Review of suggested testing methods for endocrine-disrupting chemicals

Recent concern about the possible impact of exposure to endocrine-disruptin g chemicals (EDCs) on humans and wildlife has led to a need for the develop ment of regulatory test methods to facilitate identification of endocrine- disrupting substances and their effects, both at the stage of product devel opment, and when they are present in the environment. Whilst structural act ivity relationships (SARs) and in vitro tests have potential utility for th e rapid identification of suspect chemicals, they do not accurately mimic e ffects in whole animals and are therefore complementary to, not substitutes for, in vivo tests on whole animals. A tiered structure for testing has be en suggested by scientists at various workshops and is reiterated here. Pri oritisation screens involving in vitro and in vivo short-term tests should be followed by partial or whole life-cycle studies on whole animals with a variety of reproductive and developmental end-points. Whilst existing in vi vo mammalian test methods are broadly suitable as screens for assessing pot ential endocrine-disrupting effects in mammalian wildlife, it is uncertain if these assays would be of use as screens for other classes of vertebrate wildlife, due to differences in endocrine function. Existing full and parti al life-cycle tests with some avian and fish species could also identify en docrine disrupters; however, these long term tests are not suitable for rou tine screening without modification. Several non-regulatory tests are suita ble for development and could be applied for regulatory purposes after modi fication and standardisation. Despite the absence of properly validated int ernationally agreed test methods, several countries have already taken acti on to restrict or prevent the use/discharge of certain endocrine-disrupting chemicals.