Occupational exposure to inorganic lead in a printing plant in Mexico City

OBJECTIVE: To describe occupational lead exposure and its biological indicators in workers in a printing company. MATERIAL AND METHODS: An epidemiological and industrial hygiene research was undertaken. Lead was measured in the air of work environment and on the hands of the participants; additionally, subjects underwent a venous blood samples for the determination of whole blood lead by atomic absorption spectrophotometry; and a bone lead measurement using a spot-source 109Cd K-X-ray fluorescence instrument. Also, a standardized questionnaire was applied. We obtained information on demographic and life styles factors, work history, type of work, position and activity within the company. RESULTS: Of the 209 workers, 117 agreed to participate and 90 (83.3% males and 16.7% females) completed all phases of the study. The average lead concentrations were: in air samples, of 0.94 microgram/m3; in hands before washing, of 6,802 micrograms/m2; in hands after washing, of 194 micrograms/m2; in whole blood, of 12.3 micrograms/dl; and in tibia and fibula, of 25.9 and 43.3 micrograms Pb/g of bone mineral, respectively. Important variations in these measurements were observed according to the workers post. CONCLUSIONS: Worldwide, lead exposure levels have been used to evaluate acute exposures being in the workplace. The higher lead levels find in the bone of the workers in this study are similar to other occupational studies in the United States of America and suggest that the accumulated metal in bone may be an important endogenous exposure source, and here its measurement importance. However in developing countries because its high costs per application, the measurements in bone lead become limited to epidemiological research, although not as an instrument for occupational epidemiological surveillance. In Mexico, there are no reliable studies of occupational lead exposure, which would allow the establishment of both, maximum permissible ambient and biological levels. This study is intended to contribute to blood lead standard setting, which is being discussed in Mexico.