ABSTRACT
Risk assessment of chemicals is an organized process that aims to describe and estimate the likelihood of adverse outcomes from environmental exposure to chemicals (US PCCRARM 1997), and is applied for both humans and ecosystems. Risk assessment traditionally focuses on single chemicals. However, awareness is growing that exposure to single substances is the exception rather than the rule. In practice, humans and ecological receptors are often exposed to multiple chemicals that may or may not interact, that is, influence each other by physical, chemical, or biological means before or after reaching the molecular site of toxic action.
