Overview, Conclusions, and the Path Forward

Careful control of the conditions of synthesis of chlorinated phenols will reduce the formation of dioxins, and this is now the rule for avoiding their formation. Likewise, macro-contaminants, such as inactive isomers, are now recognized as unwanted components of chemicals that may cause harm in the environment or to humans. However, a good understanding of the mechanism of toxic action and how the chemical interacts with the receptor is needed to be able to recognize that toxicity is isomer-specific and to then use this in the intelligent design of low-risk products. 

By screening chemicals for properties that increase risk to the environment, it is possible to move towards the production of safer commercial products. The design of chemicals with reduced potential for adverse effects in the environment may be complicated by a tradeoff between the properties of the chemical that confer benefits and those that confer risks to the environment. This is not new and is an issue with all human activities. In fact, the adverse effects of chemicals synthesized for use by humans may be far less significant in the environment than other activities such as urbanization, use of fossil fuels, and conversion of natural areas to the production of food and fiber. Clearly, the quest for greener chemicals must be conducted in a framework of the evaluation of risks and benefits to humans and the environment. 

There is no formal framework for identifying green chemicals and using this framework in intelligent design for lower risk to the environment. There are, however, a few properties that are key to this objective. Fate in the environment 

Acute toxicity tests with plants, invertebrates and vertebrates 

Acute TTC screen, specific mode of action or functional classes 

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