Hair and urine analysis for biomonitoring of environmental and occupational exposure to metals

Background Non-invasive samples of human biological matrices present ethical and practical advantages for investigating human exposure to hazardous contaminants. In particular, element concentrations in urine and hair are widely recognized as bioindicators of short- and long-term exposure, respectively. Still, analytical challenges and difficulties in interpreting the results limit their application in biomonitoring. In this work, we investigated the potential for using hair and urine samples to measure internal exposure to metals in two populations with different occupational exposure conditions (ceramics company and foundry) and in the control population. Materials and methods Urine samples were collected in 100 mL polypropylene bottles and stored at -20 °C until analysis. Hair was obtained with clean stainless steel scissors and stored at room temperature until analysis. The study was approved by the CNR Ethics Committee. Before the study, informed consent was signed by all study participants. We collected information on occupation, lifestyle habits and food intake by questionnaire. The treatment of hair and urine samples was performed using previously validated protocols. Determination of elemental content was performed by ICP-MS. Results In general, females had higher metal levels in both biological matrices. Smoking was directly associated with Cd, Ce and Rb levels in urine and Ce, Fe, La, Na and Si in hair. Urinary Pb and Co, Mg, Pb, Si and Zr levels in hair of ceramic workers are the highest. Urinary Cr concentration is higher in the worker population than in the control. Finally, Fe in hair of foundry workers presents the highest values. Conclusions The workplace man may be exposed to different levels of known and unknown chemicals, apart from environmental exposure. Overall, the study confirmed that the work activities considered are associated with increased absorption of some metals, particularly Cr, and Pb in urine and Co, Pb, Si, and Zr in the hair of ceramic workers. This biomonitoring study has confirmed the potential usefulness of multiple matrix measurements to evaluate the exposure to metals among workers. The results of this work constitute the first exposure data of workers of ceramic and foundry companies.