Field evaluation of a portable blood lead analyzer in workers living at a high altitude: a follow-up investigation.

BACKGROUND: Field-portable instruments can offer expeditious analytical results to health professionals in field settings and in areas lacking laboratory infrastructure. This study further evaluated an electroanalytical field-portable instrument, which rapidly analyzes blood lead concentrations. METHODS: A portable anodic stripping voltammetry (ASV) instrument was evaluated utilizing paired samples from 243 employees working at an elevation of approximately 3,800 meters in Peru. Each worker donated two venous blood samples, one of which was analyzed by the ASV device and the other by a reference analytical method, graphite furnace atomic absorption spectrometry (GFAAS). RESULTS: According to the GFAAS results, the mean blood lead concentration measured was 46(+/-16) mug/dl; this was significantly greater than the mean ASV measurement of 32(+/-11) mug/dl (paired t-test; P < 0.0001). The accuracy of the ASV estimation decreased as the measured blood lead concentration increased. CONCLUSIONS: The results from this investigation were significantly different from the previous study, which was conducted near sea level. The exact causes for the discrepancies between the portable ASV results from the two studies are unclear, but are thought to be related to differences in blood chemistry between the Midwestern United States and Peruvian Andes worker cohorts. Portable ASV blood lead measurements from populations living at high altitudes should be viewed with caution. Am. J. Ind. Med. 46:656-662, 2004. Published 2004 Wiley-Liss, Inc.

Comparison of capillary earlobe and venous blood monitoring for occupational lead surveillance.

Biological monitoring for occupational lead exposure involves routine venous blood draws from exposed employees. This uncomfortable procedure normally yields more blood than what is needed for analysis. Capillary blood sampling is less invasive but introduces the possibility of surface contamination. The objective of this study was to compare venous and capillary (earlobe) blood lead samples obtained from occupationally exposed individuals. Phlebotomists trained specifically in the collection of blood samples for lead determination collected 2 venous blood samples and 2 capillary earlobe samples from each participating employee. Before the capillary draw, the employee's earlobe was cleansed with an alcohol wipe in an effort to remove potential lead contamination. A second alcohol wipe was then used to sanitize the lancing area and was retained for lead analysis. Both the venous and capillary samples were subsequently analyzed with the use of graphite furnace atomic absorption spectrometry (GFAAS). GFAAS of venous blood specimens was considered the reference method of sampling and analysis. We collected and analyzed 126 paired earlobe and venous samples. Earlobe sampling was preferred to venous sampling by 54% of the employees surveyed. The mean difference between the capillary and venous results was 38.8 +/- 48.1 microg/dL. Lead concentrations in earlobe blood were more than twice those found in venous samples in more than half of the samples (64 of 126). Despite simple cleansing with an alcohol wipe and no visible skin contamination, 94% of the wipe samples from earlobes contained more than 1 microg of lead. Even low concentrations of contamination can significantly alter the concentration of lead in the blood; for example, sample contamination of 0.3 microg lead in a 200-microL blood sample would yield an increase of 150 microg/dL in the measured lead concentration. The findings of this study suggest that until satisfactory skin cleansing and decontamination techniques are identified and evaluated, earlobe sampling should be avoided in the surveillance of occupational blood lead levels.

Effect of perchloroethylene, smoking, and race on oxidative DNA damage in female dry cleaners.

Perchloroethylene (PERC) is used widely as an industrial dry cleaning solvent and metal degreaser. PERC is an animal carcinogen that produces increased incidence of renal adenomas, adenocarcinomas, mononuclear cell leukemia, and hepatocellular tumors. Oxidative DNA damage and lipid peroxidation were assessed in 38 women with (dry cleaners) or without (launderers) occupational exposure to PERC. PERC exposure was assessed by collecting breathing zone samples on two consecutive days of a typical work week. PERC levels were measured in blood drawn on the morning of the second day of breathing zone sample collection in dry cleaners and before a typical workday in launderers. Blood PERC levels were two orders of magnitude higher in dry cleaners compared to launderers. A significant correlation was noted between time weighted average (TWA) PERC and blood PERC in dry cleaners (r=0.7355, P<0.002). 8-Hydroxydeoxyguanosine (8-OHdG), ng/mg deoxyguanosine (dG) in leukocyte nuclear DNA was used as an index of steady-state oxidative DNA damage. Urinary 8-OHdG, microg/g creatinine was used as an index of oxidative DNA damage repair. Urinary 8-epi-prostaglandin F(2alpha) (8-epi-PGF), ng/g creatinine was used as an index of lipid peroxidation. The mean+/-S.D. leukocyte 8-OHdG in launderers was 16.0+/-7.3 and was significantly greater than the 8.1+/-3.6 value for dry cleaners. Urinary 8-OHdG and 8-epi-PGF were not significantly different between dry cleaners and launderers. Unadjusted Pearson correlation analysis of log transformed PERC exposure indices and biomarkers of oxidative stress indicated a significant association in launderers between blood PERC and day 1 urinary 8-OHdG (r=0.4661, P<0.044). No significant associations between exposure indices and biomarkers were evident in linear models adjusted for age, body mass index, race, smoking (urinary cotinine, mg/g creatinine) and blood levels of the antioxidants Vitamin E and beta-carotene. The mean+/-S.D. leukocyte 8-OHdG value in control white women was 17.8+/-7.4 and was significantly greater than the 11.8+/-5.9 in control black women. No significant differences by race were evident for the other biomarkers. Smoking status was not significantly associated with any of the oxidative damage indices. Results indicate a reduction in oxidative DNA damage in PERC exposed dry cleaners relative to launderers, but PERC could not clearly be defined as the source of the effect.

Surface sampling methods for Bacillus anthracis spore contamination.

During an investigation conducted December 17-20, 2001, we collected environmental samples from a U.S. postal facility in Washington, D.C., known to be extensively contaminated with Bacillus anthracis spores. Because methods for collecting and analyzing B. anthracis spores have not yet been validated, our objective was to compare the relative effectiveness of sampling methods used for collecting spores from contaminated surfaces. Comparison of wipe, wet and dry swab, and HEPA vacuum sock samples on nonporous surfaces indicated good agreement between results with HEPA vacuum and wipe samples. However, results from HEPA vacuum sock and wipe samples agreed poorly with the swab samples. Dry swabs failed to detect spores >75% of the time when they were detected by wipe and HEPA vacuum samples. Wipe samples collected after HEPA vacuum samples and HEPA vacuum samples collected after wipe samples indicated that neither method completely removed spores from the sampled surfaces.