[A]
[B] [C] [D]
[E] [F] [G]
[H] [I-J-K] [L]
[M-N] [O-P] [Q-R]
[S] [T] [U-V]
[W-X-Y-Z]
laboratory sample Sample or subsample(s)
sent to or received by the laboratory.
lag phase Period which may precede commencement
of rapid degradation of a pesticide by a microbial population. It is
the period needed either for induction of microbial enzymes or for growth
of the microbial population to adequate size. See also enhanced
degradation. (after US-EPA, 1992)
LC50 See median
lethal concentration.
LD50 See median
lethal dose.
leaching Process by which a pesticide
moves downward through the soil profile in the aqueous phase.
leachate Aqueous phase percolating
through a soil profile or a soil column.
limit of detection (LOD) Lowest
concentration of a pesticide residue
in a defined matrix where positive identification can be achieved
using a specified method.
limit of quantitation (LOQ)
Lowest concentration of a pesticide
residue in a defined matrix where
positive identification and quantitative measurement can be achieved
using a specified method. The term limit of quantitation is preferred
to limit of determination to differentiate it from LOD.
LOQ has been defined as 3 times the LOD (Keith, 1991) or as 50%
above the lowest fortification level used to validate the method (US-EPA,
1986).
limit of reporting Practical
limit of residue quantitation at or above the LOQ. The limit
of quantitation for a defined matrix
and method may vary between laboratories or within the one laboratory
from time to time because of different equipment, techniques and reagents.
lipophilicity Affinity for fat
as described by partitioning behaviour between water and an immiscible
organic solvent, favouring the latter, and which correlates with bioconcentration.
See also octanol-water partition coefficient.
(after Duffus, 1993)
lot Quantity of material which is assumed to be
a single population for sampling purposes. See also batch.
lysimeter Device for measuring leaching
losses from a column or block of soil. The simplest lysimeters may be
devices for sampling a portion of the water leaching
through a natural sediment or soil (e.g. suction lysimeter), whereas
more elaborate lysimeters may involve the confinement of an entire segment
of soil from which all leachate is collected
(e.g. monolithic lysimeter).
> Synopsis
> Preface
> References
