Pharmaceuticals in the Environment

Glossary

CAS Number

CAS Number is a numeric designation given to a specific chemical compound by the Chemical Abstract Service

EC

Effective Concentration; for example, EC50 is the effective concentration where 50% of the organisms respond

ECOSAR

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.

ECOSAR Data

Lowest concentration causing toxicity for each organism group as predicted using the ECOSAR program and reported May 2005 by Sanderson et al. See bibliographic citation ^k.

Formulation

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).

Half-Life

The time required for a chemical to degrade to half its initial concentration

K_oc

Contaminant organic carbon partition coefficient, proportion sorbed to carbon in soil

K_ow

Contaminant octanol-water partition coefficient; octanol/water ratio

log

The logarithm of a number

Molecular Weight

The sum of the relative atomic masses of the constituent atoms of a molecule

pH

p(otential of) H(ydrogen); provides a measure on a scale from 0 to 14 of the acidity or alkalinity of a solution

Solubility

The quantity of a particular substance that can dissolve in a particular solvent