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The health effect of lead exposure has frequently been studied in lead-acid battery manufacture. But relatively few studies focused on the effect of sulfuric acid, which is also used widely in this process. In addition to acute effects such as eye irritation and dental erosion, exposure to sulfuric acid may induce respiratory cancers, including laryngeal cancer and lung cancer, but there was no similar evidence for nasal cancer. International Agency for Research on Cancer (IARC) recommended exposure to strong inorganic acid mists including sulfuric acid as group 1 human carcinogen in 1992. However, these studies were in lack of accurate or appropriate exposure measurements. In 1995, three cases of nasopharyngeal cancer were reported in a tele-communication company. It was suspected that they were related to exposure to sulfuric acid mists. The objective of this study was to determine the air concentration and particle sizes of sulfuric acid in lead acid battery factories.
This study selected three lead-acid battery plants, with one employed less than 30 workers, another employed 30-100, while the last one employed more than 100. We used three sampling methods including silica gel tube, 37-mm filter cassette, and Andersen eight-stage impactor to collect airborne sulfuric acids, which were later analyzed by ionic chromatography with an IONPAC AS4A Analytic column (Dionex Corp., Sunnyvale, CA, U.S.A.). The result showed that the silica gel tube had the best sampling efficiency. Concentrations of sulfuric acid in silica gel tube were 15.5 to 394.4 mg/m3 in Factory A, 11.1 to 64.2 mg/m3 in Factory B, and 30.9 to 99.8 mg/m3 in Factory C. Concentrations in the forming and cleaning operations were higher than other areas and their particle sizes were in general bigger (MMAD=6-11 mm). The result of this preliminary exposure assessment may help outline the epidemiological study for sulfuric acid related effects in the future.
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