bait A food or other substance used to
attract a pest to a pesticide or trap where it can be destroyed.
batch Quantity of material which is known
or assumed to be produced under uniform conditions. (Horwitz, 1990)
benthos Non-planktonic animals (not
being suspended in water) associated with freshwater substrata (upper layer
of the sediment in rivers and ponds) at the sediment-water interface. (Wetzel,
1983)
bioaccumulation Progressive
increase in the amount of a substance in an organism or part of an organism
which occurs because the rate of intake exceeds the organisms ability to remove
the pesticide from the body. (after Duffus, 1993)
bioactivation Transformation
of a pesticide within an organism into a more biochemically active metabolite.
bioconcentration Process leading
to a higher concentration of a pesticide in an organism than in environmental
media to which it is exposed. (after Duffus, 1993)
bioconcentration factor (BCF)
Ratio between the concentration of pesticide in an organism or tissue
and the concentration in the environmental matrix (usually water) at apparent
equilibrium during the uptake phase. (after Rand and Petrocelli, 1985)
bioavailability Extent to
which a pesticide residue can be taken up into an organism from its food and
environment, and the rate at which this occurs. (Duffus, 1993)
biodegradation Conversion or breakdown
of the chemical structure of a pesticide catalysed by enzymes in
vitro or in vivo, resulting in
loss of biological activity. For hazard
assessment, categories of chemical degradation include:
- Primary - loss of specific activity.
- Environmentally acceptable - loss of any undesirable activity (including
any toxic metabolites).
- Ultimate - mineralisation
to small molecules such as water and carbon dioxide. (after Duffus,
1993)
biological indicator Species
or group of species which is representative and typical for a specific status
of an ecosystem, which appears frequently enough to serve for monitoring and
whose population shows a sensitive response to changes, e.g. the appearance
of a pesticide in the ecosystem. (US-EPA, 1992)
biological assessment of exposure
Assessment of exposure of a living organism to pesticides using
biological specimens (blood, urine etc.) taken in the environment (workplace,
field etc.) with analysis either directly by chemical determination of parent
or metabolite, or indirectly by measurement of a relevant biochemical parameter
(e.g. plasma cholinesterase activity for organophosphorus compounds). (after
Duffus, 1993)
biomagnification Bioaccumulation
of a pesticide through an ecological food chain by transfer of residues
from the diet into body tissues. The tissue concentration increases
at each trophic level in the food web when there is efficient uptake
and slow elimination. (Rand and Petrocelli, 1983)
biomarker Indicator (molecular, biochemical,
cellular or organism) signalling an event or condition in a biological system
or sample and giving a measure of exposure to, effect of, or susceptibility
to, a xenobiotic. (after Duffus, 1993)
biomass The total living mass in a
defined segment of an ecosystem expressed as the living weight per unit area
or mass. Soil microbial biomass is often used as an indication of potential
microbial activity level in soil.
biometer flask Experimental apparatus
commonly used in laboratory studies of pesticide degradation in soil. Contains
separate compartments for aerobic incubation of soil and for media to trap
carbon dioxide and volatile products.
biopesticide Pesticide of biological origin
including microorganisms e.g. Bacillus thuringiensis and natural products
e.g. rotenone, pyrethrins.
biotransformation Conversion
of the chemical structure of a pesticide catalysed by enzymes in
vitro or in vivo. See also biodegradation.
biotransformation pathway
Sequence of the changes occurring in the structure of a pesticide when
it is introduced into a specific biological test system.
blank material (sample) Laboratory simulated
test material known to be free of the pesticide being analysed. A portion
of blank material is used to test the method, apparatus and reagents for interferences
or contamination. See also control sample. (after Thompson and Wood, 1995)
bound residue Chemical species in soil,
plant or animal tissue originating from a pesticide, (generally radio labelled)
that are unextracted by a standard method, such as Soxhlet solvent extraction,
which does not significantly change the chemical nature of the residues. These
unextractable residues are considered to exclude small fragments recycled
through metabolic pathways into natural products. (after Roberts, 1984)
breakdown See degradation.
buffer zone Distance for environmental
protection between the edge of an area where pesticide application is permitted
and a sensitive non-target area e.g. water course.
> Synopsis
> Preface
> References
