Abstract
Endocrine disrupting chemicals and natural estrogens exist in aquatic environment and disrupt the endocrine system of aquatic organisms. Consequently, in order to evaluate the estrogenic activity of these compounds, we have investigated relative binding affinity of estrogen receptors (α and β) of some endocrine disruptor and estrogens, and derived a estrogen receptor binding activity factor (EAF) which is expressed in values relatively to a standard material, diethylstilbestrol (DES) . In regard to the EAF, which is based on the principle of TEF (dioxins), basic assumption is that the estrogenic activity of different chemicals are additive, and results of our present study support this assumption. Estrogen activity equivalent (EAEQ) value in water sample is calculated chemical residue data and their EAFs. The evaluation based on EAEQ was applied for the river water collected in Matsuyama Plain. The results show that the EAEQ values derived from endocrine disruptors are higher than those of estrogen compounds derived from humans and animals. EAF and EAEQ are useful tool evaluate the pollution caused by endocrine disruptors and to take a plan for reduction of the pollution.
