Occupational exposure to styrene in the fibreglass reinforced plastic industry: comparison between two different manufacturing processes.

BACKGROUND: 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. OBJECTIVES: 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). METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Development and validation of method for analysis of some ototoxic solvents in saliva matrix by headspace gas chromatography/mass spectrometry.

The aim of this study was to develop an analytical method to monitor the saliva matrix for ototoxic solvents absorption: the method is based on headspace gas chromatography/mass spectrometry and represents an alternative biological monitoring for investigating low exposure to hazardous ototoxic solvents. Simultaneous determination of toluene, ethylbenzene, xylenes and styrene has been carried out and the method has been optimized for both instrumental parameters and samples treatment. Chromatographic conditions have been set in order to obtain a good separation of xylene isomers due to the interest in p-xylene as ototoxic one. Method validation has been performed on standards spiked in blank saliva by using two internal standards (2-fluorotoluene and deuterated styrene-d(8)). This method showed the possibility to detect the target compounds with a linear dynamic range of at least a 2 orders of magnitude characterized by a linear determination coefficient (r(2)) greater than 0.999. The limit of detection (LOD) ranged between 0.19 ng/mL (styrene) and 0.54 ng/mL (m-xylene) and the lower limit of quantification (LLOQ) ranged between 0.64 ng/mL (styrene) and 1.8 ng/mL (m-xylene). The method achieved good accuracy (from 99 to 105%) and precision for both intra- and inter-assay (relative standard deviation ranging from 1.7 to 13.8%) for all six compounds concerned. The repeatability was improved by adding sodium sulphate to the matrix. Saliva samples resulted stable for at least 7 days after collection, if stored in headspace vials, at the temperature of 4 degrees C. An evaluation of the main sources of uncertainty of the method is also included: expanded uncertainties ranges between 10 and 16% for all of the target compounds. In summary, the headspace gas chromatography/mass spectrometry method is a highly sensitive, versatile and flexible technique for the biological monitoring of exposure to ototoxic solvents by saliva analysis.