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EASI - Glossary of Terms

a.i.
Active ingredient

Alevin
Newly hatched fish, before the fry stage. Usually refers to salmon.

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

d
Day; for example as in 10d LC50

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

F
Flow-through bioassay; for example 96h LC50,F

Fry
Small fish, especially young, recently hatched fish

h
Hour; for example 96h LC50

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

IC
Inhibitory Concentration; for example, IC50 is the concentration for 50% inhibition, usually growth by microorganisms

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

Kow
Contaminant octanol-water partition coefficient; octanol/water ratio

LC
Lethal Concentration; for example, LC50 is the concentration causing death in 50% of the test organisms exposed

LD
Lethal Dose; for example, LD50 is the dose causing death in 50% of the test organisms exposed

log
The logarithm of a number

m
Month; for example 3m LC50

MATC
Maximum Acceptable Toxicant Concentration

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

Molting
Periodic shedding of the cuticle in arthropods or the outer skin of reptiles.

NOEC
No Observed Effect Concentration; the highest tested concentration not causing an effect

NR
Mean concentration of test substance reducing viability; for example NR50 is the mean concentration that reduces viability to 50% of controls

Parr
(1) A young salmon during its first two years of life, when it lives in fresh water.
(2) The young of various other fishes.

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

S
Static bioassay; for example 96h LC50,S

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

y
Year; for example 1y LC50