Determination of eight volatile halogenated hydrocarbons in drinking water by headspace thermal desorption⁃gas mass spectrometry / 上海预防医学

ObjectiveTo establish a method for the determination of 8 volatile halogenated hydrocarbons in drinking water， including vinyl chloride， trichloroethylene， tetrachloroethylene， tetrachloromethane， chloroform， dichlorobromomethane， dichlorodibromomethane， and tribromomethane by headspace thermal desorption-gas mass spectrometry. MethodsThe water sample was kept in the headspace bottle at 60 ℃ for 40 min， and the volatile matter was transferred to the cold trap，subjected to thermal desorption， then analyzed by gas chromatography-mass spectrometry. ResultsThe linear ranges were 0.2‒20.0 μg·L-1 for vinyl chloride， 0.1‒20.0 μg·L-1 for chloroform， 0.02‒20.00 μg·L-1 for tetrachloromethane， 0.2‒20.0 μg·L-1 for trichloroethylene， 0.3‒20.0 μg·L-1 for dichlorobromomethane， 0.1‒20.0 μg·L-1 for tetrachloroethylene， 0.4‒20.0 μg·L-1 for dichlorodibromomethane， and 1.0‒20.0 μg·L-1 for tribromomethane. All the correlation coefficients were more than 0.997. The respective quantitative limits were 0.162， 0.073， 0.016， 0.184， 0.270， 0.071， 0.356 and 0.813 μg·L-1， and the respective recoveries were 98.0%‒101.0%， 102.0%‒110.0%， 99.2%‒101.0%， 95.5%‒96.2%， 96.0%‒102.0%， 100.0%‒102.0%， 99.0%‒105.0%， and 94.0%‒103.0%. ConclusionThe method is simple， sensitive， rapid， accurate and reliable， so it is applicable for the determination of 8 kinds of volatile halogenated hydrocarbons in drinking water.

Raynaud's phenomenon in the occupational context

SUMMARY OBJECTIVE To review articles that evaluated the prevalence of Raynaud's phenomenon of occupational origin. METHODS The search for articles was carried out in the Medline (via PubMed), Embase, Web of Science, Scientific Electronic Library Online (SciELO), and Latin America and Caribbean Health Sciences Literature (Lilacs) databases. RESULTS 64 articles were obtained from the electronic search; 18 articles met the eligibility criteria. All studies discussed the exposure to vibrations in the upper limbs. In 6 of them, the thermal issue was directly or indirectly addressed. No studies have addressed exposure to vinyl chloride. CONCLUSIO In general, a higher prevalence of Raynaud's phenomenon was found among vibratory tool operators compared to non-exposed workers, with an increase in the number of cases the higher the level of vibration and the time of exposure. Cold is a triggering and aggravating factor of the Raynaud phenomenon and seems to play an important role in the emergence of vascular manifestations of the hand-arm vibration syndrome.

RESUMO OBJETIVO Realizar um estudo de revisão dos artigos que avaliaram a prevalência do fenômeno de Raynaud de origem ocupacional. MÉTODOS A busca pelos artigos foi realizada nas bases de dados Medline (via PubMed), Embase, Web of Science, Scientific Eletronic Library Online (SciELO) e Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs). RESULTADOS Sessenta e quatro artigos foram obtidos a partir da busca eletrônica, dos quais 18 cumpriram os critérios de elegibilidade. Todos os estudos discutiram sobre a exposição a vibrações localizadas em membros superiores. Em seis deles, a questão térmica foi direta ou indiretamente abordada. Nenhum estudo abordou a exposição ao cloreto de vinila. CONCLUSÃO De maneira geral, constatou-se maior prevalência do fenômeno de Raynaud entre operadores de ferramentas vibratórias em comparação aos não expostos, com aumento do número de casos quanto maior o nível de vibração e tempo de exposição. O frio é fator desencadeante e agravante do fenômeno de Raynaud e parece exercer papel importante para o surgimento das manifestações vasculares da síndrome de vibração de mãos e braços.

Effect of vinyl chloride on liver function and serum sex hormones in male workers / 中国职业医学

OBJECTIVE: To explore the effect of vinyl chloride on the blood sex hormones and liver function of male workers. METHODS: A total of 129 male vinyl chloride workers(exposure group) and 128 male office workers who were not exposed to occupational hazards(control group) were selected as study subjects by judgment sampling method. The time weighted average concentration(C_(TWA)) of vinyl chloride in the workplace air was measured. The level of urine thiodiglycolic acid(TDGA), blood routine, electrocardiogram and liver B-ultrasound were performed on the subjects. The serum levels of liver function and sex hormones were measured. RESULTS: The median of C_(TWA) of vinyl chloride in the workplace was 0.90 mg/m~3, and the geometric mean was 1.40 mg/m~3. The level of urine TDGA in the exposed group was higher than that of the control group(median: 0.68 vs 0.02 mg/g Cr, P<0.01). The abnormal rate of hemoglobin level, erythrocyte count, leukocyte count, hematocrit, mean platelet volume, aspartate transaminase, total bilirubin, indirect bilirubin and liver B-ultrasound increased in the exposure group than that of the control group(P<0.05). The levels of serum prolactin, leuteinizing hormone(LH), follicle-stimulating hormone and estradiol in the exposure group increased, the abnormal rates of prolactin, LH and estradiol increased, and the level of testosterone decreased compared with the control group(P<0.05). The levels of prolactin in the low-, medium-and high-TDGA subgroups in the exposure group increased(P<0.05), and the abnormal rates increased compared with the control group(P<0.017). CONCLUSION: Vinyl chloride can cause liver function damage in male workers and have reproductive toxicity. Prolactin can be used as a biomarker of reproductive toxicity of vinyl chloride.

Carcinogens that induce the A:T > T:A nucleotide substitutions in the genome / 医学前沿

Recently, Ng et al. reported that the A:T > T:A substitutions, proposed to be a signature of aristolochic acid (AA) exposure, were detected in 76/98 (78%) of patients with hepatocellular carcinoma (HCC) from the Taiwan Province of China, and 47% to 1.7% of HCCs from the Chinese mainland and other countries harbored the nucleotide changes. However, other carcinogens, e.g., tobacco carcinogens 4-aminobiphenyl and 1,3-butadiene, air toxic vinyl chloride and its reactive metabolites chloroethylene oxide, melphalan and chlorambucil, also cause this signature in the genome. Since tobacco smoke is a worldwide public health threat and vinyl chloride distributes globally and is an air pollutant in Taiwan Province, the estimation of the patients' exposure history is the key to determine the "culprit" of the A:T > T:A mutations. Apparently, without estimation of the patients' exposure history, the conclusion of Ng et al. is unpersuasive and misleading.

Simultaneous Determination of Vinyl Chloride and Vinylidene Chloride in Drug Packaging Materials Con-taining Polyvinyl Chloride/Polyvinylidene Chloride by HS-GC / 中国药师

Objective:To develop a method for the simultaneous determination of vinyl chloride and vinylidenechloride in drug packaging materials containing polyvinyl chloride /polyvinylidene chloride by HS-GC.Methods: A Stabilwax (30.0 m ×0.25 mm, 0.25 μm) capillary column and an FID detector were adopted .The headspace equivalent temperature was 80℃for 30 min and the col-umn temperature was 40℃.The inlet temperature was 190℃and the detector temperature was 210℃.N2 was used as the carrier gas . The flow rate was 1.0 ml · min-1 .Results: Vinyl chloride had a good linear relationship within the range of 0.5-2.5 μg ( r =0.996 7), and the average recovery was 90.4%(RSD=0.9%, n=9).Vinylidenechloride had a good linear relationship within the range of 1.0-5.0 μg (r=0.999 0), and the average recovery was 90.0%(RSD=0.6%, n=9).Conclusion: The method is fast and accurate in the simultaneous determination of vinyl chloride and vinylidenechloride in drug packaging materials containing polyvinyl chloride/polyvinylidene chloride .

The effects of vinyl chloride monomer on the expression of mir-122 in the liver tissue and serum of male rat / 中国职业医学

OBJECTIVE: To explore the effects of vinyl chloride monomer( VCM) on the expression of mir-122 in the liver tissue and serum of rat. METHODS: Specific pathogen free adult male SD rats were randomly divided into 4 groups with 24 rats in each group: the control group,the low-,medium- and high-dose groups. The 4 groups were intraperitoneally injected with VCM exposure levels at 0,5,25 and 125 mg / kg body weight 3 times per week,respectively. Eight rats per group were randomly selected and sacrificed after 6,8 and 12 weeks. Small RNA( < 200 nt) in the liver tissue and total RNA in the serum were isolated and purified. Real-time fluorescent quantitative polymease chain reaction technique was used to detect their expressions of mir-122. RESULTS: Compared with the control group and the low-dose group at the same time points,the relative expressions of mir-122 in the liver tissue of rats in the medium- and high-dose groups were significantly increased after exposed to VCM for 6 weeks( P < 0. 05),and then were significantly decreased after exposed to VCM for 12 weeks( P < 0. 05). The relative expressions of mir-122 in the liver tissue of rats in the medium- and highdose groups were decreased with VCM exposure time( P < 0. 05). Compared with the control group at the same time points,the relative expressions of mir-122 in serum of rats in the three dose groups were significantly increased after being exposed to VCM for 8 weeks( P < 0. 05),and then were significantly decreased after being exposed to VCM for 12 weeks(P < 0. 05). Among the three dose groups,the relative expressions of mir-122 in serum of rats after 12-week exposure were lower than those after 6-week and 8-week exposure in the same group respectively( P < 0. 05). CONCLUSION:s The VCM exposure significantly changes the expression of mir-122 in the liver tissue and serum of rat,which suggested that mir-122 may be one of the effect biomarkers for VCM exposure.

Urinary Excretion of Thiodiglycolic Acid According to Sampling Time in Workers Exposed to Vinyl Chloride Monomer / 대한산업의학회지

OBJECTIVES: The study was performed to investigate the changes of urinary thiodiglycolic acid (TDGA) concentration in workers exposed to vinyl chloride monomer (VCM) according to the time of sampling urine. METHODS: The personal exposure to airborne VCM was assessed and urinary TDGA concentration was sampled in 31 workers employed in a VCM and polyvinyl chloride (PVC) manufacturing factory. Urinary TDGA was sampled three times: before the start of the shift after 3 days off (TDGA1), after the end of the first-day shift (TDGA2) and before starting the following day shift after completing the oneday shift (TDGA3). Urinary TDGA in 30 workers who had not been exposed to airborne VCM was sampled after the end of the shift. A gas chromatography/pulsed flame photometric detector (GC/PFPD) was utilized to analyze TDGA concentration in urine after the urine was methylated with trimethylsilyldiazomethane(2.0M in diethyl ether). RESULTS: The creatinine level was 0.179+/-0.271 mg/g in the control workers and 0.218+/-0.443 mg/g in the workers before the start of the shift after 3 days off (TDGA1), showing no significant difference (p=0.7035). Urine samples were compared according to sampling time in order to investigate the change of urinary TDGA concentration in the case of continuous exposure to airborne VCM. In VCM-exposed workers, urinary creatinine concentration was 0.434+/-0.623 mg/g in TDGA2 and 0.767+/-1.056 mg/g in TDGA3, which indicated a gradual but significant increase (p=0.024). In terms of the statistical correlation between airborne VCM and urinary TDGA to evaluate exposure dose per day, of the three urinary TDGA concentrations, TDGA3 showed the highest degree of regression (R(2)=0.4215) with 8h-TWA airborne VCM concentration. CONCLUSION: Based on this result, the excretion half-life of urinary TDGA was assumed to be less than 3 days, because the concentration of urinary TDGA at 3 days after exposure to airborne VCM was decreased to the level of urinary TDGA concentration in the control workers. The concentration of urinary TDGA increased in the case of continuous shift, due to the accumulation of residual metabolites of TDGA. It was considered that TDGA3 can be applied as a useful biological index to evaluate the exposure dose of airborne VCM during one day because TDGA3 showed the highest correlation with the exposure dose of airborne VCM in the previous shift day.

Evaluation method for vinyl chloride exposed workers

BACKGROUND: This study was conducted to evaluate vinly chloride exposure in vinyl chloride and poly vinyl chloride manufacturing factories. The object of this study was compare two different type of air sampling method that of, NIOSH and OSHA recommended and Investigate quantitative correlation between level of vinyl chloride exposure and urinary thiodiglycolic acid excretion. METHODS: Air sampling was conducted by two method and sampling mediums were located at workers breathing zone in the same location. Sampling mediums were changed in 60 minute interval and sampling pumps were recalibrated at the same time. Urine was collected before and end of shift were stored frozen and determined by GC/FID analysis. RESULTS: In NIOSH method, time weighted average was 3.562 +/- 2.898 ppm and OSHA method time weighted average was 4.051 +/- 3.700 ppm. Concentration of urinary TdGA in before shift was 0.527 +/- 0.828 g/g creatinine and end of shift was 4.190 +/- 7.665 mg/g creatinine. Difference of urinary TdGA between end of shift to before shift was 3.662 +/- 7.865 mg/g creatinine. In NIOSH method, correlation coefficient between 8hour-time weighted average (8hrs-TWA) and urinary concentration of TdGA was r=0.666. and last period vinyl chloride level (6th-TWA) and urinary TdGA concentration was r=0.972. In OSHA method, correlation coefficient between last period vinyl chloride level (6th-TWA) and urinary concentration of TdGA was r=0.976 and this was highest value. CONCLUSION: There was no statistically significant difference in NIOSH method and. OSHA method. A correlation were found between level of vinyl chloride exposure and urinary thiodiglycolic acid excretion. Also, vinyl chloride exposure had significantly effected on the urinary thiodiglycolic acid excretion.

The variation of thiodiglycolic acid concentration in urine with vinyl chloride exposure levels in rats / 대한산업의학회지

OBJECTIVES: It is the objective of this research to identify the variation of thiodiglycolic acid (TdGA) in urine with vinyl chloride monomer (VCM) exposure levels through methylation. METHODS: After rats were exposed to vinyl chloride monomer of 4 levels, 0 mg/m3, 50 mg /m3, 150 mg/m3, 500 mg/m3, respectively, of which urine was sampled in each sampling time of 0 hour, 2 hours, 4 hours, 8 hours, 16 hours, 24 hours, 36 hours, 48 hours. After urine had been methylated with diazomethane in the preliminary experiment and the peak of 146 m/z had been verified, the main experiment was done. RESULTS: In the variation of TdGA with sampling times, concentration of TdGA increased rapidly in 4 hours and then decreased after 8 hours. When the variation of urinary .TdGA concentration in urine according to exposure level of VCM was verified through Kruskal-Wallis statistical method at each sampling time, the significant increment with the exposure levels at 2 hours, 4 hours, 8 hours after exposure was clarified. CONCLUSION: TdGA concentration in urine with increment of VCM exposure level increased, especially significantly at 2 hours, 4 hours, 8 hours of sampling time.

Development of Methods to Estimate Exposure Levels to Vinyl Chloride Monomer and Multiphasic Screening Tests for Workers of Polyvinyl Chloride Manufacturing Factories / 대한산업의학회지

In order to develop questionnaire estimating vinyl chloride monomer(VCM) exposure levels, to reset selection criteria for detailed tests, to measure current VCM exposure levels, to evaluate the mutagenic effects of VCM exposures and to develop multiphasic screening method of PVC- or VCM-handling workers, VCM concentrations of work environments were measured and tentative self-administrative questionnaire, physical examination, sister chromatid exchange(SCE) test and some clinical chemical test were applied to 195 men who had been handling VCM or PVC(Exposed Group) and 37, in the same factories without exposure to VCM or in polyethylene- or polypropylene-related factories(Control Group). Mean VCM concentrations of work environments were 0.268+/-0.183 ppm under PVC synthesis processes, 0.160+/-0.200 ppm under VCM synthesis process, 0.076+/-0.111 ppm under PVC pipe producing processes, 0.090+/-0.108 ppm under PVC wall paper, sheet, or film producing processes, 0.071+/-0.051 ppm under PVC floor producing processes, 0.243+/-0.250 ppm under PVC sash producing processes, and 0.020+/-0.031 ppm under triming process. VCM levels of work environments under manual resin mixing processes (0.209+/-0.168 ppm)were higher than those of the others (0.209+/-0.168 ppm) (p-value0.05). SCE frequencies of the Exposed Group were significantly higher than those of Contorl Group(p-value<0.05) and those of test-abnormal persons were higher than those of test-normal persons. SCE frequencies linearly increased with not only current but also cumulative VCM exposure levels(p-value<0.05). These results suggest that adverse health effect may ensue from VCM exposure to as low as 1 ppm. But SCE frequencies had no statistically significant correlation with drinking amounts, smoking amoutns, or radiation dose equivalents. Questionnaire was revised by referring to these results and formula estimating cumulative VCM exposure levels based on occupational history in questionnaire were made. In addition, were presented methods evaluating work environments and multiphasic screening test for PVC workers.