Abstract: The GC/MS detection was used to investigate the environmental hormone (PAEs) contents of phthalate esters in the ensilage and concentrated feed of milk cows. The results showed that the PAEs was completely extracted from feed with acetonitrile and ultrasonic in 30 min. The recovery coefficients were from 85.42% to 104.92%, and relative standard deriations (RSD) were 1.12% to 4.97%, these results indicated that the method had high recoverity, low variation of RSD and effective and accurate to detect of PAEs in feed. The contents of dibutyl phthalate (DnBP) and phthalate (2-ethy1) hexy1(DEHP) were relatively high in the feed samples. In the green storage feed, not only the individual data but also the total amount of the PAEs was significantly higher than the data of concentrated feed. It concluded that the arable soil has been polluted by the PAEs which came from the agricultural plastic films. What follows next, the crops which were as feed to be used were polluted through the farmland affected by the PAEs, and then, the feed was contamintated. People should pay more attention to this process of pollution and it is necessary to further study.

Key words: feed; phthalic acid ester; environmental hormone