Determination of the oestrogenic (uterotrophic) activity of extracts of 'general purpose polystyrene (GPPS)' using immature female rats

In Japan there is growing concern about the possible adverse effects of con sumption of food from styrene containers (mainly those made from polystyren e paper) due to the alleged oestrogenic activity of styrene oligomers (dime rs and trimers), which may migrate into the food. To examine the possible o estrogenic activity of styrene dimers and trimers, extracts were made from 'general purpose polystyrene (GPPS)' and administered orally to immature fe male rats over a 4 day period. Increase of uterus weight (wet and blotted) was used for assessment of possible oestrogenic activity. To establish the sensitivity of the test method, immature rats were treated with diethylstil boestrol (DES), a well-known oestrogenic compound. It was found that treatment of rats with levels of up to 60 mug of styrene dimers and 930 mug of styrene trimers per kilogram body weight per day did not give any statistically significant increase of the uterus weight (wet o r blotted), whereas DES caused statistically significant, dose-related incr eases in uterus weight at: levels as low as 0.89 mug kg(-1) body weight day (-1). It was concluded that, compared with the estimated maximum human dail y intake of styrene trimers of 1 mug kg(-1) body weight day(-1) from polyst yrene food containers, the risk of adverse human health effects with respec t to oestrogenicity may be considered negligible. Copyright (C) 2001 John W iley & Sons, Ltd.