Preliminary Study On The Typical Environmental Factors Affecting The Activity Of AryS And The Hydrolytic Mechanism Of CE-S

In recent years, the endocrine interference phenomenon has aroused widespreadattention at home and abroad. Steroid estrogens have the hightest activity. Oestrone (E1),17β-Eoestradiol (E2) and17α-ethinyloestradiol (EE2) are the most concerned endocrinedisrupting chemicals regulated by environmental quality standards in the UK.They arepresent in sewage at an ng/L level. Containing excessive aounts of estrogen in sewagewill not only affect the normal growth and development of animals, and also affect thereproductive system through the food chain, such as female sexual precocity,feminization of male bias, reducing sperm quality and quantity, etc.The primary sourcesof estrogens are domestic sewage and farming waste water. The aquatic environmentalso exists combined estrogens (CE) without interference activity. CE can be dividedinto two categories, sulfate conjugate estrogens and glucuronic acid conjugate estrogens.CE-G can be decomposed into free estrogen during wastewater transportation within afew hours. CE-S break down slower in the water, whose content is one-second of freeestrogen.It can be hydrolysis into free estrogen by arylsulfatase (AryS). E1-3S is themost representative conjugated estrogens. This paper focuses on the activatedmechanism of E1-3S,mainly including the survey of environmental factors values andarylsulfatase activity in sewage treatment plants and receiving waters,the effects oftypical environmental factors on the activity of arylsulfatase, developing a method forsimultaneous monitoring of free estrogens (E1, E2, EE2) and conjugated estrogen(E1-3S), analysising change of estrogens concentration along the process of domesticsewage treatment,determining the reaction rates of sulfate estrone reaction ratesconstant and summarizing the relationship between E1-3S reaction rates constant andArys activity in the final.Sample points is the water inlet,anaerobic tank,aerobic tank,water outlet andreceiving water.The pH,temperature,inorganic sulfates,organic matter content and lightintensity are environmental factors for determination in the experiment. This experimentmeasured the AryS activity of five sampling points values based on the method fordetermination the activity of AryS. According to the measured values of environmentalfactors and arylsulfatase activity,this paper received the influence of environmentalfactors on the activity of aryl-sulfatase through analysis of single factor experimentresults.The single factor results showed that temperature, inorganic sulphate content andorganic matter content are the major factors for affecting the activity of AryS. Three-level three-factor orthogonal experiments studied the combined effect of variousfactors on the activity of AryS. Experimental results showed that the distinctive order isorganic matter content> temperature> inorganic AryS activity is highest at atemperature of20℃while inorganic sulfate concentrations is50mg/L and the organicmatter content is0.02g.Experiments collected water samples from wastewater treatment plant and waterreceiving bodies separately.The water samples collected were carried outpretreatment,including filtration, solid-phase extraction and evaporation of dissolutionand so on. Water samples pretreated were analysied for HPLC-MS/MS to monitoredfree estrogens (E1, E2, EE2) and conjugated estrogen (E1-3S). The results ofHPLC-MS/MS analysis have high recovery rate which prove that the method is feasible.Compared to other methods, this method can reduce water sampiles volume, simplifypreprocessing and provide supports for studing the migrations, changes and fatecharacteristics of endocrine disrupting compounds in water. Experimental resultsshowed that the four types of estrogen concentrations in wastewater sampling points arein the order of E1>E2>E1-3S> EE2. The estrogen concentrations gradually reducedalong the sewage treatment processes. E1-3S content cover25~50%of E15%~20%of ΣSE. If all the E1-3S fall apart, the concentration of ΣSE and E1will increase10%~50%.Most enzymatic reactions follow first order reaction patterns. The reaction rateconstant of estrone sulfate enzymatic hydrolysis in the condition of aryl sulfate wasdetermined in this experiment.The decomposition rates of estrone sulfate andaryl-sulfatase activity are positively correlated. When AryS activity value is close to theone of sewage outlet, concentration of E1-3S enzyme-catalyzed hydrolysis is143ng/Lwhile the chemical react for72h. When AryS activity value is close to the one ofaerobic tank, concentration of E1-3S enzyme-catalyzed hydrolysis is half of its originalconcentration while the chemical react for30h. Conjugated estrogens can bedecomposed a lot of free estrogen having interference activity within24h. Theirenvironmental risks should be taken into account.