Aurel J. Acher, Cathleen J. Hapeman, Daniel R. Shelton, Mark T. Muldoon, William R. Lusby, Adi Avni, and Rolland Waters.
Comparison of Formation and Biodegradation of Bromacil Oxidation Products in Aqueous Solutions, Journal of Agricultural and Food Chemistry 1994 42 (9), 2040-2047From http://europepmc.org/abstract/AGR/IND20496510
(no abstract in original publication)
A comparative study of several oxidation methods of aqueous bromacil (I) solutions was conducted as part of a series of investigations concerning the chemical and biological remediation of pesticide-laden wastes. Ozonation (A), UV photolysis at 254 nm (B), and sensitized sunlight photodegradation (C) methods were examined. The A products were isolated and their structures elucidated by mass spectroscopy, various 13C and 1H NMR techniques, and other chemical methods. Three main A products were identified: 3-sec-butyl-5-acetyl-5-hydroxyhydantoin (II, ca. 5%), 3-sec-butylparabanic acid (III, ca. 20%), and 3-sec-butyl-5,5-dibromo-6-methyl-6-hydroxyuracil (IV, ca. 5%), which was also synthesized via hydroxybromination of bromacil; a fourth product (VII) was obtained in minute amount but was not identified. The aqueous solutions of IV are unstable and its decomposition led to re-formation of I. The main products found in B [(3-sec-butyl-6-methyluracil (V) and a dimer compound, VI] and C (II and VI) were similar to those described previously. The biodegradation assays of I, A, B, and C solutions were investigated using activated sludge, a pure culture of Klebsiella terragena (DRS-I), or soil; they indicated that the B and C solutions were more biodegradable than A solutions, while the parent material (I) was nonbiodegradable. A phytotoxicity bioassay, using Nicotiana tabacum seedlings, showed complete detoxification of the B and C solutions but only partial detoxification of the A and IV solutions. An attempt has been made to evaluate the most suitable method of degradation of solutions of I.