Occupational exposure to styrene in the fibreglass reinforced plastic industry: Comparison between two differentmanufacturing processes

INAIL-Settore Ricerca-Dipartimento di Medicina del Lavoro, Monteporzio Catone (RM), Italy.
La Medicina del lavoro (Impact Factor: 0.55). 09/2012; 103(5):402-12.
Source: PubMed


Styrene is used in manufacturing fiberglass reinforced plastics: and occupational exposure was related to neurotoxicology and genotoxicity. The sum of the metabolites mandelic and phenylglyoxylic acids is the ACGIH biomarker for occupational exposure with a BEI of 400 mg/g of creatinine in end shift urine corresponding to a airborne styrene concentration of 85 mg/m3. There are two main molding processes, open and closed, the last more effective at controlling worker's styrene exposure.
To compare the open molding process to the compression of fiber reinforced resin foils, a kind of closed molding, monitoring the styrene exposure of workers in two production sites (A and B).
Environmental Monitoring was carried out by Radiello samplers and Biological Monitoring by means of the determination of MA and PGA with HPLC/MS/MS in 10 workers at Site A and 14 at Site B.
The median values for styrene exposure resulted 31.1 mg/m3 for Site A and 24.4 mg/m for Site B, while the medians for the sum of the two metabolites in the end shift urine were 86.7 e 33.8 mg/g creatinine respectively. There is a significant linear correlation between personal styrene exposure and the excretion of styrene metabolites (R = 0.74).
As expected the exposure markers of the workers of the two production sites resulted higher in the open process. The analytical results of both environmental and biological monitoring were all below the occupational exposure limits, confirming the efficacy of the protective devices.

Download full-text


Available from: Giovanna Tranfo, May 12, 2014
  • Source
    • "The MA and PGA quantitative analysis was carried out according to Tranfo et al. (2012). Briefly, 10 mL urine sample was diluted with 10 mL of 2% acetic acid, spiked with 100 mL of internal standards (MA-D5 and PGA-D5) solution and injected into the HPLC–MS/MS system (API 4000, AB Sciex, MA, USA). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Styrene exposure is still present in different occupational settings including manufacture of synthetic rubber, resins, polyesters and plastic. The aim of this work was to investigate the effects of polymorphic genes CYP2E1, EPHX1, GSTT1, and GSTM1 on the urinary concentrations of the styrene metabolites Mandelic Acid (MA), Phenylglyoxylic Acid (PGA) and on the concentration ratios between (MA+PGA) and urinary styrene (U-Sty) and airborne styrene (A-Sty), in 30 workers from two fiberglass-reinforced plastic manufacturing plants and 26 unexposed controls. Personal air sampling and biological monitoring results revealed that sometimes exposure levels exceeded both the threshold limit value (TLV) and the biological exposure index (BEI) suggested by the American Conference of Governmental Industrial Hygienists. A significantly reduced excretion of styrene metabolites (MA+PGA) in individuals carrying the CYP2E1*5B and CYP2E1*6 heterozygote alleles, with respect to the homozygote wild type, was observed only in the exposed group. A reduction was also detected, in the same group, in subjects carrying the slow allele EPHX1 (codon 113), through the lowering of (MA+PGA)/Urinary Styrene concentration ratio. In addition, the ratio between MA+PGA and the personal airborne styrene concentration appeared to be modulated by the predicted mEH activity, in the exposed group, as evidenced by univariate linear regression analysis. Our results confirm some previous hypotheses about the role of the polymorphism of genes coding for enzymes involved in the styrene detoxification pathway: this may significantly reduce the levels of excreted metabolites and therefore it must be taken into account in the interpretation of the biological monitoring results for occupational exposure. Copyright © 2015. Published by Elsevier Ireland Ltd.
    Toxicology Letters 01/2015; 233(2). DOI:10.1016/j.toxlet.2015.01.002 · 3.26 Impact Factor
  • A Mutti ·

    La Medicina del lavoro 10/2012; 103(5):413-6. · 0.55 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The ototoxic effect of the exposure to styrene is evaluated, also in the presence of simultaneous exposure to noise, using otoacoustic emissions as biomarkers of mild cochlear damage. Transient-evoked and distortion product otoacoustic emissions were recorded and analyzed in a sample of workers (15 subjects) exposed to styrene and noise in a fiberglass manufacturing facility and in a control group of 13 non-exposed subjects. Individual exposure monitoring of the airborne styrene concentrations was performed, as well as biological monitoring, based on the urinary concentration of two styrene metabolites, the Mandelic and Phenylglyoxylic acids. Noise exposure was evaluated using wearable phonometers, and hearing loss with pure tone audiometry. Due to their different job tasks, one group of workers was exposed to high noise and low styrene levels, another group to higher styrene levels, close to the limit of 20 ppm, and to low noise levels. A significant negative correlation was found between the otoacoustic emission levels and the concentration of the styrene urinary metabolites. Otoacoustic emissions, and particularly distortion products, were able to discriminate the exposed workers from the controls, providing also a rough estimate of the slope of the dose-response relation between otoacoustic levels and styrene exposure.
    The Journal of the Acoustical Society of America 11/2013; 134(5):3739-48. DOI:10.1121/1.4824618 · 1.50 Impact Factor
Show more