ABSTRACT
The aim of the present study was to investigate steroid hormone residues from livestock farms and assess their risks to the surface water of Phayao Lake. These steroid hormones are endocrine-disrupting compounds (EDCs), which can be found in natural and synthetic forms. This research focused on examining the residues of seven steroid hormones (five estrogens and two androgens-estrone (E1), 17α-estradiol (αE2), 17ß-estradiol (ßE2), estriol (E3), 17α-ethinyl estradiol (EE2), testosterone (T), and 17α-methyltestosterone (MT)) from four types of livestock farms around Phayao Lake, Thailand. The samples collected from the livestock farms included feces, soil, and wastewater and were extracted by the solid phase extraction (SPE) technique and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). The risks from the residual steroid hormones were also characterized by estradiol equivalents (EEQs), testosterone equivalents (TEQs), and risk quotients (RQs). The results indicated that most hormone contamination from the farms' livestock was due to the estrogen hormones E1 (1.38-97.10 ng/g), ßE2 (10.08-1366 ng/g), and EE2 (1.50-99.92 ng/g), which originate from the natural excretion and admixture of steroids in feedstock or medicines. Steroid hormones were not detected in the wastewater from cleaning processes on farms with wastewater treatment plants, whereas farms without wastewater treatment plants showed high values of estrogen hormone contamination, with EEQs of 128.8-472.9 ng/L and RQs of 208.3-294.3. However, the analysis of steroid hormone residues in Phayao Lake demonstrated that the residues did not severely affect aquatic organisms (with RQs of 0.002-144.5), and no estrogen or androgen residues were observed in the water treatment plant or tap water.
