Zinc exposure in Chinese foundry workers

Abstract

Background: Inhalational exposure to zinc oxide fumes is associated with metal fume fever, a self‐limited but very uncomfortable condition closely resembling influenza. Very little is known regarding the toxicokinetics of inhaled zinc, making the interpretation of zinc measurements in serum and urine problematic. Methods: Twenty workers in a zinc foundry in Baiyin, Peoples' Republic of China, were investigated with serial examinations by a physician, chest radiographs, and spirometry. Exposure assessment consisted of the measurement of zinc in serum, urine, and personal air samples. Results: No cases of metal fume fever were observed during the study period despite exposures to as high as 36.3 mg/m3 over less than 4 hr. In addition, no radiographic or functional changes were noted. Serum zinc levels of all workers were within the reference range and did not correlate with external exposure measurements. However, elevations were noted in urinary zinc levels, which showed a significant association (Spearman's correlation coefficient = 0.47, P = 0.04) between exposure to zinc and urine zinc. Conclusions: These results provide exposure measurements for zinc at which workers demonstrate tolerance to the development of metal fume fever. Furthermore, they suggest that urine may be the preferred biological medium for the assessment of zinc exposure. Am. J. Ind. Med. 35:574–580, 1999. © 1999 Wiley‐Liss, Inc.

Zinc exposure for female workers in a galvanizing plant in Northern Italy

“…did not provide estimates of the relationship between zinc exposure levels and the levels of zinc in biological fluids but collectively confirmed that zinc was absorbed following inhalation exposure [14,[29][30][31]. However this data should be interpreted cautiously for several reasons.…”

“…As the composition of the plating bath depends on the processes Primary pulmonary involvement is characterized by reduced lung volumes and a decreased diffusing capacity of carbon monoxide [11][12][13]. Signs/symptoms usually occur within 4-8 h after exposure to Zn/ZnO fumes and persist for h. An increased tolerance develops within repeated exposures but it is lost after a brief period without exposure: as MFF symptoms are most commonly reported at the beginning of the working week and after holidays, it is otherwise called "Monday morning syndrome" [14]. Zinc exposure in the general population occurs primarily through ingestion, with an average intake of 5.2-16.2 mg/day.…”

“…Toxicokinetics of inhaled zinc still remains largely undefined. Early studies on animals exposed to airborne ZnO found increased zinc concentration in the gallbladder, kidney and pancreas [28] whereas elevated levels of zinc had been reported in the urine of workers exposed to fumes containing ZnO [14,29]. Unfortunately, available studies employed, particulate and vapor emissions are also quite variable.…”

Toxicological Profile for Zinc

“…This heating results in the formation of fresh zinc oxide particles (0.2-1.0 µm), which may subsequently be inhaled. Inhalation of zinc oxide particles and fumes by workers can result in metal fume fever (Martin et al 1999). Inhalation was reported to be the most probable route of exposure to zinc for 26 lead smelter workers found to have significantly (p<0.01) elevated blood plasma levels of zinc.…”

“…Mean plasma zinc concentrations were 12.9 mmol/L (range, 9.8-16.7) for the workers versus 10.9 mmol/L (range, 8.1-14.6) for a nonlead-exposed control group (Vasikaran et al 1992). Twenty workers in a zinc foundry in Baiyin, China were investigated for exposure to zinc oxide fumes (Martin et al 1999). Eighteen of the workers had worked at the foundry since its opening 6 years earlier.…”