TY - JOUR
T1 - Assessment of butadiene exposure in synthetic rubber manufacturing workers in Texas using frequencies of hprt mutant lymphocytes as a biomarker
AU - Ward, Jonathan B.
AU - Abdel-Rahman, Sherif Z.
AU - Henderson, Rogene F.
AU - Stock, Thomas H.
AU - Morandi, Maria
AU - Rosenblatt, Judah I.
AU - Ammenheuser, Marinel M.
N1 - Funding Information:
This project was supported by a grant from the National Institute of Environmental Health Sciences (R01ES06015). Additional support was provided by the NIEHS Toxicology Center at UTMB (P30ES06676), and the General Clinical Research Center at UTMB (M01RR00073). We thank the Workplace Toxics Foundation, and the members of the Paper, Allied-Industrial, Chemical and Energy Workers International Union Local 2-228, both of Port Neches, TX, for their support and participation in the study. We also thank Gene Groff for his assistance and advice, Jene Barker for her technical assistance, and Tonya Groh for preparation of the manuscript.
PY - 2001/6/1
Y1 - 2001/6/1
N2 - 1,3-Butadiene (BD), which is used to manufacture synthetic rubber, is a mutagen and carcinogen. Because past occupational exposures have been associated with an increased risk of leukemia, there has been a dramatic reduction in workplace exposure standards. The health benefits of these reduced levels of occupational exposure to BD will be difficult to evaluate using relatively insensitive traditional epidemiological studies; however, biomarkers can be used to determine whether there are genotoxic effects associated with recent exposures to BD. In past studies of BD-exposed workers in Southeast Texas, we observed an increase in the frequency of lymphocytes with mutations in a reporter gene, hprt. Frequencies of hprt mutant cells correlated with air levels of BD and with the concentration of a BD metabolite in urine. Average exposures to 1-3 parts per million (p.p.m.) of BD were associated with a threefold increase in hprt variant (mutant) frequencies (Vfs). We now report results from a follow-up study of workers in a synthetic rubber plant in Southeast Texas. Thirty-seven workers were evaluated on three occasions over a 2-week period for exposure to BD by the use of personal organic vapor monitors and by determining the concentration of a BD metabolite in urine. The frequency of hprt mutants was determined, by autoradiography, with lymphocyte samples collected 2 weeks after the final exposure measurement. Based on their work locations, the study participants were assigned to high-exposure (N = 22) or low-exposure (N = 15) groups. The BD exposure, ±standard error, of the workers in the high-exposure group (1.65 ± 0.52 p.p.m.) was significantly greater than the low-exposure group (0.07 ± 0.03 p.p.m.; P < 0.01). The frequency of hprt mutant lymphocytes was also significantly different in the two groups (high, 10.67 ± 1.5 × 10-6; low, 3.54 ± 0.6 × 10-6; P < 0.001). The concentration of the urine metabolite was greater in the high-exposure group, but the difference was not significant. The correlation coefficient between hprt Vf and BD exposure levels was r = 0.44 (CI95, 0.11-0.69; P = 0.011). This study reproduced the findings from a previous study at this plant. Although studies of butadiene-exposed workers in other countries have not detected an effect of exposure on frequencies of hprt mutant lymphocytes, we have repeatedly observed this result in our studies in Texas.
AB - 1,3-Butadiene (BD), which is used to manufacture synthetic rubber, is a mutagen and carcinogen. Because past occupational exposures have been associated with an increased risk of leukemia, there has been a dramatic reduction in workplace exposure standards. The health benefits of these reduced levels of occupational exposure to BD will be difficult to evaluate using relatively insensitive traditional epidemiological studies; however, biomarkers can be used to determine whether there are genotoxic effects associated with recent exposures to BD. In past studies of BD-exposed workers in Southeast Texas, we observed an increase in the frequency of lymphocytes with mutations in a reporter gene, hprt. Frequencies of hprt mutant cells correlated with air levels of BD and with the concentration of a BD metabolite in urine. Average exposures to 1-3 parts per million (p.p.m.) of BD were associated with a threefold increase in hprt variant (mutant) frequencies (Vfs). We now report results from a follow-up study of workers in a synthetic rubber plant in Southeast Texas. Thirty-seven workers were evaluated on three occasions over a 2-week period for exposure to BD by the use of personal organic vapor monitors and by determining the concentration of a BD metabolite in urine. The frequency of hprt mutants was determined, by autoradiography, with lymphocyte samples collected 2 weeks after the final exposure measurement. Based on their work locations, the study participants were assigned to high-exposure (N = 22) or low-exposure (N = 15) groups. The BD exposure, ±standard error, of the workers in the high-exposure group (1.65 ± 0.52 p.p.m.) was significantly greater than the low-exposure group (0.07 ± 0.03 p.p.m.; P < 0.01). The frequency of hprt mutant lymphocytes was also significantly different in the two groups (high, 10.67 ± 1.5 × 10-6; low, 3.54 ± 0.6 × 10-6; P < 0.001). The concentration of the urine metabolite was greater in the high-exposure group, but the difference was not significant. The correlation coefficient between hprt Vf and BD exposure levels was r = 0.44 (CI95, 0.11-0.69; P = 0.011). This study reproduced the findings from a previous study at this plant. Although studies of butadiene-exposed workers in other countries have not detected an effect of exposure on frequencies of hprt mutant lymphocytes, we have repeatedly observed this result in our studies in Texas.
KW - Biomarker
KW - Butadiene
KW - Human study
KW - Lymphocytes
KW - hprt mutation
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U2 - 10.1016/S0009-2797(01)00183-1
DO - 10.1016/S0009-2797(01)00183-1
M3 - Article
C2 - 11397407
AN - SCOPUS:17044453422
SN - 0009-2797
VL - 135-136
SP - 465
EP - 483
JO - Chemico-Biological Interactions
JF - Chemico-Biological Interactions
ER -