Study On Setting Occupational Exposure Limit Of1-Bromopropane

1-Bromopropane (1-BP) is widely used in producing spray adhesive, degreasing and precision cleaning as well as an intermediate in the synthesis of pharmaceuticals, pesticides, flavors and fragrances. As chlorofluorocarbons and other ozone depletion chemicals have been banned in many countries.1-BP was introduced as an alternative and increasingly used around the world.In China, there are many plants that produce or use1-bromopropane, especially in Shandong and Jiangsu province. Even through the total number of exposed workers is still not clear; it is increasing gradually for sure. Studies showed that1-BP may have several kinds of toxicity such as neurotoxicity, reproductive and developmental toxicity. Besides,1-BP was reported to cause cancer in experimental animals. Also, there are cases reporting that peripheral and central nervous systems, as well as hematological system and liver function of1-BP exposed workers were injured. However, there is still a blank area in occupational exposure limit and standardized analytical method for airborne1-BP detection in China so far. Exposure assessment of1-BP is now a crucial need as a part of the job of understanding the exposure level and adverse health effect to finally provide evidences for the setting of occupational exposure limit.To detect airborne1-BP at workplace, gas chromatography with flame ionization detector (GC-FID) was used. Temperature of SPB-1capillary column (30m*0.25mm*0.25μm) was increased gradually. Nitrogen was used as the carrier and sample was injected at a10:1split ratio.1-BP in air of workplace was collected with activated charcoal tube, dissolved by carbon disulfide and determined by GC-FID.1-BP was quantitatively determined using retention time and peak area. The analytical method was assessed according to Guide for establishing occupational health standards-determination methods of air chemicals. Results showed that1-BP can be well separated from the most common contamination2-BP. Linear regression analysis showed that1-BP can be analyzed in a range of2.50～500.00μg/ml, R2==0.9996. Detection limit was0.25μg/ml and the lowest detection concentration of1-brmopropane in air was0.08mg/m3by assuming that3L air were collected. Relative standard deviations of inter and intra-assay were less than10%. The mean recovery was between95%and105%. Desorption efficiency was more than90%. Decreasing rate of the fifth day under room temperature was less than10%and penetration capacity was more than1.75mg. We can come to the conclusion that the method which is established in our study is applicable to determine1-BP in workplace air.To investigate the relationship between health condition and occupational1-BP exposure, an occupational health study was conducted in a1-BP producing plant. The operation history and technical process of a1-BP manufacturing plant were investigated. The health examination data of workers were collected. Fixed site and personal sampling (both active and passive) methods were used to determine the environmental and personal1-BP exposure, respectively. Relationship between exposure and health condition of these workers was analyzed.1-BP could be detected at all of the selected worksites with a maximum of153.08mg/m3at the site which is close to receiving pot. The highest geometric median concentration was43.62mg/m3in the distilling room while the lowest was1.95mg/m3outsides production line. There were no significant differences between active and passive sampling. The health examination data, including neurological examination data, showed that no obvious health effect was caused by1-bromopropane exposure in our study. Workers’ health was not found to be affected by1-bromopropane under the current exposure level.Studies showed that benchmark dose (BMD) and the lower-bound confidence limit (BMDL) were36.77mg/m3and21.73mg/m3if tibia nerve distal latency (DL) was used as health effect, respectively. When creatine kinase (CK) was taking into account, BMD and BMDL were88.28mg/m3and44.52mg/m3, respectively. When thyroid stimulating hormone (TSH)was used as health effect, BMD and BMDL were47.23mg/m3and31.54mg/m3, respectively. Considering the exposure limits of some other countries, we suggest21mg/m3as occupation exposure of TWA-8h by taking peripheral nervous system as the critical effect.