###### Abstract  
This study analyzed concentrations of 17$-estradiol (E2), estrone (E1), estriol (E3), 17$-ethylestradiol (EE2), diethylstilbestrol (DES), 17$-estradiol-3-sulfate (E2-3S), estrone-3-sulfate (E1-3S), 17$-estradiol-3-glucuron (E2-3G), and estrone-3-glucuron (E1-3G) in river water, received from intensive feedlot operations wastewater in WuLo Creek, Taiwan. Moreover, the estrogen degradation in situ was analyzed. The average concentrations were 54.15 \(\pm\) 31.42, 9.71 \(\pm\) 6.42 and 3.55 \(\pm\) 2.41 ng/L for E1, E2 and E3, respectively. The concentrations and order were similar to the polluted river and higher than most rivers' concentrations. The conjugated estrogen concentrations ranged from ND to 13.2 ng/L (E1-3S), ND to 10.4 ng/L (E2-3S), ND to 10.0 ng/L (E1-3G), and ND to 3.6 ng/L (E2-3G), and the detection rates were 76%, 71%, 56%, and 15%, respectively. In the present study, the high detection rates of conjugate estrogen were more elevated than the water receiving STP effluent, suggesting that the source was the river water close to the animal wastewater discharge. In the degradation test, the DES concentrations slightly declined after 24 h, but E1-3G did not significantly change over time (\(p\) > 0.05). The degradation of free estrogen occurred during the first 12 h period, and residual concentration was not further decreased after 24 h. In the environment, E1 had higher concentrations than E2 and E3, suggesting that E1 was more resistant to degradation than E2 and E3 at low concentrations. However, the degradation test in the present study suggested that E1 rapidly degraded at high ambient concentrations due to the high degradation constant. free estrogen; conjugate estrogen; estrogen degradation; first-order kinetic constants; half-life; environmental pollution +
Footnote †: journal:  
Accepted: 21 November 2022  
Published: 23 November 2022  
**Published: 23 November 2022**  
animal feedlot operation discharge compared with the water bodies affected by human discharge [1; 24; 25]. An intensive animal feedlot dramatically increases the discharge estrogen concentration. Previous studies suggested that animal estrogens are ubiquitous in the environment, resulting from manure input or uncontrolled natural sources [12; 26]. Animal excrete contains many estrogen compounds that promote estrogenic potency in the receiving water environment, which has a high variation proportion of conjugated estrogen from 3% to 95% [12; 27; 28; 29; 30] and about 73% to 83% of estrogen estimated from animal excrement into an environment [25; 31]. Remarkably, the presence of estrogen in rivers endangers ecological safety, so more information on the estrogen fate in rivers is needed. Hence, estrogen in animal discharge requires further investigation of the fate in the aquatic environment. Degradation is one of the main factors affecting estrogen's fate in an aquatic environment. Degradation half-life is used to measure the stability and persistence of estrogen substances in the environment. Some previous studies have focused on laboratory addition experiments to know which microorganisms contributed to the degradation of estrogens in the aquatic environment [14; 32]. Although estrogen can be degraded in the laboratory, the studies used a high concentration addition of a single estrogen in river water or a few species of estrogens [33; 34]. Previous studies showed the degradation half-life of E1 and E2 was between 0.1-11 and 0.2-9 days, respectively [8; 33]. [PERSON] et al. [21] pointed out the half-life of Glu-type estrogen was 0.4 h in sludge and increases to 2 days in the river water. With the spiking experiment, the initial 17\(\beta\)-estradiol-3-sulfate (E2-3S) concentration was from 40 to 4000 ng/L, and the half-life was from 2.7 to 86.6 h [35]. Those methods still cannot reflect river water's actual degradation because of the matrix's influence and the existence of reversible reactions of various compounds [4; 33; 34; 35].