Skin contamination and low airborne nickel exposure of electroplaters

Cancer mortality and exposure to nickel and chromium compounds in a cohort of Italian electroplaters

BACKGROUND

Nickel and chromium-VI compounds are carcinogens for lung cancer, although it is still debated if there is an increased risk at low levels of exposure and for other cancers.

METHODS

In a cohort of 2991 Italian electroplaters, a proportion of whom were exposed to low levels of nickel and/or chromium, cumulative exposure to their compounds was obtained by multiplying average concentrations of the metals in each electroplating tank by duration of employment in the company. The association of exposure to compounds with mortality was assessed by multivariable Cox models.

RESULTS

No cancer site was associated with chromium exposure controlling for nickel, whereas exposure to nickel significantly increased mortality from lung, rectal, and kidney cancers, even after adjusting for exposure to chromium.

CONCLUSIONS

Study results suggest that exposure to nickel compounds may increase the risk of lung cancer even below its occupational exposure limit and indicate possible associations with other cancer sites.

Reliability and validity of expert assessment based on airborne and urinary measures of nickel and chromium exposure in the electroplating industry

The reliability and validity of six experts' exposure ratings were evaluated for 64 nickel-exposed and 72 chromium-exposed workers from six Shanghai electroplating plants based on airborne and urinary nickel and chromium measurements. Three industrial hygienists and three occupational physicians independently ranked the exposure intensity of each metal on an ordinal scale (1-4) for each worker's job in two rounds: the first round was based on responses to an occupational history questionnaire and the second round also included responses to an electroplating industry-specific questionnaire. The Spearman correlation (r(s)) was used to compare each rating's validity to its corresponding subject-specific arithmetic mean of four airborne or four urinary measurements. Reliability was moderately high (weighted kappa range=0.60-0.64). Validity was poor to moderate (r(s)=-0.37-0.46) for both airborne and urinary concentrations of both metals. For airborne nickel concentrations, validity differed by plant. For dichotomized metrics, sensitivity and specificity were higher based on urinary measurements (47-78%) than airborne measurements (16-50%). Few patterns were observed by metal, assessment round, or expert type. These results suggest that, for electroplating exposures, experts can achieve moderately high agreement and (reasonably) distinguish between low and high exposures when reviewing responses to in-depth questionnaires used in population-based case-control studies.

Characterization and assessment of dermal and inhalable nickel exposures in nickel production and primary user industries

The aim of this study was to measure the levels of nickel in the skin contaminant layer of workers involved in specific processes and tasks within the primary nickel production and primary nickel user industries. Dermal exposure samples were collected using moist wipes to recover surface contamination from defined areas of skin. These were analysed for soluble and insoluble nickel species. Personal samples of inhalable dust were also collected to determine the corresponding inhalable nickel exposures. The air samples were analysed for total inhalable dust and then for soluble, sulfidic, metallic, and oxidic nickel species. The workplace surveys were carried out in five different workplaces, including three nickel refineries, a stainless steel plant, and a powder metallurgy plant, all of which were located in Europe. Nickel refinery workers involved with electrolytic nickel recovery processes had soluble dermal nickel exposure of 0.34 microg cm(-2) [geometric mean (GM)] to the hands and forearms. The GM of soluble dermal nickel exposure for workers involved in packing nickel salts (nickel chloride hexahydrate, nickel sulphate hexahydrate, and nickel hydroxycarbonate) was 0.61 microg cm(-2). Refinery workers involved in packing nickel metal powders and end-user powder operatives in magnet production had the highest dermal exposure (GM = 2.59 microg cm(-2) soluble nickel). The hands, forearms, face, and neck of these workers all received greater dermal nickel exposure compared with the other jobs included in this study. The soluble nickel dermal exposures for stainless steel production workers were at or slightly above the limit of detection (0.02 microg cm(-2) soluble nickel). The highest inhalable nickel concentrations were observed for the workers involved in nickel powder packing (GM = 0.77 mg m(-3)), although the soluble component comprised only 2% of the total nickel content. The highest airborne soluble nickel exposures were associated with refineries using electrolytic processes for nickel recovery (GM = 0.04 mg m(-3) total nickel, containing 82% soluble nickel) and those jobs involving contact with soluble nickel compounds (GM = 0.02 mg m(-3) total nickel content, containing 76% soluble nickel). The stainless steel workers were exposed to low concentrations of relatively insoluble airborne nickel species (GM = 0.03 mg m(-3) total nickel, containing 1% soluble nickel). A statistically significant correlation was observed between dermal exposures for all anatomical areas across all tasks. In addition, the dermal and inhalable (total) nickel exposures were similarly associated. Overall, dermal exposures to nickel, nickel compounds, and nickel alloys were relatively low. However, exposures were highly variable, which can be explained by the inconsistent use of personal protective equipment, varying working practices, and different standards of automation and engineering controls within each exposure category.

Serum and urine nickel in nickel-sensitized women: effects of oral challenge with the metal

15 women with a positive patch test only to nickel (Ni) and without atopy and 10 control women were selected for the study. Blood and urine specimens were collected with a standard procedure either before (at 8 a.m.) or 4 and 24 h after the ingestion of 10 mg of Ni (as Ni sulfate). 7 of the Ni-sensitized patients showed a flare-up of eczema and/or urticaria during the test, while the other women were non-symptomatic. Serum and urine Ni of controls and Ni-sensitized women did not significantly differ. Serum and urine Ni levels determined before the oral Ni challenge were in the range of reference values recently reported by other authors (0.2-2.0 micrograms/l of serum or urine). Ni was greatly augmented in urine and serum 4 h after the challenge (25th-75th percentiles: 43-264 micrograms/l urine Ni and 15-52 micrograms/l serum Ni). 24 h after Ni ingestion, urine Ni was 41-153 micrograms/l and serum Ni 4-17 micrograms/l. Our study confirms a previous investigation showing similar levels of serum and urine Ni following ingestion of the metal in control and Ni-sensitized women without atopy.