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[H] [I-J-K] [L]
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[S] [T] [U-V]
[W-X-Y-Z]
safener A substance added to a pesticide
formulation to eliminate or reduce phytotoxic effects of the pesticide
to certain crops. See also adjuvant.
safety factor See uncertainty
factor.
sample Portion of material selected
from a larger quantity of material so that it is representative of the
whole. See also aggregate sample, aliquot,
composite sample, control
sample, increment sample, laboratory
sample, primary sample, random
sample, retention sample, subsample,
test portion and test
sample.
sampling plan Predetermined procedure
for the selection, withdrawal, preservation, transportation, and preparation
of the portions to be removed from a population as samples. (Horwitz, 1990)
SEC Size exclusion chromatography (cf GPC).
SFC Supercritical fluid chromatography.
SFE Supercritical fluid extraction.
soil partition coefficient (Kd)
Experimental ratio of a pesticide's concentration in the soil to that
in the aqueous (dissolved) phase at equilibrium. It is valid only for
the specific concentration and solid/solution ratio of the test. The
Kd is a distribution coefficient reflecting the relative affinity
of a pesticide for adsorption by soil solids and its potential for leaching
movement through soil. See also Koc.
soil incorporation Application
of a pesticide to soil by mixing or injection into the soil body.
soil organic partition coefficient
(Koc) Ratio of a pesticide concentration sorbed in the organic
matter component of soil or sediment to that in the aqueous phase at
equilibrium. The Koc is calculated by dividing the Kd
value by the fraction organic carbon present in the soil or sediment
(see soil organic matter).
soil organic matter Organic
fraction of the soil, including both fresh and aged residues (e.g. humus)
of biological origin. Organic carbon refers to that portion of the soil measured
as carbon in organic forms, and the organic matter content of soil is assumed
to be approximately 1.72-fold that of the organic carbon content.
sorption Removal of pesticide from solution
by soil or sediment via mechanisms of adsorption
and absorption.
SPE Solid phase extraction.
specimens Samples
collected from a system for examination, analysis, or storage.
spiked sample (fortified sample) Control
sample with a known amount of pesticide added. Used to test the
accuracy (especially the efficiency of recovery) of an analytical
method. (after Thompson and Wood, 1995). See also reference
material.
spray drift Movement beyond the target
area of airborne droplets or vapour of pesticide formulation originating from
aerial or ground-based spraying operations.
spreader See wetting
agent.
standard solution, primary
Standard prepared by dissolving a weighed amount of an analytical
standard pesticide in a known volume of solvent.
standard solution, secondary
Standard prepared by dilution of an aliquot of a primary
standard solution with a known volume of solvent, or by subsequent
serial dilutions; or a standard solution measured by reference to a
primary standard solution.
sticker Formulant
which increases the adhesiveness of a formulation applied to a surface.
(FAO, 1995). See also wetting agent.
storage stability test For a
pesticide formulation,
a test which measures the chemical and physical stability of the product
stored under defined, often worst case, conditions. For pesticide
residues, a test which measures stability of residues in stored
analytical samples, usually held under frozen conditions at a specified
temperature.
subsample
- portion of the sample obtained by selection
or division;
- individual unit of the lot taken as part of the sample;
- final unit of multistage sampling. (Horwitz, 1990)
surfactant A formulant
for reducing interfacial tension of two boundary surfaces, thereby increasing
the emulsifying, spreading, dispersability or wetting properties of
liquids or solids. (FAO, 1995.)
surveillance Systematic sampling
and residue analysis of commodities, and collation and interpretation of data,
in order to ensure compliance with established MRLs. Surveillance may be directed
at domestic, imported or exported commodities.
suspension concentrate (SC) Formulation
in which the active ingredient is in the form of a stable dispersion of fine
particles in water or organic liquid. (GIFAP, 1989)
synergist Substance, which, while
formally inactive or weakly active, can significantly enhance the activity
of the active ingredient in a formulation.
systemic A systemic pesticide
is capable of being translocated to sites other than where it was absorbed
in sufficient quantities to be biologically effective.
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