A health surveillance case study on workers who manufacture silver nanomaterials.

The levels of exposure and internal doses of nanomaterials are becoming more and more important for estimating the health effects resulting from exposure to nanomaterials. Health surveillance can be used as an indicator of whether exposure is occurring, rather than in determining if levels of exposure are safe. We have conducted a health surveillance study in a workplace which manufactures silver nanomaterials, including the assessment of personal exposure levels to silver nanoparticles, a walk-through evaluation of the manufacturing process and the collection of blood and urine samples from the exposed workers. Two male workers who had worked for 7 years in the business of manufacturing silver nanomaterial were exposed to silver concentrations of 0.35 and 1.35 μg/m(3). The blood and urine levels of silver were 0.034 and 0.0135 μg/dl for blood and 0.043 μg/dl and not detected level for urine. The blood chemistry and haematology data were determined to be within a normal range. Taken together, the health surveillance indicated that the nanomaterial manufacturing workers were exposed to a much lower concentration of silver dust or soluble silver threshold limit values and showed no significant findings on their health status.