Personnel Elements of Good Laboratory Practices

Abstract

This study examined blood lead and creatine kinase levels in a group of 24 Australian Aboriginal males admitted to the hospital for treatment of severe petrol sniffing related illness after using only leaded petrol and 27 sniffers, 16 ex-sniffers and 13 non-sniffers from an isolated Aboriginal community using only unleaded petrol. Creatine kinase levels (which were nearly all creatine kinase-skeletal muscle isoenzyme indicating skeletal muscle damage) were correlated with blood lead levels and were elevated in active sniffers of leaded petrol on admission to hospital but were also increased in those sniffing unleaded petrol in the remote community. After fourteen days in hospital, median creatine kinase levels of leaded petrol sniffers dropped rapidly to levels similar to those of ex-sniffers and non-sniffers while median blood lead levels decreased but still remained higher than the other three groups. The data suggest that elevated creatine kinase associated with petrol sniffing may be due to compounds in petrol other than the lead additives, possibly volatile hydrocarbon components. Elevated creatine kinase may be useful in detecting current petrol sniffing activity, particularly in locations using unleaded petrol.     

A geospatial analysis of the effects of aviation gasoline on childhood blood lead levels

Background: Aviation gasoline, commonly referred to as avgas, is a leaded fuel used in small aircraft. Recent concern about the effects of lead emissions from planes has motivated the U.S. Environmental Protection to consider regulating leaded avgas.Objective: In this study we investigated the relationship between lead from avgas and blood lead levels in children living in six counties in North Carolina.Methods: We used geographic information systems to approximate areas surrounding airports in which lead from avgas may be present in elevated concentrations in air and may also be deposited to soil. We then used regression analysis to examine the relationship between residential proximity to airports and North Carolina blood lead surveillance data in children 9 months to 7 years of age while controlling for factors including age of housing, socioeconomic characteristics, and seasonality.Results: Our results suggest that children living within 500 m of an airport at which planes use leaded avgas have higher blood lead levels than other children. This apparent effect of avgas on blood lead levels was evident also among children living within 1,000 m of airports. The estimated effect on blood lead levels exhibited a monotonically decreasing dose–response pattern, with the largest impact on children living within 500 m.Conclusions: We estimated a significant association between potential exposure to lead emissions from avgas and blood lead levels in children. Although the estimated increase was not especially large, the results of this study are nonetheless directly relevant to the policy debate surrounding the regulation of leaded avgas.     

Childhood Lead Exposure After the Phaseout of Leaded Gasoline: An Ecological Study of School-Age Children in Kampala,Uganda

Background

Tetraethyl lead was phased out of gasoline in Uganda in 2005. Recent mitigation of an important source of lead exposure suggests examination and re-evaluation of the prevalence of childhood lead poisoning in this country. Ongoing concerns persist about exposure from the Kiteezi landfill in Kampala, the country’s capital.

Objectives

We determined blood lead distributions among Kampala schoolchildren and identified risk factors for elevated blood lead levels (EBLLs; ≥ 10 μg/dL).

Analytical approach

Using a stratified, cross-sectional design, we obtained blood samples, questionnaire data, and soil and dust samples from the homes and schools of 163 4- to 8-year-old children representing communities with different risks of exposure.

Results

The mean blood lead level (BLL) was 7.15 μg/dL; 20.5% of the children were found to have EBLL. Multivariable analysis found participants whose families owned fewer household items, ate canned food, or used the community water supply as their primary water source to have higher BLLs and likelihood of EBLLs. Distance < 0.5 mi from the landfill was the factor most strongly associated with increments in BLL (5.51 μg/dL, p < 0.0001) and likelihood of EBLL (OR = 4.71, p = 0.0093). Dust/soil lead was not significantly predictive of BLL/EBLL.

Conclusions

Lead poisoning remains highly prevalent among school-age children in Kampala. Confirmatory studies are needed, but further efforts are indicated to limit lead exposure from the landfill, whether through water contamination or through another mechanism. Although African nations are to be lauded for the removal of lead from gasoline, this study serves as a reminder that other sources of exposure to this potent neurotoxicant merit ongoing attention.     

无铅汽油染毒对小鼠神经行为和神经递质的影响

目的 研究汽油染毒对小鼠神经行为和单胺类神经递质及其代谢产物的影响。方法 选用80只昆明小鼠，随机分成4组，用无铅汽油静式染毒90d，分别于染毒前和染毒第30、60、90天时测定其自由活动情况及学习和记忆能力，并于染毒第90天时测定其纹状体中儿茶酚胺类神经递质及尿中其代谢产物含量。结果 染毒60d后小鼠自由活动计数增加；染毒30d后水迷宫和跳台法学习能力均下降，且都存在剂量一效应关系；染毒90d后中、高剂量组纹状体单胺类神经递质及尿中单胺类神经递质代谢产物含量均下降。结论 长期无铅汽油接触可以引起小鼠神经行为的改变，其机制可能与单胺类神经递质及其代谢产物的含量减少有关。     

我国禁用含铅汽油后儿童血铅水平的变化

目的 描述禁用含铅汽油后中国儿童血铅水平及其变化趋势.方法 通过计算机检索中国生物医学文献数据库和中国全文期刊数据库及相关文献追溯等途径,收集国内1994-2008年公开发表的儿童血铅水平研究的论文,选取标准如下:(1)选用原子吸收分光光度法(石墨炉及其它原子吸收分光光度法)或者电感耦合等离子体质谱法;(2)有严格的质量控制;(3)样本量大于100人;(4)儿童年龄为0～14岁;(5)被调查儿童居住地无明显铅污染,最终有93篇文献入选.同时按同样的标准选取居住在农村地区的儿童血铅文献27篇,按标准(1)～(4)选取居住在工业区的儿童血铅文献19篇.并将入选的全国儿童血铅文献按照调查时间分为4类:(1)禁用含铅汽油前;(2)禁用含铅汽油后第一阶段(2002年之前);(3)禁用后第二阶段(2003-2005年);(4)禁用后第三阶段(2006-2008年).结果 禁用含铅汽油前全国儿童血铅平均值为98.21 μg/L,铅中毒率为37.34％;禁用含铅汽油后三阶段的血铅均值分别为85.02、83.63、61.82 μg/L,铅中毒率分别是27.68％,25.97％,10.90％.禁用含铅汽油前农村儿童血铅均值为87.53 μg/L,铅中毒率为28.40％;禁用后分别为72.23 μg/L,17.85％;禁用含铅汽油前工业区儿童血铅均值为110.76 μg/L,禁用后下降为106.77 μg/L.结论 禁用含铅汽油后,全国儿童和农村儿童血铅水平明显下降,工业区略有下降,但依然高于发达国家,提示在我国控制铅污染,减少儿童铅暴露仍任重而道远.     

Visits to Physicians after the Oxygenation of Gasoline in Philadelphia

During the period between 1992 and 1997, there was an increase in levels of methyl tertiary butyl ether (MTBE) in gasoline in the Philadelphia, Pennsylvania, area. In this study, the authors analyzed billing records from clinical practices that were extensions of the University of Pennsylvania. The authors based their selections on the International Classification of Diseases-9 diagnostic codes, which were determined from (1) previous studies of methyl tertiary butyl ether conducted by the Centers for Disease Control; (2) respiratory symptoms, including asthma and wheezing; and (3) symptoms associated anecdotally with methyl tertiary butyl ether levels in gasoline. The authors normalized all data by the total number of office visits. The incidences of headache, throat irritation, allergic rhinitis, cough, nausea, dizziness, upper respiratory infections, wheezing, otitis media, skin rash, anxiety, insomnia, palpitations, generalized allergy, and malaise were increased during the period studied. Large increases occurred during the winters of 1993–1994 and 1994–1995 (during which there were high levels of MTBE), but not in the preceding summers (during which there were low levels of MTBE). This was especially true for asthma and wheezing. During the summers of 1995, 1996, and 1997, the incidences of the aforementioned symptoms increased greatly.     

Ventilatory Capacity and Lung Volumes of US Coal Miners

Between 1969 and 1971 the lung volumes and ventilatory capacity of 9, 076 US coal miners were determined. In miners with simple coal workers’ pneumoconiosis, no relationship existed between ventilatory capacity and radiographic category. However, complicated pneumoconiosis led to definite ventilatory impairment, in contrast, residual volume showed a slight increase with increasing radiographic category of simple pneumoconiosis.

Significant geographic variations in ventilatory capacity and lung volumes occurred that appeared to be related, partly to the type of coal dust to which the miners were exposed, partly to the ethnic origin of the miners, and partly to other miscellaneous nonoccupational factors.

While the occupation of coal mining may, in certain instances, lead to very minor reductions of ventilatory capacity, such reductions are minimal in the absence of complicated pneumoconiosis and would not be associated with respiratory disability.     

Blood Lead Survey of Children,Pregnant Women,Professional Drivers,Street Workers,and Office Workers in Trujillo,Peru

In this pilot study, conducted in summer 2002, the authors measured blood lead levels (BLLs) for 118 subjects in the city of Trujillo, Peru, where leaded gasoline is in the process of being phased out. Subjects included bus drivers, combi (minivan) drivers, street vendors, newspaper vendors, traffic police, taxi drivers, gas station attendants, children living both near and distant from gas stations, pregnant women, and office workers (controls). The highest BLLs were 9.2 μg/dl and 9.3 μg/dl from a child who lived near a gas station and from a traffic policeman, respectively; however, all BLLs were below the U.S. Centers for Disease Control and Prevention's advisory level of concern (10 μg/dl). Office workers (n = 8) and pregnant women (n = 36) had significantly lower BLLs (geometric mean ± standard deviation = 2.1 ± 0.7 μg/dl, p < 0.022; and 2.5 ± 1.1 μg/dl, p < 0.008, respectively) than total traffic-exposed workers (n = 48; 3.2 ± 1.8 μg/dl). BLLs of children living near gas stations (n = 17; 3.7 ± 2.2 μg/dl) were marginally higher (p = 0.07) than for children not living near gas stations (n = 9; 2.9 ± 1.1 μg/dl). The study was limited by small sample size and the fact that the data were based on a convenience sample not fully representative of the cohorts studied. Nevertheless, the authors' findings suggest that leaded gasoline use in Trujillo continues to affect BLLs in traffic-exposed populations.     

A retrospective mortality study within operating segments of a petroleum company.

This retrospective mortality study was conducted among 34,597 oil industry workers in diverse operating segments. Employees were traced through Statistics Canada, and overall mortality (SMR = 0.85) was lower than general population rates and similar to other petrochemical cohorts. The most notable finding was a significant excess of malignant melanoma [observed deaths (N) = 16, SMR = 1.87, 95% CI = 1.07, 3.04], which concentrated among upstream workers (N = 6, SMR = 6.00, 95% CI = 2.19, 13.06), and was directly related to employment duration and latency. Specific substances or hydrocarbon (HC) streams could not be implicated, although possible explanations include dermal HC exposure, ultraviolet light exposure, or a synergistic effect between these two factors. Marketing/transportation workers showed a non-significant excess of multiple myeloma (SMR = 1.81), which was also related to employment duration, latency, and commencement of employment before 1950. Lymphatic cancer, skin cancer, and kidney cancer mortality was not elevated in refinery workers, a finding at odds with some previous refinery worker studies. Although the malignant melanoma and possibly the multiple myeloma mortality patterns are consistent with an occupational link, further studies are needed to investigate the relationship of these diseases with particular exposures.     

Mutagenicity and in vivo toxicity of combined particulate and semivolatile organic fractions of gasoline and diesel engine emissions.

Exposure to engine emissions is associated with adverse health effects. However, little is known about the relative effects of emissions produced by different operating conditions, fuels, or technologies. Rapid screening techniques are needed to compare the biological effects of emissions with different characteristics. Here, we examined a set of engine emission samples using conventional bioassays. The samples included combined particulate material and semivolatile organic compound fractions of emissions collected from normal- and high-emitter gasoline and diesel vehicles collected at 72 degrees F, and from normal-emitter groups collected at 30 degrees F. The relative potency of the samples was determined by statistical analysis of the dose-response curves. All samples induced bacterial mutagenicity, with a 10-fold range of potency among the samples. Responses to intratracheal instillation in rats indicated generally parallel rankings of the samples by multiple endpoints reflecting cytotoxic, inflammatory, and lung parenchymal changes, allowing selection of a more limited set of parameters for future studies. The parameters selected to assess oxidative stress and macrophage function yielded little useful information. Responses to instillation indicated little difference in potency per unit of combined particulate material and semivolatile organic compound mass between normal-emitter gasoline and diesel vehicles, or between emissions collected at different temperatures. However, equivalent masses of emissions from high-emitter vehicles of both types were more potent than those from normal-emitters. While preliminary in terms of assessing contributions of different emissions to health hazards, the results indicate that a subset of this panel of assays will be useful in providing rapid, cost-effective feedback on the biological impact of modified technology.