Quantitative Analysis And Environmental Behavior Characteristic Of Androgens In Water And Sediment Of The Yangtze Estuary

Environmental androgens are one class of the steroids produced by humans and animals during natural metabolism and the use of drugs,which are then released into the environment.Environmental estrogens have been widely studied,reporting that in water environment,androgens were dominating steroids-both in quantity and concentration.However,the detecting methods for androgens in solid matrix have not been well developed,which are complicated and precisions need to be improved.The occurrence of environmental androgens in China were reported in limited number of cities,and are mostly focused on the distribution in wastewater treatment plants.Therefore,the occurrence of environmental androgens needs to be further investigated.To study the typical androgens released from organisms' natural excretion and livestock,aquaculture cultivation,a pretreatment and analytical method of 11 androgens and progesterone,their precursor in sediments was established in this thesis,which was based on accelerated solvent extraction combined with on-line purification and ultra-high performance liquid chromatography mass spectrometry/mass spectrometry.The developed method was applied to determine the concentrations of target compounds in the Yangtze Estuary to explore their time and spatial distribution pattern as well as environmental behavior characteristics there.Experiments of spiked samples were carried out to optimize the extraction parameters and the results were as follows:five-g neutral alumina with 0%water content was used for online purification;methanol:acetone 1:1(V/V)was selected as the extraction solvent;the optimum extraction temperature and static extraction time was set at 100 ? and 5 minutes respectively;the extraction was carried out twice.The average recoveries for the targets compounds were between 73.7%and 117.3%,relative standard deviations were between 0.1%and 6.8%,limits of detection were between 0.02 ng/g dw(dry weight)and 3.63 ng/g dw,limits of quantitation were between 0.08-12.06 ng/g dw,which can meet the analysis requirements of sediment samples.The analysis results of sediment samples collected from 8 sampling sites of the Yangtze Estuary during 4 seasons in 2016 showed that androstenedione,boldenone,dihydrotestosterone,testosterone and progesterone were detected in all samples,while methyl testosterone,19-nor-4-androstene-3,17-diol and nandrolone were detected in more than half of the samples;the detection results of androsterone,stanozolol aad trenbolone varied in different seasons.Among the 12 target compounds,progesterone was dominant in concentration,whose highest contribution reached 53.0%,followed by androsterone,dihydrotestosterone and androstenedione,whose highest contributions were 29.1%,23.9%and 22.2%respectively.The detected concentrations of remaining compounds were low,all accounting for no more than 6.7%of the total concentration.The total content of androgens reached the peak(99.80 ±0.84 ng/g)at Shidongkou in July;the lowest total content was only 3.97 ±0.03 ng/g at Chaoyang farm in October.The study revealed that the effluents from wastewater treatment plants were the main source of androgens in the sediments of the Yangtze Estuary.The adsorption mechanisms of different androgens in sediments were complex.The total organic carbon content influenced the adsorption of androgen to some degree,but it was not a critical factor.The analysis results of water and sediment samples of 5 sites showed that progesterone and dihydrotestosterone were most likely to be generated in sediment phase,while nandrolone and stanozolol tended to be dispersed in water phase,which were in accordance with their occurrence in water and sediment samples.The logKoc value of androgens is not related to their carbon number and molecular weight,but related to their molecular structure to some extent.Comparing the results of the target compounds in this research with other regions in China,it was shown that the concentration of dihydrotestosterone in the sediment samples of the Yangtze Estuary was much higher than that of the Humen Estuary and Laoyu River,Yunnan.In addition,the concentrations of androsterone,androstenedione,19-nor-4-androstene-3,17-diol,nandrolone and progesterone in sediments at some sampling sites were greater than those in sludge samples from wastewater treatment plants in Guangdong,Beijing,Yunnan and other places.Hence,the pollution of androgens and progesterone in the Yangtze Estuary is serious and needs to be further researched and managed.