National Centers for Coastal Ocean Science
Pharmaceuticals in the Environment
CAS Number is a numeric designation given to a specific chemical compound by the Chemical Abstract Service
Effective Concentration; for example, EC50 is the effective concentration where 50% of the organisms respond
Program available from the U.S. Environmental Protection Agency that uses structure-activity relationships to predict aquatic toxicity of chemicals based on the similarity of their structure to chemicals with previously measured aquatic toxicity.
Lowest concentration causing toxicity for each organism group as predicted using the ECOSAR program and reported May 2005 by Sanderson et al. See
Generally reserved for commercial preparation prior to actual use and does not include the final dilution (e.g.; Baythroid, 2,4-D). Also included in this category are organic compounds with no pesticidal activity (e.g.; PCB, dioxin).
The time required for a chemical to degrade to half its initial concentration
Contaminant organic carbon partition coefficient, proportion sorbed to carbon in soil
Contaminant octanol-water partition coefficient; octanol/water ratio
The logarithm of a number
The sum of the relative atomic masses of the constituent atoms of a molecule
p(otential of) H(ydrogen); provides a measure on a scale from 0 to 14 of the acidity or alkalinity of a solution
The quantity of a particular substance that can dissolve in a particular solvent