博士 / 國立陽明大學 / 公共衛生研究所 / 95 / The purpose of this study is to assess the protective effectiveness for workers wearing respirators, chemical protective suits and gloves in the field. Second, we determine the contribution of dermal absorption on the total exposure dose and evaluate the relevance of inhalation and dermal exposure to solvents, and urinary metabolites. The emphasis was on the spatial distribution of the solvents across the body of dermal exposure.
Spray painters working at a ship coating plant were recruited for this study. The study included three sampling periods. First, in December 2003, eighteen spray painters participated in the study for 3 days. Air samples outside and inside the protective mask were collected using passive samplers, respectively. Urine specimens were collected before and after the work shift. Second, in March 2005, fifteen spray painters participated in the study for two weeks. Subjects worked without protective suits and gloves for the first week and with suits and gloves the following week. All workers wore respirators during spray painting throughout the two-week period of the study. Sampling was conducted on 4 consecutive working days each week. Air sampling was collected using passive samplers. Urine specimens were collected before and after the work shift. Third, in August 2005, fifteen spray painters participated in the study for 3 days. Air samples outside and inside the mask were collected using passive samplers, respectively. Samples for measuring dermal exposure to solvents were collected using activated charcoal patches. Urine specimens were collected before and after the work shift. Air and dermal samples were quantified by gas chromatograph with a flame ionization detector (GC/FID). Urinary mandelic acid (MA) and methyl hippuric acid (MHA) were determined by high performance liquid chromato- graphy with a UV detector (HPLC/UV).
Air samples showed that workers were primarily exposed to xylene and ethyl benzene. The median workplace protection factors of respirators for xylene and ethyl benzene were 25.0 and 17.4, respectively. On average, wearing respirators could reduce xylene inhalation by 96% and ethyl benzene inhalation by 94% for workers. The contribution of dermal absorption to the total exposure dose of xylene was estimated to be 63.7±4.27%.
The average ethyl benzene and xylene mass among body regions inside block units of assembled ships were 305.1±63.9 mg and 165.6±34.1 mg, which were 5.8 and 5.1 times higher than those collected outside the blocks, respectively. In both measurements, the highest exposure mass were found on the upper legs and the lowest exposure mass were found on the back. The sampling time of dermal exposure outside and inside blocks were 78.2±10.5 and 83.6±13.3 min. No statistical difference in sampling time of dermal exposure outside and inside blocks was found (p=0.751). Multiple regression analyses revealed a significant relation between dermal exposure to xylene and urinary methylhippuric acid (MHA) levels adjusting for xylene levels in air samples (R2 = 0.491, p < 0.05).
In addition, urinary mandelic acid (MA) and MHA levels were divided by the personal exposure concentrations of ethyl benzene and xylene, respectively. The mean±SE corrected MA and MHA concentrations in the first week were 1.76±0.35 and 2.66 ±0.68 (mg/g creatinine)/(mg/m3), whereas they were 0.50±0.12 and 1.07±0.18 (mg/g creatinine)/(mg/m3) in the second week, respectively. Both MA and MHA concentrations in the second week the spray painters wore protective suits and gloves were smaller than those in the first week, respectively (p < 0.001, p = 0.011). The mean decrease in MA and MHA concentrations were 69 % and 49 %, respectively.
The present study showed inhalation of solvent vapors in shipyard spray painters decreased as a result of wearing respirators and dermal absorption of solvents became the main contributor to the total body burden. Additionally, dermal exposure mass to xylene significantly increased the urinary levels of MHA, suggesting that dermal exposure to solvents was an important route among spray painters. The study also successfully evaluated the field protection effectiveness of chemical protective suits and gloves by using biomarkers such as urinary MA and MHA. Moreover, wearing protective suits and gloves will effectively reduce the risk of absorbing organic solvents through the skin. Spray painters should wear chemical protective suits and gloves as a critical protective measure.
| Identifer | oai:union.ndltd.org:TW/095YM005058012 |
| Date | January 2007 |
| Creators | Fu-Kuei Chang, 張富貴 |
| Contributors | I-Fang Mao, Mei-Lien Chen, 毛義方, 陳美蓮 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 111 |
Page generated in 0.0309 seconds