Biomonitorization of Concentrations of 28 Elements in Serum and Urine among Workers Exposed to Indium Compounds v1

Many studies have documented the abnormal concentrations of metals/metalloids in serum or urine of occupational workers, but no works systematically analysed the concentrations of elements in serum or urine of indium-exposed workers. This study was aimed to assess 28elementsin serum and urinefrom 57individuals with occupational exposureto indium and its compounds. Control subjects were 63 workers without metal exposure. We collected information on occupation and lifestyle habits by questionnaire.Biological sampleswere collected to quantify elements by inductive coupled plasma-mass spectrometer.Air in the breathing zones was drawn at flow rates of 1.5-3 L/min for a sampling period of 6 to 8 h, using a Model BFC-35 pump. The average ambient indiumlevel was 0.078mg/m3.Serum/urineIndium levelswere significantly higher in indium-exposed workers than in controls (P< 0.01).Moreover, serum/urine indium concentrations in the group with 6-14 years and ≥15 years of employment were significantly higher than those with ≤5employment years(P< 0.05). Tenof the other 27 elements/metals measured were higher in serum/urine in indium-exposed workers compared to the controls (aluminum, beryllium, cadmium, cesium, chromium, lithium, manganese, magnesium, molybdenumand vanadium). Zinclevels in serum/urinewere significantly decreased in the indium-exposed workers.Additionally, other elements/metals were higher in one specimen (serum or urine) but lower in the other (Selenium was lower in serum but higher in urine in the indium-exposed workers compared with the controls; Likewise Thallium and Rubidium were higher in serum but lower in urine).Linear regression analyses, revealed significant correlations between serum and urine for indium, aluminum, arsenic, barium, cadmium, cesium, cobalt, selenium, silver, and zinc(P < 0.05). These datassuggest that occupational exposure to indium and its compounds may disturb the homeostasis of trace elements in systemic circulation, indium concentrations in serum or urine appear reflective of workers’ exposure to ambientindium and their years of working, respectively. The serum/urine levels of essential metals are modified by exposure to indium in occupationally exposed workers.