RELATIONSHIPS BETWEEN BIOMARKERS OF EXPOSURE AND NEUROLOGICAL EFFECTSIN A GROUP OF WORKERS EXPOSED TO ACRYLAMIDE

A study was performed among 41 workers heavily exposed to a mixture of acrylamide and acrylonitrile in the city of Xinxiang, Henan province, People's Republic of China. The workers underwent a complete medical and neurological examination and provided blood and urine for the dete rmination of several biomarkers of exposure. Among the exposed workers , signs and symptoms indicating peripheral neuropathy were found with statistically significant increased frequencies compared to a group of controls from the same city. Based on neuropathic signs and symptoms and quantifiable indicators of peripheral nervous dysfunction, such as vibration thresholds and electroneuromyography measurements, a neurot oxicity index (NIn) specific for acrylamide-induced peripheral neuropa thy was designed. The NIn, which adequately predicted the clinical dia gnosis of peripheral neuropathy, was significantly correlated with the levels of mercapturic acids in 24-hr urine, hemoglobin adducts of acr ylamide, accumulated in vivo doses of acrylamide, employment time, and vibration sensitivity. The NIn was correlated also with hemoglobin ad ducts of acrylonitrile, which was explained primarily by a correlation between acrylamide and acrylonitrile exposure in this workshop. Howev er, it was not significantly correlated with momentary measures of exp osure such as concentrations of acrylamide in the air or in the plasma of exposed workers. This study is the first in which adduct monitorin g has been applied to the same group of individuals in which adverse h ealth effects have been observed. The results seem to indicate that he moglobin adducts are useful as predictors of acrylamide-induced periph eral neuropathy and that measurements of vibration thresholds are usef ul for identifying early neurotoxic effects in workplaces with hazardo us exposures to acrylamide. (C) 1994 Academic Press, Inc.