Fate

click to enlarge
  In the course of a day, people around the world are likely to use several P&G products. You may brush your teeth with toothpaste (Crest), shampoo (Pantene) your hair, use detergent (Tide or Ariel) to launder your clothes and dish soap (Fairy or Dawn) to wash your dishes. After you use each of these products, the wash water disappears down the drain. But where do those chemicals go? Do they end up in the environment? In the ocean? Will they be around in a week or two? Do they get into the food supply? Does anyone worry about these questions?

When we sit down and think about it, a lot of questions do come up about the P&G products we use and where they go after we use them. We refer to this as studying the fate of the ingredient. The key questions fate scientists try to understand are:

Many consumer products are washed down the drain after use. These products and their ingredients travel through sewers to the local wastewater treatment plant (see chart at left).

click to enlarge To study the fate of an ingredient, we usually start with computer-based tools (see our QSPR page) to predict the chemical properties of the substance. This information is combined with measured fate data and with the amount of the ingredient sold. Then a computer based fate model predicts the concentrations of our ingredients in each environmental compartment. To ensure that these models are accurate, the results are often compared with measured environmental concentrations. These concentrations are determined during monitoring studies.

Most wastewaters go to wastewater treatment plants where fate processes act on the ingredients. After treatment, some of the ingredients in the product 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 (Quantitative Structure Property Relationships) 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.