Lung cancer among industrial sand workers exposed to crystalline silica

In 1997, the International Agency for Research on Cancer determined that crystalline silica was a human carcinogen but noted inconsistencies in the epidemiology. There are few exposure-response analyses. The authors examined lung cancer mortality among 4,626 industrial sand workers, estimating exposure via a job-exposure matrix based on 4,269 industrial hygiene samples collected in 1974--1995. The average length of employment was 9 years, and estimated average exposure was 0.05 mg/m(3) (the National Institute of Occupational Safety and Health Recommended Exposure Limit). Results confirmed excess mortality from silicosis/pneumoconioses (standardized mortality ratio = 18.2, 95% confidence interval: 10.6, 29.1; 17 deaths). The lung cancer standardized mortality ratio was 1.60 (95% confidence interval: 1.31, 1.93; 109 deaths). Limited data suggested that smoking might account for 10--20% of the lung cancer excess. Exposure-response analyses by quartile of cumulative exposure (15-year lag) yielded standardized rate ratios of 1.00, 0.78, 1.51, and 1.57 (p for trend = 0.07). Nested case-control analyses after exclusion of short-term workers, who had high overall morality, yielded odds ratios by quartile of cumulative exposure (15-year lag) of 1.00, 1.35, 1.63, and 2.00 (p for trend = 0.08) and odds ratios by quartile of average exposure of 1.00, 0.92, 1.44, and 2.26 (p = 0.005). These data lend support to the labeling by the International Agency for Research on Cancer of silica as a human carcinogen. There are approximately 2 million US workers exposed to silica; 100,000 are exposed to more than 0.1 mg/m(3).     

Urinary lead as a possible surrogate of blood lead among workers occupationally exposed to lead

Objectives: The aim of the present study is to investigate whether lead (Pb) in urine (Pb-U) can be a valid surrogate of lead in blood (Pb-B), the traditional biomarker of exposure to lead in occupational health. Methods: Blood and spot urine samples were collected from 258 workers of both sexes occupationally exposed to lead. The samples were analyzed for lead by graphite furnace atomic absorption spectrometry, and the correlation between Pb-B and Pb-U was examined by linear regression analysis before and after logarithmic conversion. Results: The correlation coefficient (0.824; P < 0.01) was largest when the relationship between Pb-B and Pb-U was examined with 214 cases of one sex (i.e., men) after Pb-U was corrected for a specific gravity (1.016) of urine (Pb-Usg) and both Pb-B and Pb-Usg were converted to logarithms. The geometric means (GMs) of Pb-B and Pb-Usg for the 214 men were 489 μg/l and 81 μg/l, respectively. When Pb-Usg was assumed to be 100 μg/l in this set of correlations, the 95% confidence range of Pb-B for the group mean was narrow, i.e., 543–575 μg/l (with GM of 559 μg/l), whereas that for individual Pb-B values was as wide as 355–881 μg/l. Conclusions: The correlation of Pb-U with Pb-B among workers occupationally exposed to Pb was close enough to suggest that Pb-U may be a good alternative to Pb-B on a group basis, but not close enough to allow Pb-U to predict Pb-B on an individual basis. Received: 6 April 1999 / Accepted: 17 July 1999     

Biomass power plants and health problems among nearby residents: A case study in Thailand

Objectives

Electricity generation from biomass has become a boom business. However, currently, concerns over their environmental and health impact have emerged. This study aimed to explore these health problems by studying two small biomass power plants in Thailand.

Materials and Methods

Data concerning chronic diseases and health symptoms was collected from 392 people by trained interviewers by the use of a questionnaire.

Results

Residents living within 1 km from the power plants had a higher prevalence of allergies (Odds ratio = 2.4, 95% CI: 1.5–4.0), asthma (OR = 2.1, 95% CI: 1.0–4.4) and chronic obstructive pulmonary disease (COPD) (OR = 2.7, 95% CI: 1.0–8.4). The risks of other symptoms, itching/rash, eye irritation, cough, stuffy nose, allergic symptoms, sore throat, and difficulty breathing among those living within 0.5 km from the power plants (OR = 2.5–8.5) were even more marked.

Conclusions

It has been concluded that without a proper control, pollution from the biomass power plants can cause significant health problems to the nearby residents.     

职业性铅暴露人群血铅的危险因素研究

目的探讨职业铅暴露人群血铅的危险因素,为采取针对性的防控措施提供科学依据。方法选择余姚市蓄电池工厂227名工人作为研究对象,采用统一调查表对个人职业史、生活习惯、教育程度等进行调查,同时进行血铅和车间空气中铅浓度测定。在此基础上,分别采用单因素、多因素条件logistic回归分析筛选血铅的关联因素,P<0.05为差异有统计学意义。结果本研究共设29个检测点,仅5个点合格,合格率17.24%,工人平均血铅水平为(578.54±175.56)μg/L。单因素条件logistic回归分析显示性别、吸烟、户籍、文化程度和车间空气铅浓度等变量均可影响血铅浓度。多因素条件logistic回归分析显示车间空气铅浓度和户籍差异有统计学意义。结论工作场所铅浓度较高,工人血铅普遍较高,车间空气铅浓度和户籍是血铅增高的危险因素。     

Lung function and exposure to asbestos among vehicle mechanics.

Vehicle mechanics (n = 99) exposed to asbestos (annual median value 0.08 f/ml), and local controls (n = 83) not occupationally exposed to asbestos were studied with regard to symptoms and pulmonary function. The inclusion criteria to participate in this study was an age of at least 40 years with no known exposure to lung irritating agents, and for the exposed subjects, more than 15 years occupational exposure to asbestos with at least 20 years from the first exposure. The subjects were studied during identical conditions by means of dynamic and static spirometry, single breath wash-out with nitrogen (N2) and carbon monoxide (CO). The median for cumulative exposure of asbestos during the entire work life among the studied mechanics was 2.3 f*y/ml. The mechanics had reduced transfer factor (TLCO), after adjustment for age, height, and smoking category. A significant dose-response relationship was noted between the cumulative exposure of asbestos and CV%. The findings suggest a slight influence of small airways and alveoli. The evaluation of the prognostic significance of this requires a longitudinal study.     

杭州市居民膳食铅、镉摄入水平分析

目的 了解浙江省杭州市居民膳食铅、镉摄入情况,为开展相关膳食安全性评价提供科学依据。方法 采用3 d食物称重法和3 d 24 h回顾法收集1744名调查对象食物消费量数据,检测烹调后代表性食物样品中的铅、镉含量,计算个人摄入量并与相应摄入限值进行比较。结果 杭州市居民每周膳食铅摄入量中位数为0.0092 mg/kgbw,为铅暂定每周可耐受摄入量(PTWI)的37.0%;每月膳食镉摄入量中位数为0.00093~0.0053 mg/kgbw,占镉暂定每月可耐受摄入量(PTMI)的3.7%~21.0%;各年龄组铅、镉摄入量总体存在差异(均P<0.001),其中未成年人铅摄入量中位数为0.011 mg/kgbw,镉摄入量中位数为0.00077~0.016 mg/kgbw,均高于其他各年龄组(均P<0.008,多次两两比较调整后α值);谷类食物对个体膳食铅、镉摄入贡献率最高,分别为78.9%和44.8%。结论 杭州市居民膳食铅、镉摄入量总体处于安全水平,但儿童青少年的摄入量较成人偏高,应引起重视。     

Trend of blood lead levels in children in an industrial complex and its suburban area in Ulsan,Korea

OBJECTIVES: To study the difference in blood lead level of children living in an industrial complex and those in a suburban area in Ulsan, Korea, and to investigate the trend by age and year. METHODS: The study subjects consisted of 620 children living in an industrial complex and 298 children living in a suburban area of Ulsan, Korea. We analyzed their blood lead levels, using an atomic absorption spectrometer with a graphite furnace, bi-annually from 1997 to 2001. RESULTS: The geometric mean levels of blood lead in children living in the industrial complex were 5.10 microg/dl, 5.36 microg/dl, and 5.41 microg/dl in the years 1997, 1999, and 2001, respectively, whereas those of children living in the suburban area were 3.81 microg/dl, 4.75 microg/dl, and 4.93 microg/dl, respectively. There was an increasing trend in the blood lead levels of children, and the differences in the levels of children living in the industrial complex and in the suburban area decreased year by year. CONCLUSIONS: These results suggest that the amount of exposure to lead in children is increasing from year to year in Ulsan, Korea.     

Relationship between blood lead levels and renal function in lead battery workers

OBJECTIVES: The aim of this study was to investigate the correlation between blood lead (PbB) levels and renal function indices of blood-urea nitrogen (BUN), serum creatinine (SC) and uric acid (UA) among lead battery workers with exposure to lead. METHODS: A total of 229 workers of both genders from two lead battery factories were recruited in this cross-sectional study. The personal airborne and blood samples were collected on the same day. The airborne lead (PbA) and PbB levels, and individual renal function parameters were measured and statistically analyzed. RESULTS: A positive correlation between PbB levels and individual renal function index of BUN, SC, and UA was found ( P<0.01). The PbB levels and renal function indices showed significant difference between male and female workers. Based on a multiple regression model, an increment of 10 micro g/dl PbB produced an increase of 0.62 mg/dl BUN, after being adjusted for work duration and age, and an increase of 0.085 mg/dl UA, after being adjusted for gender and body weight. Workers with PbB 60 microg/dl showed a positive dose-effect relationship with significant difference in BUN ( P<0.001) and UA ( P<0.05), and the percentage of workers with BUN and UA over the reference value also showed an increasing trend. CONCLUSION: Blood-urea nitrogen and uric acid could be considered as suitable prognostic indicators of renal dysfunction in lead-exposed workers. Our results showed that PbB levels higher than 60 micro g/dl had increasing chances of inducing adverse renal effects.     

基于IEUBK模型研究环境铅对婴儿血铅的影响

目的利用环境铅、出生前铅暴露数据和暴露吸收生物动力学模型(IEUBK模型),探讨环境铅对婴儿6月龄时血铅浓度的影响。方法利用2005-2007年的出生队列资料、出生前铅暴露数据和婴儿6月龄时血铅浓度值,以及婴儿居住环境土壤、大气和饮用水等介质中的铅检测数据,基于IEUBK模型计算环境铅引起的婴儿血铅增高水平。结果婴儿出生前就存在铅暴露,孕晚期母亲血铅浓度几何均数为(40.3±3.7)μg/L,6月龄婴儿的血铅浓度的几何均数为(54.7±6.7)μg/L,有17.3%的婴儿血铅浓度超过100μg/L。研究对象居住环境中多种介质均能检测到铅,土壤、大气和饮水中铅的几何均数浓度分别为45.57mg/kg、0.023μg/m3和3.25μg/L。根据IEUBK模型计算的由环境铅及出生前铅暴露引起的婴儿6月龄血铅浓度几何均数值为12.4μg/L,占其实际血铅浓度的22.7%。结论研究区域婴儿仍存在较高水平的血铅暴露,其居住环境内存在一定程度的铅污染现象。除环境铅外,当地婴儿可能还存在其他的铅暴露来源。     

A study of the relationship between ambient lead and blood lead among lead battery workers

 Objective: To examine the relationship between ambient lead levels and blood lead levels and to explore the modifiers of the relationship between ambient lead and blood lead. Method: A cross-sectional study was conducted in two lead battery factories. Blood lead level and ambient lead concentration were measured for each participant concurrently. A structured questionnaire was administered to collect sociodemographic characteristics and occupational history. Design: Biological and personal environmental measurements of 219 lead-exposed workers were analyzed by both simple and multiple linear regression. A regression model was selected for interpretation. Results: A high correlation (r=0.62) between ambient lead (PbA) and blood lead (PbB) was observed. In addition, numerous factors, including age, sex, alcohol consumption, personal hygiene practice and type of lead exposure, were also found to influence blood lead levels. Although PbB was highly correlated with PbA, blood lead level may not be effectively lowered by reducing ambient lead level. Based on the regression coefficients, improvement of hygienic practice was more effective at lowering PbB than reducing ambient lead level. Good hygienic practice may be the preferential way to reduce lead exposure in current conditions. Conclusion: Education of correct work practice may be more important than engineering control in the developing countries to lower blood lead levels in lead battery factories. Received: 28 May 1996/Accepted: 30 August 1996     

Association between blood lead and sociodemographic parameters among children

OBJECTIVE: To determine the relationship between blood lead concentration (Pb-S), and sociodemographic parameters among children. METHODS: Blood lead concentration (Pb-S) was determined in 243 children (aged 5.94 +/- 2.78 years) in the district of Valencia. The required analysis was performed at the Center for Toxicological Investigations of University of Carabobo (CITUC), Venezuela, between January 1st, 1998 to December 31st, 2000. Geographical Information Systems (GIS) technology was used for data mapping. RESULTS: Average Pb-S (11.62 ug/dl) was significantly higher than the allowed levels. One hundred and fifty (61.7%) children had Pb-S levels above the allowed concentration (VSLP) and this amount was significantly high in relation to the total number of subjects studied. The logistic regression analysis showed a significant association of sectors 12 (status A) and 16 and 28 (status C) with VSLP (R=0.1189; p<0,01; R=0.1202, p<0,01 and R=0.1189; p<0.01, respectively). Odds ratio showed that children from status C are 7,286 times more likely to have Pb-S VSLP than those from A or B. CONCLUSIONS: This study confirms that SGI and epidemiological-statistical methods widen the possibilities of preventing contaminants' adverse health effects. It also shows that correlating geographical and health data has allowed to identifying "high risk" areas, leading to a pro-active public health action     

铅作业工人血红蛋白与血铅水平关系的探讨

为了解本市长期低浓度铅接触工人的健康状况,进一步分析低浓度铅接触对人体的影响,我们在本市对这类工人进行了一次调查,现将结果报道如下。     

某工业区居民铅内外暴露相关性研究

通过环境中铅的多途径暴露健康风险评估及居民体内铅负荷水平检测,探讨某工业区居民铅内外暴露的相关性及内暴露的影响因素.结果显示,该工业区环境中铅的总非致癌风险为0.08,低于非致癌风险可接受水平1;居民尿铅、血铅几何均数分别为0.81、18.43 μg/L,年龄和吸烟对人体内铅负荷有影响.提示铅的内暴露水平与外暴露健康风...