomarkers were explored. Js were greater with UV-S for naphthalene, anthracene, and pyrene in BFC (0.08–0.1 ng/cm2/h) compared to without (0.02–0.26 ng/cm2/h). This was true for anthracene, pyrene, and chrysene in the PAH-mix. Naphthalene and benzo(a)pyrene (BaP) in the PAH-mix had greater Js without (0.97–13.01 ng/cm2/h) compared to with UV-S (0.40–6.35 ng/cm2/h). Time until permeation (Tlags) in the PAH-mix were generally shorter compared to the BFC, and they ranged from 1 to 13 h. The vehicle matrix could potentially be the reason for this discrepancy as BFC contains additional not identified substances. Qualitative interpretation of p53 suggested a dose-response with UV-S, and somewhat with the co-exposures. MMP1, p65 and cKIT were not exploitable. Although not statistically different, PAHs permeate human viable skin faster with simultaneous exposures to UV.

Cancer Risk Associated With Exposure to Bitumen and Bitumen Fumes

To evaluate whether cancer risks are increased among bitumen (asphalt) workers. Systematic review and meta-analysis of cancer risks (lung, upper aerodigestive tract (UADT), esophagus, bladder, kidney, stomach, and skin) and bitumen exposure. Certainty in the epidemiological evidence that bitumen-exposed workers experience increased cancer risks was rated using Grading of Recommendations Assessment, Development and Evaluation criteria. After excluding lower-quality studies, lung cancer risks were not increased among bitumen-exposed workers (meta-relative risk [RR] 0.94, 95% CI 0.74 to 1.20, eight studies). Increased risks of UADT and stomach cancers were observed (meta-RR 1.31, 95% CI 1.03 to 1.67, 10 studies and meta-RR 1.29, 95% CI 1.03 to 1.62, seven studies, respectively). Except for lung cancer, evidence for increased cancer risks among bitumen-exposed workers was judged to be of low certainty, due to inadequate exposure characterization and unmeasured confounders (coal tar exposure, smoking, and alcohol consumption).

Detection of Benzo[a] pyrenediol epoxide-DNA adducts in White Blood Cells of Asphalt Plant Workers in Syria

Background: Benzo [a] pyrene is considered a classic DNA-damaging carcinogen and is a lead compound of polycyclic aromatic hydrocarbons.B [a] Pis metabolically activated by cytochrome P450 enzymes to formation electrophilic metabolites such as epoxides. These epoxides might bind to DNA and produce DNA-adducts. ELISA method is used for determination of DNA adducts of benzo [a] pyrenediolepoxide (BPDE). Objectives: The aim of this study was to evaluate exposure to B [a] P in asphalt plant workers by measuring the BPDE-DNA adducts in their peripheral white blood cells (WBC), which are considered biological markers for exposure risk assessment. MaterialandMethods: In this study, the levels of BPDE-DNA adducts were measured in DNA samples of WBC obtained from asphalt plant workers in Syria and compared to those measured from a control group. The measurement was performed using BPDE-DNA Adducts ELISA kit. The sample size was determined to be 50 with 25 asphalt plant workers and 25 healthy volunteers with no occupational exposure to Benzo [a] pyrene. Results: BPDE-DNA adducts were detected in WBC of 11 asphalt plant workers with concentrations ranging between 0 and 2.75 ng/ml and only one individual in the control group with concentration of 0.75 ng/ml. These results indicate a significant positive relationship betweenexposure toB [a] P through the bitumen fumes (working in asphalt plant) and formation of BPDE-DNA adducts. Conclusions: BPDE-DNA adducts area potential biomarker for PAHs exposure and likely helpful indicator of PAH-induced DNA damage.

The Relations between Polycyclic Aromatic Hydrocarbons Exposure and 1-OHP Levels as a Biomarker of the Exposure.

Polycyclic aromatic hydrocarbons (PAHs) are the products of incomplete combustion or pyrolysis of various organic materials. Their ubiquity in the environment leads to measurable levels of exposure. However, the exposure varies strongly between different regions in Europe. Some PAHs with four or more rings are suspected to be human carcinogens. Therefore, the occupational and/or environmental exposure to PAHs may cause a significant health risk. The aim of the study was to evaluate current levels of PAH exposure in defined groups of workers. The industrial sites selected in this survey involved PAHs originating from coal tar pitch, carbon black, bitumen, and rubber fumes. Based on the historical data, the sites were expected to exhibit quantifiable levels of exposure to PAHs. The total study population consisted of 139 persons: 108 workers (85 males and 23 females) workers were occupationally exposed in aluminium production, the production of graphite electrodes, road construction, or the rubber forming industry and 31 control individuals in two groups. The highest concentrations – 8-hour time-weighted average (TWA) levels (sum of 16 components according to the EPA list), as expected, were found in the aluminium production plant (55.15 µg.m−3) and production of graphite electrodes (54.25 µg.m−3). The lowest concentrations were found in personal air samples of road construction workers (1.93 µg.m−3). The concentrations of 1-hydroxypyrene as a pyrene metabolite (1-OHP) in the urine of the exposed group of workers were found in levels 0.74 µmol.mol−1 creatinine before the exposure and 2.27 µmol.mol−1 creatinine after the exposure (arithmetic mean values). 1-OHP concentrations in post-shift urine samples were highly correlated with the total airborne PAHs concentrations and pyrene concentrations in air. The correlation coefficients (rS) between 1-OHP concentration and pyrene or total PAHs in air were 0.710 and 0.752 (p < 0.05). This statistical analysis confirmed the effect of the occupational exposure to PAHs and pyrene on body burden in workers. However, a modifying effect of gender, smoking habits, dietary intake, genetically modified metabolism, and the use of medication on the toxicokinetics of pyrene was not determined as significant. Based on the results a strong correlation between the concentration of 1-OHP in urine as an exposure biomarker and the concentration of pyrene or PAH was affirmed.