| The Fate of Trenbolone Acetate and Melengestrol Acetate after Application as Growth Promoters in Cattle: Environmental Studies Bettina Schiffer,1 Andreas Daxenberger,1 Karsten Meyer,2 and Heinrich H.D. Meyer1 1Institute of Physiology and 2Institute of Animal Hygiene, TU München-Weihenstephan, Freising-Weihenstephan, Germany
Abstract
The steroids trenbolone acetate (TbA) and melengestrol acetate (MGA) are licensed as growth promoters for farm animals in several meat-exporting countries. Although many studies have explored their safety for both animals and consumers, little is known about their fate after excretion by the animal. Our study aimed to determine the residues and degradation of trenbolone and MGA in solid dung, liquid manure, and soil. In animal experiments lasting 8 weeks, cattle were treated with TbA and MGA. Solid dung and, in case of trenbolone, liquid manure were collected and spread on maize fields after 4.5 and 5.5 months of storage, respectively. Determination of the hormone residues in all samples included extraction, clean-up (solid-phase extraction) , separation of metabolites and interfering substances by HPLC (RP-18) , and quantification by sensitive enzyme immunoassay. Procedures were validated by mass spectrometry (MS) methods. During storage of liquid manure the level of trenbolone decreased from 1,700 to 1,100 pg/g (17 -isomer) , corresponding to a half-life of 267 days. Before storage, the concentrations in the dung hill ranged from 5 to 75 ng/g TbOH and from 0.3 to 8 ng/g MGA. After storage, levels up to 10 ng/g trenbolone, and 6 ng/g MGA were detected. In the soil samples trenbolone was traceable up to 8 weeks after fertilization, and MGA was detected even until the end of the cultivation period. The results show that these substances should be investigated further concerning their potential endocrine-disrupting activity in agricultural ecosystems. Key words: degradation, dung, growth promoter, manure, melengestrol acetate, soil, trenbolone. Environ Health Perspect 109:1145-1151(2001) . [Online 2 November 2001] http://ehpnet1.niehs.nih.gov/docs/2001/109p1145-1151schiffer/ abstract.html Address correspondence to B. Schiffer, Institute of Physiology, TU München-Weihenstephan, Weihenstephaner Berg 3, D-85354 Freising-Weihenstephan, Germany. Telephone: + 49 8161 715546. Fax: + 49 8161 714204. E-mail: schiffer@weihenstephan.de These studies were financially supported by the European Union. Received 28 December 2000 ; accepted 19 April 2001.
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