Pesticide Degradation in Water - Pesticides: Evaluation of Environmental Pollution - page 94

and chronic toxicity and to achieve good ecological status and healthy ecosystems. The
Commission will propose a list of priority substances that shall be prioritized for action
on the basis of risk to or via the aquatic environment and will set environmental quality
standards for these substances. The prioritization will be based on a risk assessment car-
ried out, following the relevant Community legislation regarding hazardous substances
or relevant international agreements, particularly under Council Directive 91/414/EEC
for assessment of pesticides, and Member States may need to ensure that additional
pollutants of national relevance are controlled. The list has to be reviewed from time to
time, and it was last amended by Directive 2008/105/EC (European Commission 2008).
In this case, different environmental quality standards can be set for every pesticide in
surface water. The situation is quite different for pesticides in groundwater, in which a
general quality standard is set.
The WFD also sets a common approach for monitoring water quality across all
Member States but does not specify the methods to be used. It is up to the Member
States to decide the best method based on local conditions and existing national
approaches. Where pesticide controls include a review of the relevant authorizations
issued under Directive 91/414/EEC, such reviews shall be carried out in accordance
with the provisions of this Directive.
The risk assessment conducted in the framework of directive 91/414/EEC (European
Commission 1991) at EU level for the authorization of plant protection products is
aimed to guarantee that the residues, generated when good agricultural practices
(GAPs) are used, have no hazard for human or animal health and for groundwater and
the environment. Since its publication, this directive has been repeatedly amended. In
particular, Directive 95/36/EC (European Commission 1995) develops data require-
ments in relation to the fate and behavior in the environment; Directive 96/12/EC
(European Commission 1996) develops data requirements in relation to the ecotoxico-
logical behavior; and Directive 97/57/EC (European Commission 1997) lays down the
Uniform Principles for the evaluation. In the frame of these directives, different guid-
ance documents have been developed in order to harmonize the evaluation process.
The identification of relevant metabolites is one of the tasks to be considered in the risk
assessment. It is important to point out that, within the evaluation, a residue definition
is set for the risk assessment, but for monitoring purpose, the residue definition can be
simpler for a practical enforcement.
4.4.2 Other International Legislation
All over the world, national governments have established guidelines and residue limits
for environmental waters (groundwater and surface waters), although most attention has
been given to the set of limits for drinking water. The World Health Organization (WHO)
published International Standards for Drinking Water from 1958 to 1982, when it started
the publication of Guidelines for Drinking-Water Quality (WHO 2010). The guidelines are
based on a system called “Water Safety Plans” that integrate risk assessment and risk man-
agement and allow the establishment of particular national standards and regulations in
each country. WHO uses a different approach than the EU legislation and it set guideline
values for a large number of individual pesticides in drinking water.
The International Union of Pure and Applied Chemistry (IUPAC) has also published
“recommendations” for the establishment of regulatory limits for pesticide residues
in water (Hamilton et al. 2003). This IUPAC technical report also gives an overview of
the water legislation in different countries. In some cases, the residue limit in water is