Natural and synthetic steroidal estrogens (estrone, 17 -estradiol and 17 -ethinylestradiol) are endocrine disrupters, that are discharged consistently from the sewage treatment works into surface waters, thereby causing endocrine disrupting effects to aquatic organisms at trace concentrations (nanogram per litre). Several years of research have been focused on their fate, behaviour and removal in the environment but primarily in the sewage treatment works which acts as a sink for these compounds. This review attempts to summarize the factors involved in the removal of these chemicals from the sewage treatment works. Biological processes, and to a limited extent physio-chemical properties, play a vital role in the endocrinal deactivation of these compounds. The efficiency of these processes is highly dependent on operating parameters (such as sludge retention time, redox potential, etc) that govern the secondary treatment process of a functional sewage treatment works. Although advanced treatment technologies are available, cost and operational considerations do not make them a sustainable solution.

This paper discusses the requirement for, and presents an analytical procedure for, the determination of four unconjugated steroid hormones and a conjugated steroid (estrone-3-sulfate) in wastewaters. The method quantifies the steroids by LC/MS/MS following solid phase extraction and a two stage clean-up procedure. Samples were extracted using C18 cartridges and eluates were then purified by gel permeation chromatography, followed by a further clean-up step on an aminopropyl cartridge.

Abstract. This study investigated operational factors influencing the removal of steroid 18 estrogens and alkylphenolic compounds in two sewage treatment works, one a 19 nitrifying/denitrifying activated sludge plant and the other a nitrifying/denitrifying 20 activated sludge plant with phosphorus removal. Removal efficiencies of >90% for 21 steroid estrogens and for longer chain nonylphenol ethoxylates (NP 4-12 EO) were observed 22 at both works, which had equal sludge ages of 13 days. However, the biological activity 23 in terms of milligrams of estrogen removed per tonne of biomass was found to be 50-60% 24 more efficient in the nitrifying/denitrifying activated sludge works compared to the works 25 which additionally incorporated phosphorus removal. A temperature reduction of 6°C 26 had no impact on the removal of free estrogens, but removal of the conjugated estrone-3-27 sulphate was reduced by 20%. The apparent biomass sorption (LogKp) values were 28 greater in the nitrifying/denitrifying works than those in the nitrifying/denitrifying works 29 with phosphorus removal for both steroid estrogens and alkylphenolic compounds 30 possibly indicating a different cell surface structure and therefore microbial population. 31The difference in biological activity (mg tonne -1 ) identified in this study, of up to seven 32 2 times, suggests that there is the potential for enhancing the removal of estrogens and 33 alkylphenols if more detailed knowledge of the factors responsible for these differences 34 can be identified and maximised, thus potentially improving the quality of receiving 35 waters. 36 37 Introduction 38

The fate and behaviour of two groups of endocrine disrupting chemicals, steroid estrogens and nonylphenol ethoxylates, have been evaluated during the anaerobic digestion of primary and mixed sewage sludge under mesophilic and thermophilic conditions. Digestion occurred over six retention times, in laboratory scale reactors, treating sludges collected from a sewage treatment works in the United Kingdom. It has been established that sludge concentrations of both groups of compounds demonstrated temporal variations and that concentrations in mixed sludge were influenced by the presence of waste activated sludge as a result of transformations during aerobic treatment. The biodegradation of total steroid estrogens was>50% during primary sludge digestion with lower removals observed for mixed sludge, which reflected bulk organic solids removal efficiencies. The removal of nonylphenol ethoxylates was greater in mixed sludge digestion (>58%) compared with primary sludge digestion and did not reflect bulk organic removal efficiencies. It is apparent that anaerobic digestion reduces the concentrations of these compounds, and would therefore be expected to confer a degree of protection against exposure and transfer of both groups of compounds to the receiving/re-use environment.

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This paper presents a method for the determination of alkylphenols, alkylphenol . Shorter chain APEO were present in higher proportions in the suspended solids, due to their higher affinity to particulate matter compared to the long chain oligomers.

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