ABSTRACT
When pollutants enter living organisms, they cause a variety of changes (for general accounts, see Guthrie and Perry, 1980; Hodgson and Levi, 1994; Timbrell, 1995). These changes (bioeffects) are, broadly speaking, of two kinds: those that serve to protect the organisms against the harmful effects of the chemical and those that do not. Some examples of both types are given in Table 7.1.
