Assessing the risks of chemicals to man and the environment is based on comparing exposure to chemicals with their respective hazardous properties. However, there are differences in the criteria for deciding whether the level of exposure represents an acceptable or unacceptable risk. For man, decision criteria are focused on protecting the individual and regulations are applied relatively consistently around the globe. For the environment, protection goals are less clearly defined and not consistent across regional regulations. Regional environmental policies take a cost-benefit approach to environmental impacts. There are two possible extremes for doing this: i) a precautionary approach aiming for zero release of chemicals into the environment (costs judged to be more important than benefits); ii) uncontrolled release with no effective management to mitigate impacts (benefits judged to be more important than costs). Most environmental regulatory schemes adopt an approach somewhere between these extremes. For example, some effects on individuals may be accepted if the population is unaffected or if it recovers from episodic exposure. For this approach to make sense, protection goals need to be suitably defined. Reviews of current regulations indicate that protection goals are only generally defined leaving a lack of clarity on how to achieve such protection (EFSA, 2010; Hommen et al, 2010).
Discussion of current chemical regulation schemes has led to calls for changes in the way environmental toxicity thresholds are derived. The use of a limited number of species toxicity tests together with application factors is tenuously linked to protection goals and will be over-protective in some cases and potentially under-protective in others. Given that there are relatively few examples of major impacts (e.g. TBT, DDT, diclofenac), from the regulated use of thousands of chemicals in commerce, it may be that the current approach tends to be over-protective. This could be restricting the societal benefits of chemicals. On the other hand, the uncertainties in the approach may underestimate effects, for example, in potentially sensitive ecosystems such as coastal marine reefs or in assessing endocrine disruption of chemical mixtures.