Estimation of benchmark dose for micronucleus occurrence in Chinese vinyl chloride-exposed workers

In this study, we estimated the possibility of using benchmark dose (BMD) to assess the dose–response relationship between vinyl chloride monomer (VCM) exposure and chromosome damage. A group of 317 workers occupationally exposed to vinyl chloride monomer and 166 normal, unexposed control in Shandong Province northern China were examined for chromosomal damage in peripheral blood lymphocytes (PBL) using the cytokinesis-blocked micronucleus (CB-MN) assay of DNA damage. The exposed group (3.47 ± 2.65)‰ showed higher micronucleus frequency than the control (1.60 ± 1.30)‰ (P < 0.01). Occupational exposure level based on micronucleus occurrence in all individuals was analyzed with benchmark dose (BMD) methods. The benchmark dose lower limit of a one-sided 95% confidence interval (BMDL) for 10% excess risk was also determined. Results showed a dose–response relationship between cumulative exposure and MN frequency, and a BMDL of 0.54 mg/m³ and 0.23 mg/m³ for males and females, respectively. Female workers were more susceptible to MN damage than male workers.     

毛细管气相色谱法检测氯乙烯单体的含量

目的：建立毛细管色谱柱测定氯乙烯单体的方法。方法：将氯乙烯标准溶于甲醇中，易于购买、运输、保存；优化色谱条件，提高检测灵敏度。结果：在0—50mg／kg范围内具有良好线性关系，符合比尔定律，相关系数r=0．9994，方法检出限为0．05mg／kg，样品加标回收率在96．0％～100．4％之间，相对标准偏差在1．4％-4．0％之间。结论：所建立的方法简便可行，灵敏度高，具有良好的准确性和重现性。     

金属汞危害的职业流行病学研究

应用职业流行病学方法,讨论汞接触与汞危害关系,对现行汞标准进行评价。调查接汞者1220(女工776)名,对照组944(女工592)名。汞接触水平均0.1mg/m~3内,所见症状与接汞水平、尿汞、工龄与年龄有关;女工的神经系统症状发生较男工为甚。空气汞、尿汞与中毒症状间存在剂量反应关系;空气汞与尿汞值之比约1:1.67,尿汞水平在0.05mg/L以下时,接汞水平相当于0.03mg/m~3,在此汞接触水平下,连续接触10年,汞中毒发生率为1.9％。提示以保护97％接汞人群不发生中毒为水准,建议汞的卫生标准由0.01mg/m~3修订为0.03mg/m~3。     

空气中过氧化氢的四氯化钛比色法

本文叙述了一个简单快速的车间空气中过氧化氢的四氯化钛比色测定法。方法的最低检测浓度为1.0mg/m~3(采10L空气样品),批间变异系数为0.9%～4.1%(n=6,40～5mgH_2O_2/L),一个大型气泡吸收管的采样效率为100%;空气中共存的SO_2浓度不超过3mg/m~3时不干扰测定。     

城市空气监测数据与空气污染指数的相关性分析

目的评价空气污染指数(API)用于空气污染健康效应研究时与实际空气污染的符合程度。方法在广州(中山大学广州北校区内)和珠海(中山大学珠海校区内)两个监测点,用仪器连续监测获得两地空气实测数据(SO2,NO2,PM10),并用实际监测数据与当地公布的对应时间的API进行相关分析。结果实际监测数据显示两个监测点NO2、SO2及PM10的平均浓度,广州监测点分别为0.11 mg/m30、.37 mg/m30、.11 mg/m3;珠海监测点则分别为0.06 mg/m3、0.04 mg/m3和0.02 mg/m3。两个监测点的实测数据与当地API均有类似的变化趋势。将两个监测点实测数据换算为API并与当日的API数据进行相关分析,除在广州监测点NO2的实测数据与公布的API相关(r=0.91,P<0.05)以外,其余指标均未见有统计学意义的相关。结论两个监测点的空气污染实测数据与当地公布API在趋势上是相似的,但两种监测方法在数据上的相关性(一致性)不强。API应用于描述人群空气污染暴露程度时应辅以区域的实际监测数据。     

二硫化碳对女工性腺机能影响的研究

本文研究了我国目前生产条件下CS_2对女工性腺机能的影响。以某人造丝厂纺丝车间女工151人及对照组女工145人为研究对象。作业场所空气中CS_2的平均浓度为6.7～32.0mg/m~3。接触CS_2女工月经异常发生率为55.6%,显著高于对照组(38.6%),P<0.01。以周期异常占首位。接触CS_2浓度低于10mg/m~3的女工也可出现月经异常,CS_2作业女工绝经年龄提前,早发绝经及更年期综合征较对照组增多。早期自然流产(妊娠小干8周)的发生事显著高于对照组,P<0.05。     

接触叠氮酸作业工人的健康危害研究

对31名起爆药三硝基间苯二酚与叠氮化铅共沉淀结晶(D.S共晶)作业工人进行了临床检查;测定了生产场所HN_3浓度,多数低于0.5mg/m~2,少数高于10mg/m~3。工人工作2～18年,头痛、多梦、眼和咽刺激及血压降低明显多于对照组,但未见其器官性损害。工人短时间接触高浓度HN_3(12.8mg/m~3)有自觉不适,脱离接触后迅速消失。结合亚慢性HN_3吸入毒性,提出HN_3和NaN_3最高容许浓度各为0.2mg/m~3和0.3mg/m~3。     

氯乙烯职业病危害及控制的研究进展

氯乙烯对暴露人群健康的危害是多方面的,除了氯乙烯急性中毒外,流行病学资料显示,氯乙烯主要是对肝脏、神经系统、消化系统和生殖系统等的危害,并引起肢端溶骨症。氯乙烯接触限值各国也不相同,目前,我国车间空气中氯乙烯的时间加权平均容许浓度为30mg／m3,我国2002规定的氯乙烯生物接触限值为工作周末的班末尿中三氯乙酸0．3mmol／L（50mg／L）。     

Long-term efficacy of single-dose oral treatment in schistosomiasis haematobium

A two-year follow-up was conducted in children who had been the subjects of a six-month double-blind trial in the single-dose treatment of Schistosoma haematobium infection. The trial had assessed therapeutic efficacy of three oral preparations—praziquantel 40 mg/kg, metrifonate 10 mg/kg, and the “combination” (concurrent niridazole 25 mg/kg and metrifonate 10 mg/kg administration).Reduction in urinary egg excretion remained high up to follow-up at two years, based on a comparison of pre- and post-treatment geometric mean counts—praziquantel 96·9% (n = 96 at six months, 51 at two years); the ‘combination’ 93·9% (n = 97 at six months, 48 at two years); and metrifonate 90·3% (n = 92 at six months, 49 at two years). The differences in percentage reduction were not significant (p>0·1). However, a significantly greater reduction in egg ouput was produced by praziquantel (81·7%) and the ‘combination’ (82·5%) than by metrifonate (54·2%), on comparing pre- and post-treatment arithmetic mean counts (p<0·01).A significantly smaller percentage of subjects were excreting ≥125 ova/10 ml urine two years after treatment with praziquantel (10·3%), compared to treatment with the ‘combination’ (25·7%) and metrifonate (35·8%) (p<0·01). The cure rate was significantly higher in the praziquantel group (47·4%) compared to the ‘combination’ (24·7%) and metrifonate (17·4%) groups, for the six to 24-month follow-up period (p<0·001).The pattern and level of transmission had contributed to the long-term efficacy recorded in this study.