[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]
macropore Soil pore larger than 1 mm
in diameter including interparticle void, earthworm or rodent burrow,
drying crack, and decayed root channel. See preferential
flow.
margin of safety (MOS) Ratio of the
highest estimated or actual level of exposure to a pesticide and the
toxic threshold level (usually the NOEC or NOEL). See
also uncertainty factor. (US-EPA,
1992)
market basket survey Pesticide
residue monitoring on a wide range of food items collected from
consumer points of sale and in proportions approximating consumption
patterns in the local population. Samples are prepared for analysis
according to Codex guidelines i.e. minimal preparation. See also total
diet study.
matrix The material or component sampled for
pesticide residue studies.
maximum residue limit (MRL) Maximum
concentration of a residue that is legally permitted or recognised as
acceptable in, or on, a food, agricultural commodity or animal feedstuff
as set by Codex or a national regulatory authority. The term tolerance
used in some countries is, in most instances, synonymous with MRL. Normally
expressed as mg/kg fresh weight. (after FAO, 1986)
maximum tolerated dose (MTD)
Highest dose of a pesticide in chronic toxicity testing that is expected,
on the basis of sub-chronic studies, to produce only limited toxicity when
administered for the duration of the test period. (Duffus, 1993)
median effective concentration (EC50)
Statistically derived concentration of a pesticide in an environmental
medium expected to produce a certain effect in 50% of the test organisms in
a given population under defined conditions. (Duffus, 1993)
median lethal concentration
(LC50) Statistically derived concentration of a pesticide in an
environmental medium expected to kill 50% of test organisms in a given population
under defined conditions. (Duffus, 1993)
median lethal dose (LD50)
Statistically derived dose of a pesticide expected to kill 50% of test
organisms in a given population under a defined set of conditions. Normally
expressed as mg of test material per kg of body weight of the organism. (Duffus,
1993)
mesocosm See model ecosystem.
metabolism Sum total of all physical and
chemical processes that take place within an organism; in a narrower
sense, the physical and chemical changes that occur for a pesticide
within an organism. It includes uptake and distribution within the body,
changes (biodegradation), and elimination
of pesticides and their metabolites.
metabolites Any intermediate or
product resulting from metabolism. (after Duffus, 1993)
microcosm See model ecosystem.
mineralisation Conversion of an element
from an organic form to an inorganic form. Mineralisation of pesticides
most commonly refers to the microbial degradation to carbon dioxide
as a terminal metabolite. See also immobilisation.
model Experimental or mathematical simulation
of chemical behaviour in a specific environment. (ASTM, 1984)
model calibration Testing
of a model with known input and output information for adjustment or estimation
of factors for which data are not available. (ASTM, 1984)
model, computer Assembly of
numerical techniques (algorithms), bookkeeping, and control language (i.e.
the computer program) comprising a mathematical model and which carries out
acceptance of input data and instructions through to delivery of output. (after
ASTM, 1984)
model, conceptual Qualitative
depiction of a specific environment that describes the linkages between the
different compartments. A conceptual model is required before a quantitative
simulation model can be developed. (Cohen et al., in press)
model ecosystem Man-made study
system containing associated organism and abiotic components that is
large enough to be representative of a natural ecosystem,
yet small enough to be experimentally manipulated. There is some subjective
differentiation between larger, outdoor model ecosystems (mesocosms)
and smaller, generally indoor model ecosystems (microcosms).
model validation Comparison
of model results with numerical data independently derived from experiments
or observations of the environment. (ASTM, 1984)
model verification Examination
of the numerical technique in the computer code to ascertain that it truly
represents the conceptual model and that there are no inherent numerical problems
with obtaining a solution. (ASTM, 1984)
multiresidue method Analytical
method which measures a number of pesticide residues simultaneously.
nebulisation Formation of an aerosol of
very small liquid particles (fog) or solid particles (smoke) from a pesticide
formulation, generally for fumigation of an enclosed space such as a glass-house.
NMR Nuclear magnetic resonance spectroscopy.
non-target organism Organism affected
by a pesticide although not an intended object of its use.
no-observable effect concentration/
level (NOEC/NOEL) Highest concentration or amount of pesticide
in the test system that causes no observable biological effect to the
target organism. (after US-EPA, 1992) See also Ecotoxicologically
relevant concentration, PNEC.
NPD Nitrogen-phosphorus detector or detection
for gas chromatography (cf AFID and TID).
> Synopsis
> Preface
> References
