ABSTRACT
This chapter demonstrates the significant role that essential metal regulation may play in toxic metal assimilation by terrestrial invertebrates, and how, in turn, this may determine their adaptation to life in a metal-contaminated environment. A small number of metals can properly be described as “essential,” for which organisms have mechanisms of uptake and regulation. Terrestrial animals rely on their digestive tracts for essential metal assimilation and have several mechanisms for storage and excretion. For plants and animals to survive in polluted habitats, they have to distinguish between the metals they need and those likely to poison them. Marine mollusks and arthropods show protein polymorphisms which allow for enzyme viability under different metal insults. Concentrations of Ca are elevated in the soft tissues of many terrestrial animals exposed to toxic metal pollution, including annelids and mollusks. The lower rates of metal assimilation by insects are probably a function of low demand, due in part to a lack of respiratory pigments.
