Biomonitoring of styrene occupational exposures: Biomarkers and determinants.

INTRODUCTION: High styrene exposures are still experienced in various occupational settings, requesting regular exposure assessments. The aims of this study were to study occupational exposures in various industrial sectors and to determine factors influencing styrene urinary metabolites levels. METHODS: Biomonitoring was conducted in 141 workers from fiberglass-reinforced plastic (FRP) manufacture, thermoplastic polymers production, vehicle repair shops and cured-in-place pipe lining (CIPP). Urinary styrene (StyU) as well as Mandelic (MA) / Phenyglyoxylic Acids (PGA) were quantified at the beginning and at the end of week, and multivariate linear regression models were used. RESULTS: StyU levels revealed very low, rarely exceeding 3 µg.L-1. Highest concentrations of MA + PGA were observed in FRP sector, with levels reaching up to 1100 mg.g-1 of creatinine. Factors influencing end-of-week MA + PGA concentrations were levels at the beginning of week, open molding processes, proximity to the emission source, respiratory protection, styrene content in raw materials. Elevated levels were also observed during CIPP process, whereas thermoplastic injection and vehicle repair shop workers exhibited much lower exposures. CONCLUSIONS: Intervention on process (decreasing styrene proportion, using closed molding), protective equipment (local exhaust ventilation, respiratory protection) and individual practices (stringent safety rules) are expected to decrease occupational exposures. Urinary MA + PGA remain the most appropriate biomarkers for occupational biomonitoring.

Exporisq-HAP database: 20 years of monitoring French occupational exposure to polycyclic aromatic hydrocarbon mixtures and identification of exposure determinants.

BACKGROUND: Millions of workers are exposed to polycyclic aromatic hydrocarbons (PAHs), a well-known family of carcinogens, but occupational exposure data about PAH mixture compositions are scarce. OBJECTIVES: To provide a detailed picture of airborne PAH exposures encountered in the French industrial landscape over the previous 20 years and to identify determinants driving exposures. METHODS: Results from 1643 airborne samples of 16 gaseous and particulate PAHs implemented into the Exporisq HAP database from 1995 to 2014 were used to describe exposure levels and aerosol chemical composition in many industries and activities. Compliance of benzo[a]pyrene (BaP) levels with several existing occupational exposure limits for long-term exposure was assessed. RESULTS: BaP levels were lower than those reported in the literature, but the level and composition of PAH mixtures were highly variable between and within industries. Numerous exposure determinants (e.g., product composition, type and temperature of process, ventilation and confinement) were assumed to explain these differences. The highest levels were found in industries using products derived from coal (aluminum, silicon, and coke production, manufacturing of carbon products and foundries), with mean BaP levels up to 23 times higher than the French recommended value of 150 ng/m3. Forty-seven percent of the occupational activities exceeded this value. Conversely, exposures resulting from petroleum-derived products were relatively low. CONCLUSIONS: As health effects depend on PAH levels but also on the composition of the mixture, exposure assessments must characterize the entire mixtures and record specific determinants to define homogeneous exposure groups and to accurately assess health risks.

Occupational exposure to polycyclic aromatic hydrocarbons: relations between atmospheric mixtures, urinary metabolites and sampling times.

PURPOSE: Occupational exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed by either air monitoring or biomonitoring using urinary 1-hydroxypyrene (1-OHP) or 3-hydroxybenzo(a)pyrene (3-OHBaP). The aim of this study was to understand the links between atmospheric PAHs and urinary metabolites, in order to improve the biomonitoring strategy for assessing carcinogenic risk. METHODS: Personal air sampling for pyrene and BaP measurements, and urines for 1-OHP and 3-OHBaP analyses of seven workers from electrode production plant were collected every day of the working week. RESULTS: High variability of atmospheric levels between activities and between days was observed, especially for gaseous pyrene. No correlation was found between urinary metabolites: 1-OHP maximum levels occurred for "electrode extrusion" activity; those of 3-OHBaP occurred for "raw materials dispatcher." Sixty percentage of 3-OHBaP maximum levels were observed in urines collected at the beginning of shift the last workday. Those of 1-OHP occurred at different sampling times, depending on the gaseous pyrene levels (not stopped by P3 respirators). Dermal absorption of PAHs was confirmed by significant effect of particulate pyrene on 1-OHP in the samples collected the morning of the following day (p < 0.02, n = 25). CONCLUSIONS: Lack of correlation between metabolites concentrations emphasizes the non-relevance of 1-OHP, from a non-carcinogenic gaseous and particulate compound, and the great interest of 3-OHBaP, from carcinogenic BaP. Its slower urinary elimination prevents the risk of exposure underestimation, and urinary analysis should be performed at the beginning of shift the end of working week, especially in case of high exposure variability.

Relevance of urinary 3-hydroxybenzo(a)pyrene and 1-hydroxypyrene to assess exposure to carcinogenic polycyclic aromatic hydrocarbon mixtures in metallurgy workers.

OBJECTIVES: In metallurgy, workers are exposed to mixtures of polycyclic aromatic hydrocarbons (PAHs) in which some compounds are carcinogenic. Biomonitoring of PAH exposure has been performed by measuring urinary 1-hydroxypyrene (1-OHP), a metabolite of pyrene which is not carcinogenic. This study investigated the use of 3-hydroxybenzo(a)pyrene (3-OHBaP), a metabolite of benzo(a)pyrene (BaP) which is the main carcinogenic component in PAHs, to improve carcinogen exposure assessment. METHODS: We included 129 metallurgy workers routinely exposed to PAHs during working hours. Urinary samples were collected at three sampling times at the beginning and at the end of the working week for 1-OHP and 3-OHBaP analyses. RESULTS: Workers in anode production showed greater exposure to both biomarkers than those in cathode or silicon production, with respectively, 71, 40, and 30% of 3-OHBaP concentrations exceeding the value of 0.4 nmol mol(-1) creatinine. No difference was observed between the 3-OHBaP levels found at the end of the penultimate workday shift and those at the beginning of the last workday shift. Within these plants, the 1-OHP/3-OHBaP ratios varied greatly according to the workers' activity and emission sources. Using linear regression between these two metabolites, the 1-OHP level corresponding to the guidance value for 3-OHBaP ranged from 0.7 to 2.4 µmol mol(-1) creatinine, depending on the industrial sector. CONCLUSIONS: This study emphasizes the interest of monitoring urinary 3-OHBaP at the end of the last workday shift when working week exposure is relatively steady, and the irrelevance of a single guideline value for 1-OHP when assessing occupational health risk.