Testosterone

Additional information on environmental fate and behaviour

Administrative data

Endpoint:

additional information on environmental fate and behaviour

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted according to well documented methods.

Data source

Reference

Reference Type:

publication

Title:

Degradation Kinetics of Testosterone by Manure-Borne Bacteria: Influence of Temperature, pH, Glucose Amendments, and Dissolved Oxygen

Author:

Yun-Ya Yang, Thomas Borch,* Robert B. Young, Lawrence D. Goodridge, and Jessica G. Davis

Year:

2010

Bibliographic source:

J. Environ. Qual. 39 (2010)

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

Testosterone

EC Number:

200-370-5

EC Name:

Testosterone

Cas Number:

58-22-0

Molecular formula:

C19H28O2

IUPAC Name:

17-hydroxyandrost-4-en-3-one

Applicant's summary and conclusion

Conclusions:

These results indicate that testosterone is rapidly degraded by manure-borne bacteria under a wide range of environmentally relevant conditions.

Executive summary:

Land application of manure may contribute endocrine disrupting compounds (EDCs) such as steroid hormones to the environment. Little attention has been paid to the potential for degradation of steroid hormones by manure-borne bacteria and their degradation kinetics and pathways. In a laboratory study, the potential for biodegradation of testosterone, 17b-estradiol (E2) and progesterone by swine (Sus scrofa) manure-borne bacteria was examined. In addition, the impact of temperature, pH (6, 7, and 7.5), glucose amendments (0, 3, and 22 mmol L–1), and presence of oxygen on testosterone degradation kinetics was determined. Testosterone, 17b-estradiol and progesterone were biodegraded within 25 h of reaction initiation under aerobic conditions. The degradation of testosterone followed pseudo first-order and zero-order reaction kinetics under aerobic and anaerobic conditions, respectively, in tryptic soy broth (TSB) pre-enriched systems. The half-life (t1/2) for the degradation of testosterone under anaerobic conditions was six times longer than aerobic conditions. Testosterone degradation was found to significantly increase (~ 17%) when incubated at 37°C vs. 22°C. The impact of pH (t1/2 ranged from 4.4–4.9 h) and glucose amendments (t1/2 ranged from 4.6–5.1 h) on the testosterone degradation rate were found to be small. Testosterone was transformed to dehydrotestosterone (DHT) (major degradation product), androstenedione (AD), and androstadienedione (ADD) under aerobic conditions as revealed by liquid chromatography-time-of-flight mass spectrometry (LC/TOF-MS). These results indicate that testosterone is rapidly degraded by manure-borne bacteria under a wide range of environmentally relevant conditions.