Direct Photodegradation of Androstenedione and Testosterone in Natural Sunlight: Inhibition by Dissolved Organic Matter and Reduction of Endocrine Disrupting Potential

• Published in: Environmental science & technology Vol. 47; no. 15; pp. 8416 - 8424
• Main Authors: Young, Robert B, Latch, Douglas E, Mawhinney, Douglas B, Nguyen, Thanh-Hoa, Davis, Jasmine C. C, Borch, Thomas
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 06.08.2013
• Subjects: androstenedione; Androstenedione - chemistry; Applied sciences; Aqueous solutions; Comparative studies; Continental surface waters; dissolved organic matter; Earth sciences; Earth, ocean, space; Endocrine disruptors; Endocrine Disruptors - chemistry; Endocrine Disruptors - pharmacology; Engineering and environment geology. Geothermics; Exact sciences and technology; half life; Hormones; Kinetics; latitude; Natural water pollution; Nevada; Organic chemicals; Organic Chemicals - chemistry; Oxidation-Reduction; Photochemical Processes; Photochemistry; Photodegradation; photolysis; Pollution; Pollution, environment geology; Quenching; risk reduction; screening; Seasons; solar radiation; Solubility; spring; steroid hormones; Steroids; summer; Sunlight; surface water; testosterone; Testosterone - chemistry; Water treatment and pollution; United States > US; Henderson Nevada; USA; Nevada; Androgen; Pollutant behavior; Endocrine disruptor; Biological activity; Testosterone; Dissolved organic matter; Selfpurification; Surface water; Reaction inhibition; Water pollution; Androstenedione; Sex steroid hormone; Solar radiation; Organic compounds; Photochemical degradation
• ISSN: 0013-936X; 1520-5851; 1520-5851
• DOI: 10.1021/es401689j

In surface waters, two of the most commonly observed androgenic steroid hormones are androstenedione (AD) and testosterone (T). This study compares the photodegradation of dilute (<10 μg L–1) aqueous solutions of AD and T in natural sunlight, and evaluates the endocrine-disrupting potential of the resulting solutions. This study also examines the effect of dissolved organic matter (DOM) on AD photodegradation. During spring and summer at Henderson, NV, USA (latitude 36.04°N), AD and T underwent direct photodegradation, with half-lives ranging from 3.7 to 10.8 h. In three model DOM solutions, AD’s half-life increased by 11% to 35%. Using screening factors to eliminate DOM’s inner filter effect, quantum yield calculations suggested that light screening was primarily responsible for AD’s increased half-life, and that physical quenching further inhibited AD’s photodegradation in two out of three DOM solutions. In vitro androgenic activity of the AD and T solutions decreased approximately as fast as AD and T were removed, suggesting that solar photodegradation reduces the risk of endocrine disruption in surface waters impacted by AD or T, subject to continuing inputs. Reduced in vitro androgenic activity appears to be related to steroid ring cleavage and the formation of highly oxidized photoproducts.