OBJECTIVETo investigate the incidence of malignant tumors among fluoride-exposed workers in aluminum industry.

METHODSSampling points were set in the working positions at different radii around an workshop for treating the waste gas from aluminum electrolysis, and the concentrations of fluoride ions, aluminum, and benzo[a]pyrene (B[a]P) in air were measured by electrode method, atomic absorption spectrophotometry, and high performance liquid chromatography, respectively. The incidence of tumors among the workers in the aluminum plant from 1995 to 2009 was investigated by questionnaires and medical records and then statistically analyzed.

RESULTSThere was a negative correlation between the concentrations of fluoride and aluminum and the radius around the fluoride source at each sampling point. B[a]P was not detected at each sampling point. The crude incidence rate of tumors among factory workers was 117.95/100 000 (standardized rate = 58.81/100 000); the standardized incidence rate of tumors was higher in female workers than in male workers (male-to-female ratio = 1:2.64). The peak age of onset of tumors was 40 ∼ 49 years. The most and second most common tumors were liver cancer and lung cancer in male workers and breast cancer and lung cancer in female workers. Compared with the unexposed population in the city where the aluminum plant was located, the female fluoride-exposed workers had an increased tumor incidence, 2.14 times that of the city's average level, and the fluoride-exposed workers had a younger age of onset of tumors and approximately the same types of tumors.

CONCLUSIONFluoride exposure may lead to an increasing trend in tumor incidence among female workers in aluminum industry.