<unk>  is the accumulation of a chemical in or on an organism when the source of chemical is solely water.<unk>  is a term that was created for use in the field of aquatic toxicology.<unk>  can also be defined as the process by which a chemical concentration in an aquatic organism exceeds that in water as a result of exposure to a waterborne chemical. There are several ways in which to measure and assess bioaccumulation and<unk> . These include: octanol-water partition coefficients (KOW),<unk>  factors (BCF), bioaccumulation factors (BAF) and biota-sediment accumulation factor (BSAF). Each of these can be calculated using either empirical data or measurements as well as from mathematical models. One of these mathematical models is a fugacity-based BCF model developed by Don Mackay.<unk>  factor can also be expressed as the ratio of the concentration of a chemical in an organism to the concentration of the chemical in the surrounding environment. The BCF is a measure of the extent of chemical sharing between an organism and the surrounding environment. In surface water, the BCF is the ratio of a chemical's concentration in an organism to the chemical's aqueous concentration. BCF is often expressed in units of liter per kilogram (ratio of mg of chemical per kg of organism to mg of chemical per liter of water). BCF can simply be an observed ratio, or it can be the prediction of a partitioning model. A partitioning model is based on assumptions that chemicals partition between water and aquatic organisms as well as the idea that chemical equilibrium exists between the organisms and the aquatic environment in which it is found
Bioconcentration
Countercurrent exchange
Selective reabsorption
Enhanced permeability and retention effect
Isobaric counterdiffusion
Augmented renal clearance
Reabsorption
Solvent drag