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P

PAH

Polycyclic Aromatic Hydrocarbons formed by combustion of fossil fuels, municipal solid waste, or any materials that contain organic carbon. They are ubiquitous in urban environments and are good markers of urban activities. They are of particular concern because some are potent toxins and some can be highly persistent in the environment.

Partition Coefficient

The potential of a substance to bioaccumulate is related to its solubility and potential to partition into fats. Thus the octanol/ water Partition Coefficient can be used to predict potential to bioaccumulate in organisms. This is only valid for non-ionic substances and does not take into account bio-availablity of the substance.

Persistence

Defining how substances break down

PIE

Pharmaceuticals in the Environment

PNEC

In order to assess the potential impact of a chemical compound in the environment, a realistic estimation of its probable Predicted No Effect Concentration is required. This will include an assessment of its potential to degrade and partition between environmental compartments.

The environmental risk assessment is calculated from the ratio between the toxicity and the environmental concentration.

Predicted Environmental Concentration (PEC)    = Risk Factor

Predicted No Effect Concentration (PNEC)