Log10Kow

log10Kow, often referred to as log Kow or Kow, is a dimensionless quantity used in environmental science and chemistry to describe the partitioning behavior of a chemical compound between octanol and water. It is the logarithm (base 10) of the octanol-water partition coefficient (Kow). The Kow value itself is the ratio of the concentration of a chemical in octanol to its concentration in water at equilibrium. A higher log10Kow value indicates that the chemical is more soluble in octanol, a nonpolar solvent, than in water, a polar solvent. Conversely, a lower log10Kow value means the chemical is more hydrophilic.

This parameter is crucial for predicting how a chemical will behave in the environment. For instance, chemicals with high log10Kow values tend to be lipophilic, meaning they are likely to accumulate in fatty tissues of organisms, a process known as bioaccumulation. They are also more likely to adsorb to organic matter in soil and sediments, reducing their mobility in aqueous systems. Conversely, chemicals with low log10Kow values are more water-soluble and tend to remain in the aqueous phase, increasing their potential for transport in water bodies.

Log10Kow is commonly used in risk assessment, environmental fate modeling, and the design of wastewater treatment processes. It helps scientists estimate a chemical's potential for persistence, bioaccumulation, and toxicity (PBT criteria). Experimental determination of log10Kow involves shaking a known concentration of the chemical in both octanol and water until equilibrium is reached and then measuring the concentrations in each phase. It can also be estimated using computational methods based on the chemical structure.