Quantitative Structure Property Relationships (QSPRs), help environmental fate scientists to initially understand how a chemical’s properties behave in different environmental compartments. From this starting point, models for predicting a molecule’s environmental fate can be made, speeding up the risk assessment process.
Most wastewater goes to wastewater treatment plants where fate processes act on the ingredients. After treatment, some of the product ingredients may reach the environment. The environment consists of the soil, water, groundwater, sediment and atmospheric compartments. To predict which compartment our ingredients end up in, we use QSPRs to understand how a chemical behaves (i.e., its chemical properties), fate processes to generate data or to refine the data from the QSPR, and environmental fate models to predict where the chemical will end up. We use monitoring studies to verify the prediction made by the models so we can use models for future predictions with more confidence.
The first step in estimating chemical properties is often to use a Quantitative Structure Property Relationship (QSPR). Every molecule has many different chemical properties. These properties include things like solubility in water, volatility (how quickly the molecule evaporates), the boiling and melting point and the solubility of the molecule in fat. Each of these properties tells the fate scientists something about how the chemical will act in the environment or in an animal. QSPRs help scientists understand whether a compound is likely to bioconcentrate in fish, biodegrade and be converted to CO2, etc. From any one property, it is difficult to fully understand what will happen to a chemical in the environment. To get a full understanding of where an ingredient goes in the environment, many chemical properties are used with environmental fate models. If environmental behaviour can be predicted with equations, the process of risk assessment can be greatly sped up.
In some cases, QSPRs alone do not provide sufficient data to accurately estimate environmental concentrations. When this occurs, environmental fate testing is conducted.