Occurrence of estrogenic compounds in and removal by a swine farm waste treatment plant

摘要

The total estrogenic activity of the wastewater from a swine farm in Japan was quantitatively characterized, and the compounds responsible for the estrogenic activity were identified and quantified. The wastewater treatment process consisted of a series of an up-flow anaerobic sludge blanket (UASB) and a trickling filter. Samples were collected at each treatment step, and the total estrogenic activity was determined by use of an in vitro gene expression assay (MVLN; MCF-7 human breast cancer cell stably transfected with the pVit-tk-LUC receptor plasmid). Individual estrogenic compounds were identified and quantified using liquid chromatography-mass spectrometry (LC/MS) and liquid chromatography-tandem mass spectrometry (LC/ MS/MS). To further identify the compounds contributing to the estrogenic activity in the wastewater, the sample extracts were fractionated into 12 fractions (fractions 1-12) by HPLC. The rate of removal of estrogenic activity between the effluent and the influent was greater than 97%. The trickling filter removed the majority of the estrogenic activity. The removal rates of specific estrogenic compounds ranged from 44 to 99%. Estrogenic activity was detected mainly in the fractions containing estrone (E1), 17 beta-estradiol (beta E2), 17 alpha-estradiol (alpha E2), estriol (E3), bisphenol A (BPA), and equol (EQO). The ratios of beta E2EQ(C) (beta E2 equivalents derived from chemical analysis) to beta E2-EQ(B) (beta E2 equivalent derived from bioassay) in the 12 fractions collectively were contributed by E1 (17-30%) beta E2 (23-30%) alpha E2 (< 1%), E3 (1-2%), BPA (< 1%), and EQO (2-3%) in the influent and E1 (16-37%) beta E2 (< 1-7%), alpha E2 (< 1%), E3 (< 1-3%), BPA (< 1%), and EQO (< 1%) in the effluent. The compounds responsible for most of the estrogenic activity measured in the bioassay were natural estrogens such as E1 and beta E2.