Pure Appl. Chem., 2003, Vol. 75, No. 8, pp. 1123-1155
http://dx.doi.org/10.1351/pac200375081123
CHEMISTRY AND THE ENVIRONMENT DIVISION
COMMISSION ON AGROCHEMICALS AND THE ENVIRONMENT
Regulatory limits for pesticide residues in water (IUPAC Technical Report)
Abstract:
National governments introduced residue limits and
guideline levels for pesticide residues in water when policies were
implemented to minimize the contamination of ground and surface waters.
Initially, the main attention was given to drinking water.
Regulatory limits for pesticide residues in waters should have the
following characteristics: definition of the type of water, definition
of the residue, a suitable analytical method for the residues, and explanation
for the basis for each limit.
Limits may be derived by applying a safety factor to a no-effect-level,
or from levels occurring when good practices are followed and also passing
a safety assessment, or from the detection limit of an analytical method,
or directly by legislative decision.
The basis for limits and guideline values issued by WHO, Australia,
the United States, New Zealand, Japan, Canada, European Union, and Taiwan
is described, and examples of the limits are provided. Limits have been
most commonly developed for drinking water, but values have also been
proposed for environmental waters, effluent waters, irrigation waters,
and livestock drinking waters. The contamination of ground water is
of concern because it may be used as drinking water and act as a source
of contamination for surface waters. Most commonly, drinking water standards
have been applied to ground water.
The same terminology may have different meanings in different systems.
For example, guideline value (GV) in WHO means a value calculated from
a toxicology parameter, whereas in Australia, a GV is at or about the
analytical limit of determination or a maximum level that might occur
if good practices are followed. In New Zealand, the GV is the concentration
where aesthetic significance is influenced.
The Australian health value (HV) is conceptually the same as the WHO
GV. The New Zealand maximum acceptable value (MAV) and the Canadian
maximum acceptable concentration (MAC) are also conceptually the same
as the WHO GV.
Each of the possible ways of defining the residues has its merits.
A residue limit in water expressed as the sum of parent and toxicologically
relevant transformation products makes sense where it is derived from
the acceptable daily intake (ADI). For monitoring purposes, where it
is best to keep the residue definition as simple as possible for the
sake of practical enforcement and economy, the
parent or a marker residue is preferable. It is also possible for parent
and degradation products (hydrolysis and photolysis products and metabolites)
to become physically separated as the water moves through soil strata,
which suggests that separate limits should be set for parent and important
degradation products.