Chemical and analytical support for the assessment of internal exposure to toxic elements in biomonitoring studies

BACKGROUND: Biomonitoring studies are essential for identifying exposure to toxic factors at both the occupational level and in relation to environmental impacts on human health. To improve methods for assessing internal exposure to potentially hazardous elements, it became necessary to expand the list of elements determined using the author-developed technique MUK 4.1.3230-14 from 12 to 17 elements in urine by including the potentially toxic elements beryllium (Be), cobalt (Co), molybdenum (Mo), tin (Sn), and antimony (Sb). AIM: This work aimed to expand the scope of application of MUK 4.1.3230-14 and the working range of determined concentrations of chemical elements in urine to improve approaches to assessing internal exposure to the toxic elements Be, Co, Mo, Sn, and Sb. To achieve this objective, it was necessary to experimentally select measurement conditions using the instrumentation, including selection of an internal standard; optimize sample preparation; establish measurement ranges and calibration relationships for each element; and determine quantitative limits and limits of detection. METHODS: The concentrations of Be, Co, Mo, Sn, and Sb in urine were determined using quadrupole inductively coupled plasma mass spectrometry. Urine samples were directly analyzed after dilution 1:10 (v/v) with a 1% nitric acid solution. Accuracy of the results was confirmed by analysis of certified urine reference materials. Experimental studies confirmed the applicability of these methodological guidelines for measuring mass concentrations of the listed elements in urine with acceptable metrological characteristics. RESULTS: The concentrations of Be, Co, Mo, Sn, and Sb in urine samples from industrial enterprise employees (n = 240; mean age, 43 years) are presented as minimum and maximum values, arithmetic and geometric means, and the 5th, 50th, and 95th percentiles. The P5–P95 ranges in urine were 0.005–0.013 µg/L for Be, 0.026–1.08 µg/L for Co, 2.840–68.390 µg/L for Mo, 0.154–1.040 µg/L for Sn, and 0.016–0.110 µg/L for Sb. CONCLUSION: The results based on the 95th percentile may be used to interpret biomonitoring data related to exposure to potentially hazardous elements under occupational exposure conditions. The 95th percentile values for the study group did not exceed established reference ranges or the results of biomonitoring studies conducted among adult residents of EU countries and the United States.