Evaluation of preventive and control measures for lead exposure in a South African lead-acid battery recycling smelter.

摘要

In South Africa, new lead regulations released in February 2002 served as motivation for a cross-sectional study investigating the effectiveness of preventive and control measures implemented in a lead smelter that recycles lead-acid batteries. Twenty-two workers were observed and interviewed. Structured questionnaires were used to gather workers' personal information, perception about their work environment, health risks, and work practices. Retrospective data from air monitoring and medical surveillance programs were obtained from the plant's records. The smelter implemented a number of control measures for lead exposure, including engineering controls, administrative controls, and, as a last resort, personal protective equipment. Engineering controls were rated the best control measure and included local exhaust ventilation systems and wet methods. Positive pressure systems were used in the offices and laboratory. The local exhaust ventilation system was rated the best engineering control measure. Although control measures were used, areas such as smelting and refinery had average lead in air levels above 0.15 mg/m(3), the occupational exposure limit for lead. This was a concern especially with regard to the smelting area because those workers had the second highest mean blood lead levels; workers in the battery breaking area had the highest. Regular use of personal protective equipment by some workers in the "lead exposure zones" was not observed. Although the mean blood lead levels had been below 40 micro g/dL for more than 90% of the workers since 2001, more than 70% of workers reported concerns about their health while working in the smelter. Even though control measures were implemented, they were not adequate because in some areas lead in air exceeded the occupational exposure limit. Therefore, improvement of existing measures and regular monitoring of personal protective equipment use were included in the recommendations given to the smelter.