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Fate of estrone in laboratory-scale constructed wetlands

Heldur Hakk, Lawrence Sikora, Francis X.M. Casey
Ecological engineering 2018 v.111 pp. 60-68
Araceae, administered dose, colloids, constructed wetlands, drug residues, environmental fate, estriol, estrone, liquids, mass spectrometry, metabolites, organic matter, pig manure, sediments, steroid hormones, subsurface flow, thin layer chromatography, vegetation, wastewater
A horizontal, subsurface, laboratory-scale constructed wetland (CW) consisting of four cells in series was used to determine the attenuation of the steroid hormone estrone (E1) present in animal wastewater. Liquid swine manure diluted 1:80 with farm pond water and dosed with [¹⁴C]E1 flowed through the series of cells containing floating vegetation (duckweed, family Lemnaceae) and a sand:gravel sediment layer. The aqueous layer within each cell was sampled across time, and at 168h duckweed and sediment were sampled for E1 and/or its metabolites. Control and Blank systems consisted of single cells with no vegetation or no vegetation/sediment, respectively. Only 5% of the dose was detected in the effluent at 168h. With the use of mass spectrometry and thin layer chromatography, it was determined that E1 was metabolized into estriol (E3) and to polar metabolites. The largest compartment for [¹⁴C] was duckweed (42.1% of administered dose) at 168h followed by sediment (17.3%) and the liquid layer (15.1% of the dose). Most of the vegetative removal of E1 occurred in the first cell, and thereafter, sediment:liquid layer interactions governed E1 movement suggesting particle-bound transport on either colloids or dissolved organic matter. Horizontal, subsurface flow CW were able to remove approximately 95% of the influent E1, and demonstrated the importance of vegetative matter in removal of this potent steroid hormone.