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/m3 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/m3 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.

Review on Potential Risk Factors in Wafer Fabrication Process of Semiconductor Industry / 대한산업의학회지

OBJECTIVES: To associate work in the semiconductor industry, including silicon wafer fabrication, with cancer risks or mortality and other adverse health effects, the operation of wafer fabrication should initially be understood. A detailed study on the fabrication operation allows retrospective exposure to be assessed and wafer fabrication workers to be classified into similar exposure groups. Therefore, the objective of this study was to comprehensively review silicon wafer fabrication operations and related hazardous materials and agents. METHODS: The literatures related to semiconductor industry processes were reviewed from an occupational health viewpoint based on wafer manufacturing, wafer fabrication and packaging. The focus was especially related to the hazardous materials used in wafer fabrication industries. RESULTS: During the fabrication of silicon wafers, many toxic chemicals, a strong electric field and hazardous equipment are used. The process allows the integration of a three-dimensional array of electric circuits onto a silicon wafer substrate. Wafers are sliced from single crystal silicon and subject to a series of steps during the fabrication process, which alternatively adds and then selectively removes materials in layers from the surface of the wafer to create different parts of the completed integrated circuit. There are four major steps in this process; patterning, junction formation, thin film and metallization. CONCLUSIONS: In order to associate exposure to the hazard agents generated during wafer fabrication operations with adverse health effects the details of the operation should be completely studied, which will be helpful in both exposure assessments and epidemiological studies.

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.

Annual Changes of Lung Function in Retired Workers Exposed to Inorganic Dusts / 결핵및호흡기질환

BACKGROUND: The aim of this study was to investigate annual changes in pulmonary function in workers who were exposed to inorganic dust. METHODS: The subjects were 2,922 male patients who had been diagnosed with pneumoconiosis more than twice during 6 years from 2005 to 2010. RESULTS: Of the 2,922 cases, forced vital capacity (FVC) decreased by 54 mL in 1 year. In contrast, the annual change of forced expiratory volume in one second (FEV1) decreased by 56 mL. CONCLUSION: This is the first study that has investigated the annual change in pulmonary function in workers exposed to inorganic dust. The results will help estimate the pulmonary condition of patients who are unable to perform a pulmonary function test due to age or a disorder.

Comparison of Sevoflurane with Enflurane Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: Sevoflurane has a low blood-gas partition coefficient, resulting in rapid induction and recovery. We compared the effects of sevoflurane with those of enflurane anesthesia on parturients and neonates during and after elective cesarean section. METHODS: Ninety-six parturients were divided into two groups: E (enflurane, n = 47) and S (sevoflurane, n = 49). After endotracheal intubation with intravenous administration of thiopental 4 mg/kg and succinylcholine 1.5 mg/kg, anesthesia was maintained with 50% nitrous oxide in oxygen and enflurane 1 vol% or sevoflurane 1 vol%. Maternal hemodynamic parameters, blood loss, and recovery were monitored. Neonatal outcome was evaluated by Apgar scores, umblical artery blood gas analysis and acid-base status. RESULTS: Recovery times were faster with sevoflurane anesthesia (P < 0.05). All patients in two groups developed transient hypertension and tachycardia after intubation, which returned to baseline in approximately 5 minutes. Maternal blood loss did not differ significantly between the two groups, and one patient in S group developed postoperative recall. Neonatal outcome was equally good in the two groups. CONCLUSIONS: Parturients anesthetized with sevoflurane for cesarean section recovered more rapidly compared with enflurane without any differences in hemodynamic parameters and neonatal outcome.

Respiratory Difficulty at a Postanesthesia Care Unit after Total Thyroidectomy: A case report / 대한마취과학회지

We had a case of respiratory difficulty following total thyroidectomy due to bilateral vocal cord palsy. The patient was a 49-year-old female undergoing total thyroidectomy for papillary carcinoma of the thyroid. Anesthesia was performed uneventfully. Spontaneous respiration resumed after reversal of the neuromuscular blockade. However, after arriving at the postanesthesia care unit, she developed hypertension, anxiety, tachypnea, and inspiratory stridor during deep inspiration. Because the patient maintained adequate oxygen saturation, we confirmed bilateral vocal cord palsy by fiberoptic laryngoscopy. During the operation, the surgeon experienced difficulty dissecting the bilateral recurrent laryngeal nerves from the surrounded tumor. So we consider that direct nerve injury was responsible for the bilateral vocal cord palsy. Movement of the right vocal cord recovered a week later.

Respiratory Difficulty at a Postanesthesia Care Unit after Total Thyroidectomy: A case report / 대한마취과학회지

We had a case of respiratory difficulty following total thyroidectomy due to bilateral vocal cord palsy. The patient was a 49-year-old female undergoing total thyroidectomy for papillary carcinoma of the thyroid. Anesthesia was performed uneventfully. Spontaneous respiration resumed after reversal of the neuromuscular blockade. However, after arriving at the postanesthesia care unit, she developed hypertension, anxiety, tachypnea, and inspiratory stridor during deep inspiration. Because the patient maintained adequate oxygen saturation, we confirmed bilateral vocal cord palsy by fiberoptic laryngoscopy. During the operation, the surgeon experienced difficulty dissecting the bilateral recurrent laryngeal nerves from the surrounded tumor. So we consider that direct nerve injury was responsible for the bilateral vocal cord palsy. Movement of the right vocal cord recovered a week later.