Characterization of Total and Size-Fractionated Manganese Exposure by Work Area in a Shipbuilding Yard.

BACKGROUND: Shipbuilding involves intensive welding activities, and welders are exposed to a variety of metal fumes, including manganese, that may be associated with neurological impairments. This study aimed to characterize total and size-fractionated manganese exposure resulting from welding operations in shipbuilding work areas. METHODS: In this study, we characterized manganese-containing particulates with an emphasis on total mass (n = 86, closed-face 37-mm cassette samplers) and particle size-selective mass concentrations (n = 86, 8-stage cascade impactor samplers), particle size distributions, and a comparison of exposure levels determined using personal cassette and impactor samplers. RESULTS: Our results suggest that 67.4% of all samples were above the current American Conference of Governmental Industrial Hygienists manganese threshold limit value of 100 µg/m(3) as inhalable mass. Furthermore, most of the particles containing manganese in the welding process were of the size of respirable particulates, and 90.7% of all samples exceeded the American Conference of Governmental Industrial Hygienists threshold limit value of 20 µg/m(3) for respirable manganese. CONCLUSION: The concentrations measured with the two sampler types (cassette: total mass; impactor: inhalable mass) were significantly correlated (r = 0.964, p < 0.001), but the total concentration obtained using cassette samplers was lower than the inhalable concentration of impactor samplers.

Determination of Phthalate Metabolites in Human Serum and Urine as Biomarkers for Phthalate Exposure Using Column-Switching LC-MS/MS.

OBJECTIVES: Although phthalates like dibutyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) are commonly used as plasticizers and their metabolites are especially suspected of reproductive toxicity, little is known about occupational exposure to those phthalates. The aim of this study was to assess the utility of measuring the metabolite concentrations of DBP and DEHP in serum and urine samples as an indicator of occupational exposure to those phthalates. METHODS: Phthalate metabolites were analyzed by using column-switching high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). RESULTS: We detected phthalate metabolites in serum and urine matrices at approximately 10-fold lower than the limit of detection of those metabolites in the same matrix by LC-MS/MS without column switching, which was sufficient to evaluate concentrations of phthalate metabolites for industrial workers and the general population. CONCLUSION: The accuracy and precision of the analytical method indicate that urinary metabolite determination can be a more acceptable biomarker for studying phthalate exposure and adverse health outcomes.

Extensive changes to occupational exposure limits in Korea.

Occupational exposure limits (OELs) are used as an important tool to protect workers from adverse chemical exposures and its detrimental effects on their health. The Ministry of Labor (MOL) can establish and publish OELs based on the Industrial Safety and Health Act in Korea. The first set of OELs was announced by the MOL in 1986. At that time, it was identical to the Threshold Limit Values of the American Conference of Governmental Industrial Hygienists. Until 2006, none the first OELs except for those of three chemicals (asbestos, benzene, and 2-bromopropane) were updated during the last twenty years. The Hazardous Agents Review Committee established under the MOL selected 126 chemicals from 698 chemicals covered by OELs using several criteria. From 2005 to 2006, the MOL provided research funds for academic institutions and toxicological laboratories to gather the evidence documenting the need to revise the outdated OELs. Finally, the MOL notified the revised OELs for 126 chemicals from 2007 to 2008. The revised OELs of 58 substances from among these chemicals were lowered to equal or less than half the value of the original OELs. This is the most substantial change in the history of OEL revisions in Korea.

Laboratory and field validation of the GC-NPD method for the measurement of formaldehyde in the workplace.

Formaldehyde is classified as a suspected or probable human carcinogen by several organizations. Since conventional sampling and analytical methods for airborne formaldehyde show relatively poor sensitivity, an improved method is needed. The aim of this study was to develop a new analytical method for measuring the airborne formaldehyde concentrations in workplaces and to evaluate the performance of the method through laboratory and field tests. The method employs a sampling tube containing silica gel coated with 2, 4-dinitrophenylhydrazine (2,4-DNPH), which produces 2,4-DNPH-formaldehyde derivative with formaldehyde. Then the 2,4-DNPH-formaldehyde derivative is analyzed using gas chromatography (GC) equipped with a nitrogen-phosphorus detector (GC-NPD). In laboratory tests, the new method, referred to as the GC-NPD method, was as sensitive as the National Institute for Occupational Safety and Health (NIOSH) analytical method, which uses high-performance liquid chromatography equipped with ultraviolet detector. The total analytical precision and 95% confidence limit of the estimated total standard error for the GC-NPD method were 0.009 and +/- 12.0%, respectively, which satisfied the OSHA sampling and analytical criteria. In field tests, the overall uncertainty of the GC-NPD method was 11.2%, which satisfied the NIOSH criteria for sampling and analytical methods. The GC-NPD method with a 2,4-DNPH coated adsorbent sampler for the determination of airborne formaldehyde concentration showed good performance with acceptable accuracy and precision.