A cross-sectional study about the effects of residential exposure to power transmission line on human nervous system symptoms and hematology / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the possible effects on nervous system and health condition under the exposure to electromagnetic field.</p><p><b>METHODS</b>Take the resident around the power transmission line as the objects and were divided into 3 groups by the distance from the power transmission line 20 m, 100 m and 500 m, respectively. Some living conditions and health conditions were recorded by face-to-face the questionnaire survey, and Hematological indices of each groups were examined including IgG, IgM, leukocyte formulae, erythrocyte, hemoglobin and platelet.</p><p><b>RESULTS</b>There was no significant difference in each group, according exposure of daily life, such as drinking and smoking (P > 0.05). Compared with the each distance groups, it was presented significant difference between the distance from the power transmission line and the incidence of headache or dizziness, insomnia and easy weary and so on (P < 0.05). In hematology aspect, with the horizontal distance from the power transmission line decreasing, PLT level of residents was reductive and the difference was statistically significant (P < 0.001), whereas leukocyte formulae, erythrocyte, hemoglobin, IgG and IgM had no significant difference among each group (P < 0.05).</p><p><b>CONCLUSION</b>Closely exposure to electromagnetic field may induce headache and so on and decrease the level of PLT.</p>

Study on the standard of health protection zone for petroleum processing industry / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish health protection zone standards for petroleum processing industry.</p><p><b>METHODS</b>The intensity of characteristic pollutants from fugitive emission were estimated by the inverse method of ground concentration through field survey and monitoring for representative petroleum processing industry, which was calculated health protection zone by using the model of atmospheric diffusion.</p><p><b>RESULTS</b>Characteristic pollutant of fugitive emission source from petroleum processing industry was confirmed as hydrogen sulfide. When local average wind speed in the past five years was less than 2, 2-4 m/s and more than 4 m/s respectively and meanwhile the scale of petroleum processing industry was less than 8 million tons, the recommended value of health protection zone were 900, 800, 700 m respectively. Besides, when the scale of petroleum processing industry was more than 8 million tons and in the same wind speed level, the recommended value of health protection zone were 1200, 1000, 900 m respectively.</p><p><b>CONCLUSIONS</b>Recommended value of health protection zone for petroleum processing industry was reasonable and feasible through revising and improving of the version of 1987's standard.</p>

Establishment of biological limit value of urinary S-phenylmercapturic acid for occupational exposure to benzene / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish the biological exposure limit values of urinary S-phenylmercapturic acid (SPMA) for assessing occupational exposure to benzene.</p><p><b>METHODS</b>Study participants were selected from 55 workers of benzene exposures below 32.5 mg/m(3). The concentration of personal exposure to benzene was measured by gas chromatography and sampled with personal sampler. The urine samples were collected at the end of work shift and individual internal exposure level was evaluated by determination of SPMA in urine by HPLC/MS method. Comparison of external and internal exposure was assessed by the relative internal exposure (RIE) index.</p><p><b>RESULTS</b>The benzene exposure level ranged from 0.71 to 32.17 mg/m(3) (geometric mean 6.98 mg/m(3), median 7.50 mg/m(3)). The urinary SPMA at the end of the work shift were significantly correlated with benzene exposure, (microg/g Cr) = -8.625 + 18.367X (mg/m(3)), r = 0.8035, (P < 0.01). According to the occupational exposure limit for benzene in China and calculation of regression equation, the expected value of urinary SPMA was 101.58 microg/g Cr. Mean level of biotransformation of per mg/m(3) benzene to urinary SPMA was 18.23 microg/g Cr and the metabolic efficiencies of benzene transformation to urinary SPMA decreased with benzene exposure increased.</p><p><b>CONCLUSION</b>Based on abroad documents and data, biological limit value for occupational exposure to benzene in China is recommended as follows: 100 microg/g Cr (47 micromol/mol Cr) for SPMA in the urine at the end of shift.</p>

High-performance liquid chromatographic determination of urinary trans, trans-muconic acid excreted by workers occupationally exposed to benzene / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the relationship between trans, trans-muconic acid (ttMA) as benzene metabolite of occupational workers and benzene concentration in air.</p><p><b>METHODS</b>A rapid and sensitive high-performance liquid chromatography was developed to determine the level of urinary ttMA. ttMA was extrated from urinary samples in liquid-liquid phase a ODS (2) (5u) column (phi 4.6 mm x 150 mm) and detected at wavelength 264 nm in a UV detector using vanillic acid as an internal standard. The mobile phase was acetaticacid/tetrahydrofuran/methanol/water (v/v, 1:2:10:87). The method was validated with 56 urine samples collected from occupationally benzene-exposed individuals.</p><p><b>RESULTS</b>A correlation coefficient (r = 0.9963) was found for ttMA ranging 0.10-10.00 microg/mL. The limit of detection was 0.10 microg/mL. The recovery and reproducibility were generally over 90%. There was a positive correlation between ttMA and benzene level in air. The equation was Y = 0.859 + 0.108C (before work, r = 0.6200) or Y = 1.980 + 0.179C (after work, r = 0.7930).</p><p><b>CONCLUSION</b>This method can be used to determine and control the level of urinary ttMA in those who are occupationally exposed to benzene.</p>