Evaluation of the potential toxic effects of industrial chemicals involved in acrylic resin production

Abstract

The toxic effects of monomers of Acrylonitrile (ACN), Methyl methacrylate (MMA) and Styrene in acrylic resin production were evaluated by studying the factory's environment, investigating general physical condition of workers and studying the effects of short and long term exposure to these monomers on hepatic drug metabolizing enzyme system of rat such as aminopyrine demethylase, aniline hydroxylase, dimethylnitrosamine demethylase isozyme system and glutathione conjugated system. MMA was detected at high level (86.25-501.25 mg/m3) at the workplace due to the open system process and inadequate ventilation. Styrene was detected at low level (4.97-26.67 mg/m3) near the closed reactors and the level of styrene can be fluctuated due to a semi-closed system process, however area sampling may not represent the true exposure level since sampling was allowed only when the reactors were closed. Thus, the workers may be exposed to levels higher than those actually detected. For the health effects assessment in workers, 158 workers in 6 factories were subjected to medical examination. Pterygium and abnormal pulmonary function test were major symptoms found in workers, indicating irritation and respiratory tract malfunction. However, blood chemistry values and urinalysis were almost normal. The level of hippuric acid in urine of styrene-exposed workers were high, indicating that the workers were exposed to styrene since styrene was metabolized to hippuric acid. ACN and MMA caused only a slight change in rat liver microsomal mixed function oxidase enzyme system but caused more pronounced glutathione conjugation system. Styrene, on the contrary, greatly enhanced the hepatic microsomal metabolism of aminopyrine, aniline and dimethylnitrosamine, however glutathione conjugation is one of the major detoxification process of this monomer.