Detection And Occurrence Of Thyroid Hormones In Sewage And Surface Water

As endocrine disruptor compounds,thyroid hormones have attached more and more attention.Studies have found that Thyroxine(T4)and 3,3?,5-triiodo-thyronine(T3)had persistence,high biological activity and bioconcentration,and were considered as potential wastewater pollutants.However,due to the lack of a sensitive method to detecting various trace of thyroid hormones in complex environmental matrices,their occurrences,concentrations,distribution characteristics and environmental behaviors in the environment are still unclear.In this study,a highly sensitive method(Derivatization combined with Ultra-high performance liquid chromatography tandem mass spectrometry)for simultaneously and specifically detecting 10 thyroid hormones in complex environmental matrices was established and applied to the analysis of thyroid hormones in sewage treatment plants and surface water around Beijing.In this study,3-iodo-L-tyrosine(MIT),3,5-diiodo-L-tyrosine(DIT),Thyronine(T0),3-iodo-Lthyronine(T1),3?-iodo-L-thyronine(r T1),3,3?-diiodo-thyronine(T2),3,5-diiodo-L-thyronine(r T2),3,3?,5?-triiodo-thyronine(r T3),T3 and T4 were selected as research subjects.Because the derivatization reaction greatly improved the sensitivity of instrument detection,200 ?L water samples were directly derived after simple filtration.10 thyroid hormones in 4 m L water samples were concentrated by ultra-low temperature freeze-drying.Vortex oscillation extraction with methanol/acetone(1:1,v/v)was used to extract thyroid hormones in the activated sludge.The absolute recoveries were 62-120%(water)and 48-83%(sludge),the limit of detection was 0.01-0.72 ng/L in water samples and 0.03-0.09 ng/g dw in sludge samples.The concentrations of thyroid hormones in the influent of the sewage treatment plant were 2.0-11 ng/L,and the pollution level of T0 were highest,followed by DIT and MIT.Although the concentrations of other thyroid hormones such as T4 and T3 were low,they may have higher biological activity.The A/O technology showed good removal(81-100%)for other 8 thyroid hormones except T3 and r T3,and the removal efficiencies of T3 and r T3 were only 46% and 14%.Based on mass balance calculation,biodegradation,especially aerobic degradation was the main removal mechanism for some thyroid hormones.The pollution of thyroid hormones in Beijing surface water was ubiquitous.All 10 compounds were detected and the maximum environmental concentration was up to 11 ng/L.The pollution of MIT,DIT and T0 was the most serious,followed by T4 and T3 with high biological activity,which might pose potential high ecological risks to aquatic organisms of Wenyu River.Among the four rivers,the pollution of Wenyu River was the most serious,while the other tributaries including Ba River,Qing River and Tonghui River were similar and the pollution of discharging sites found downstream of the tributaries was quite serious.In addition,the results suggested that the effluent was not the main source of pollution of thyroid hormone in this basin by comparison of the occurrences and concentrations of thyroid hormones in the river,outlets of sewage treatment plant and the downstream sampling sites.