Lead use in California industry: its prevalence and health implications

Survey of current lead use, handling, hygiene, and contaminant controls among New Jersey industries

In 2003, a chemical handling and use survey was mailed to New Jersey employers identified as currently using lead in their industrial processes. This survey was used to ascertain characteristics about lead use, handling, and protection of employees during manufacturing operations. The survey included a diverse group of current lead users with a total lead use range from less than 1 pound to more than 63 million pounds of lead per year. The survey allowed for a comprehensive characterization of hazards and protective measures associated with this metal, still commonly used in many products and industrial processes. Forty-five surveys were returned by companies that are listed in the New Jersey Adult Blood Lead Registry, which is part of the New Jersey Adult Blood Lead Epidemiology and Surveillance (ABLES) program. This program records and investigates cases of adults with greater than 25 mu g/dL of lead in their blood; most cases are related to occupational exposures. This survey found that greater than 25% of these surveyed companies with significant potential for lead exposure did not employ commonly used and basic industrial hygiene practices. In addition, the survey found that 24% of these companies had not conducted air sampling within the last 3 years. Air sampling is the primary trigger for compliance with the Occupational Safety and Health Administration (OSHA) general industry lead standard. Only 17% of the companies have ever been cited for a violation of the OSHA lead standard, and only 46% of these companies have ever had an OSHA inspection. State-based surveillance can be a useful tool for OSHA enforcement activities. Elevated blood lead values in adults should be considered as a trigger for required compliance with an OSHA general industry lead standard.

Whole-body lifetime occupational lead exposure and risk of Parkinson's disease

BACKGROUND

Several epidemiologic studies have suggested an association between Parkinson's disease (PD) and exposure to heavy metals using subjective exposure measurements.

OBJECTIVES

We investigated the association between objective chronic occupational lead exposure and the risk of PD.

METHODS

We enrolled 121 PD patients and 414 age, sex, and race, frequency-matched controls in a case-control study. As an indicator of chronic Pb exposure, we measured concentrations of tibial and calcaneal bone Pb stores using 109Cadmium excited K-series X-ray fluorescence. As an indicator of recent exposure, we measured blood Pb concentration. We collected occupational data on participants from 18 years of age until the age at enrollment, and an industrial hygienist determined the duration and intensity of environmental Pb exposure. We employed physiologically based pharmacokinetic modeling to combine these data, and we estimated wholebody lifetime Pb exposures for each individual. Logistic regression analysis produced estimates of PD risk by quartile of lifetime Pb exposure.

RESULTS

Risk of PD was elevated by > 2-fold [odds ratio = 2.27 (95% confidence interval, 1.13-4.55); p = 0.021] for individuals in the highest quartile for lifetime lead exposure relative to the lowest quartile, adjusting for age, sex, race, smoking history, and coffee and alcohol consumption. The associated risk of PD for the second and third quartiles were elevated but not statistically significant at the alpha = 0.05 level.

CONCLUSIONS

These results provide an objective measure of chronic Pb exposure and confirm our earlier findings that occupational exposure to Pb is a risk factor for PD.

Lead exposure in radiator repair workers: a survey of Washington State radiator repair shops and review of occupational lead exposure registry data

Radiator repair workers in Washington State have the greatest number of very elevated (> or =60 microg/dL) blood lead levels of any other worker population. The goals of this study were to determine the number of radiator repair workers potentially exposed to lead; estimate the extent of blood lead data underreporting to the Occupational Lead Exposure Registry; describe current safety and health practices in radiator repair shops; and determine appropriate intervention strategies to reduce exposure and increase employer and worker awareness. Lead exposure in Washington State's radiator repair workers was assessed by reviewing Registry data and conducting a statewide survey of radiator repair businesses. This study revealed that a total of 226 workers in Washington State (including owner-operators and all employees) conduct repair activities that could potentially result in excessive exposures to lead. Approximately 26% of radiator repair workers with elevated blood lead levels (> or =25 microg/dL) were determined to report to Washington State's Registry. This study also revealed a lack of awareness of lead's health effects, appropriate industrial hygiene controls, and the requirements of the Lead Standard. Survey respondents requested information on a variety of workplace health and safety issues and waste management; 80% requested a confidential, free-of-charge consultation. Combining data derived from an occupational health surveillance system and a statewide mail survey proved effective at characterizing lead exposures and directing public health intervention in Washington State.

Lead exposure among small-scale battery recyclers, automobile radiator mechanics, and their children in Manila, the Philippines

Blood lead (PbB) and hemoglobin levels (Hb) were determined in 40 battery repair/recycling shop workers, 16 radiator repair shop workers, and 20 children living in the immediate vicinity of these shops. Unexposed residents with similar socioeconomic status were also investigated. Mean PbB level was significantly higher for battery workers (54.23 microg/dL) when compared to radiator workers (20.04 microg/dL) and unexposed adults (12.56 microg/dL) (P<0.001). Among battery workers, 94% had PbB levels above the WHO permissible exposure limit of 40 microg/dL for males and 30 microg/dL for females. There was no demarcation between workplace and living quarters; therefore, workers' families were similarly exposed to hazards. Children living in the immediate vicinity of battery shops also had significantly higher mean PbB levels (49.88 microg/dL) compared to radiator shop children (11.84 microg/dL) and unexposed children (9.92 microg/dL). For workers with PbB > 40 microg/dL, 90% were anemic (Hb < 13 g/dL for males and <11.5 g/dL for females). Linear regression showed a correlation (r=-0.214; P=0.03) between Hb level and log(10)PbB. There was no significant relationship between anemia and blood lead in children (r=-0.146). We conclude that radiator repair activities appeared to increase the body burden of lead, although not up to a level significantly different from unexposed counterparts. Battery recycling/repair activities, however, significantly increased blood lead levels in workers and their children.

Occupational case-control studies: II. Recommendations for exposure assessment

Obtaining valid and reliable quantitative exposure estimates is a significant challenge in community-based case-control studies in part, because industrial hygiene monitoring data are usually not available and detailed information on the job and work environment is usually not systematically obtained or assessed. To improve the quality and credibility of disease risk information obtained from occupational case-control studies, we recommend that standardized exposure assessment methods be used to derive quantitative exposure estimates. We identify sources of variation inherent to the assessment process, including: the quality of the information reported on the job, industry, activities, and materials; the industrial hygienist's familiarity with the reported job/industry; the probability that the job/industry was exposed, which depends on plant preferences for particular substances, on process technology, and on customer specifications; and variability in workplace characteristics. To improve the reliability of estimating job-related exposures both within and between studies, we recommend that the epidemiologic analyses be conducted with and without data rated to be of poor quality; that contact be made with experts when the study industrial hygienist is unfamiliar with the manufacturing process in question; that existing data bases be used to estimate the probability of exposure; that a data base be developed that describes manufacturing processes; and that explicit criteria based on industrial hygiene principles be used to evaluate workplace characteristics. In addition, a procedure is described for deriving quantitative exposure estimates by using a reference scale of frequently monitored jobs with their associated mean exposure levels. Areas of research are identified to improve exposure assessment in community-based case-control studies.