Biomonitoring of Metal Exposure During Additive Manufacturing (3D Printing).

BACKGROUND: Additive manufacturing (AM) is a rapidly expanding new technology involving challenges to occupational health. Here, metal exposure in an AM facility with large-scale metallic component production was investigated during two consecutive years with preventive actions in between. METHODS: Gravimetric analyzes measured airborne particle concentrations, and filters were analyzed for metal content. In addition, concentrations of airborne particles <300 nm were investigated. Particles from recycled powder were characterized. Biomonitoring of urine and dermal contamination among AM operators, office personnel, and welders was performed. RESULTS: Total and inhalable dust levels were almost all below occupational exposure limits, but inductively coupled plasma mass spectrometry showed that AM operators had a significant increase in cobalt exposure compared with welders. Airborne particle concentrations (<300 nm) showed transient peaks in the AM facility but were lower than those of the welding facility. Particle characterization of recycled powder showed fragmentation and condensates enriched in volatile metals. Biomonitoring showed a nonsignificant increase in the level of metals in urine in AM operators. Dermal cobalt and a trend for increasing urine metals during Workweek Year 1, but not in Year 2, indicated reduced exposure after preventive actions. CONCLUSION: Gravimetric analyses showed low total and inhalable dust exposure in AM operators. However, transient emission of smaller particles constitutes exposure risks. Preventive actions implemented by the company reduced the workers' metal exposure despite unchanged emissions of particles, indicating a need for careful design and regulation of the AM environments. It also emphasizes the need for relevant exposure markers and biomonitoring of health risks.

Nephrotoxicity of uranium in drinking water from private drilled wells.

OBJECTIVES: To investigate the association between uranium in drinking water from drilled wells and aspects of kidney function measured by sensitive urine tests. METHODS: Three hundred and one of 398 eligible subjects (75.6%) aged 18-74 years with daily drinking water supplies from private drilled wells located in uranium-rich bedrock (exposed group) volunteered to participate along with 153 of 271 local controls (56.4%) who used municipal water. Participants responded to a questionnaire on their water consumption and general health, and provided a morning urine sample and drinking water for analysis. RESULTS: The uranium content of well water samples (n=153) varied considerably (range <0.20-470 microg/l, median 6.7 microg/l, 5% >100 microg/l), while uranium levels in all samples of municipal water (n=14) were below the limit of quantification (0.2 microg/l). Urinary levels of uranium were more than eight times higher in exposed subjects than in controls (geometric means 38 and 4.3 ng/l, respectively; p<0.001), but their mean urine lead levels were not significantly different. There was a strong curvilinear correlation between uranium in drinking water and in urine (r2=0.66). Levels of albumin, beta(2)-microglobulin, protein HC as well as kappa and lambda immunoglobulin chains in urine from exposed and controls were similar. The N-acetyl-beta-d-glucosaminidase (NAG) activity was significantly lower in the exposed group vs. controls, possibly secondary to differential storage duration of samples from the two groups. Even in regression models adjusting for gender, age and smoking no association of uranium in water and the kidney function parameters was observed. Using uranium in urine in the entire study group as a marker of exposure, however, a tendency of exposure-related increases of beta(2)-microglobulin, protein HC and kappa chains were noted. This tendency was enhanced after exclusion of subjects with diabetes mellitus from the analysis. CONCLUSIONS: Uranium levels in urine were strongly correlated to levels in drinking water from drilled wells. There were no clear signs of nephrotoxicity from uranium in drinking water at levels recorded in this study, but some indications of an effect were observed using uranium in urine as a measure of overall uranium exposure. The clinical relevance of these findings remains unclear.

Lead exposure from tourist earthenware: a pilot survey.

Lead from glazed earthenware used for food storage is a well-known health hazard sporadically causing lead intoxication and may be a source of disseminating lead exposure in specific population groups. To obtain a contemporary scope of the problem a pilot survey was conducted in a random sample of 2000 households with Swedish charter tourists to Greece in 2003. Response was obtained from 214 (10.7%). From these households blood samples were obtained from 33 potentially lead exposed subjects and 33 controls (participation rate among selected participants of each category was 66% and 33%, respectively). No statistically significant difference in mean blood lead was found between groups (arithmetic mean 0.13 and 0.10micromol/l for exposed and controls, respectively; p>0.05), but increased lead levels for two exposed subjects (1.0 and 0.77micromol/l) were associated with their Hellenic earthenware (tea mugs). This pilot survey, probably the first epidemiological study of the current problem, did not indicate that earthenware purchased in Greece by Swedish tourists and used for food storage is a widespread source of lead, but limitations with regard to statistical power preclude definite conclusions.

Occupational molybdenum exposure and a gouty electrician.

BACKGROUND: Molybdenum is an essential trace element and a component of xanthine oxidase, which catalyses the formation of urate. The toxicity of molybdenum in humans is considered to be low, but hyperuricaemia and gout-like symptoms have been observed sporadically. METHODS: A case of hyperuricaemia and gouty arthritis in a young man with occupational exposure to molybdenum is described. Improvement during an exposure-free period was followed by a relapse after a reconstruction designed to quantify his molybdenum exposure. CONCLUSION: This case seems to represent the first observation of gout associated with occupational molybdenum exposure, but the association might also be entirely circumstantial.