In recent decades it has been confirmed that some chemicals found in river water so called EDCs (Endocrine Disrupting Chemicals), are capable to disturb the normal function of the endocrine system, of both humans and wildlife. Many cases of abnormalities in wildlife, particularly those associated with reproductive functions, are suggested to be caused by exposure to EDCs. Natural estrogens, such as 17ɿ-estradiol (E2), estrone (E1), estriol (E3) are considered as EDCs, which are commonly detected in surface water.

Though several natural estrogens have been detected in municipal STP effluents, there is still a lack of information concerning the behavior of the estrogens during the STP process. In this study, the measurement of natural estrogens in each steps of the STP process were performed so that the behavior of the estrogens during sewage treatment process can be predicted. However, since a sufficiently sensitive analytical procedure for detecting the estrogen concentration in sewage water requires the use of a sophisticated detection equipment and requires a long and complicated steps of sample preparation, the present study is also aimed to develop a simple and appropriate method to measure estrogens in the environment using LC-MS. It is believed by the author that since natural estrogens are not easy to evaporate, LC-MS could be used in the experiment as long as an appropriate sample pretreatment method is employed.

Two pretreatment methods were proposed in this study, they are: a modification of Snyder method (SM method) and a proposed alternative method (PA method). The methods basically consist of enrichment, extraction and clean up steps.

Dichloromethane was used for extraction in SM method and 35% acetone in hexane was used in PA method. The same clean up step and detection conditions were performed in both methods.

The methods were applied on the sewage samples taken from an STP located close to Tamagawa river, in which high estrogen activities have been observed.

The results strengthened the possibility of estrogens formation during aeration/ activated sludge process. The quality of effluent from the STP is better than that of other STPs in other countries as found in the literature. However still does not give any assurance concerning whether or not the current effluent is safe for wildlife.