Complex factors in hydrocarbon/water, soil/water and fish/water partitioning.

Many partitioning and toxicological events that appear to correlate simply with log P (octanol/water) can be resolved into greater detail by a factoring process. Log P can be separated into lipophilic (PL) and hydrophilic (PH) contributions that combine well with polarizability (MR) and hydrogen-bonding (HB) to describe partitioning and non-specific binding in phases that differ greatly from n-octanol. In addition, hydrogen-bonding can be factored into donor groups (HBD) and acceptor groups (HBA) for stronger correlations and greater mechanistic insight. These descriptors are applied to a variety of problems in simple partitioning, soil organic matter binding, bioaccumulation in fish, and aquatic narcosis and toxicity.