Methods for Deriving Pesticide Aquatic Life Criteria - Reviews of Environmental Contamination and Toxicology - page 25

improve upon the best features of prior methodologies (ANZECC and ARMCANZ
2000; USEPA 2003a). The European Union's Technical Guidance Document
(TGD) on Risk Assessment is also emphasized because it represents the latest
European guidance on derivation of predicted no-effect concentrations (PNECs) for
risk assessments, and EU member nations are starting to use the TGD for derivation
of water quality criteria (Traas, 2005, personal communication).
Table 3 lists the six major methodologies commonly employed, the types of
criteria that are derived from them, and how the criteria are used. The USEPA
methodology (1985) utilizes a statistical extrapolation procedure to derive criteria,
while the Canadian methodology (CCME 1999) utilizes an assessment factor (AF)
approach. All of the others utilize a combination of these two basic criteria deriva-
tion methods. Similarities and differences between key elements of the methodolo-
gies identified in Table 3 are summarized in Table 4. As this chapter proceeds, Table
4 should help the reader understand how each element fits into existing criteria
derivation methodologies.

3 Water Quality Policy

Different countries of the world have different environmental policies, which are
reflected in their water quality criteria derivation methodologies. The EU's Water
Framework Directive (WFD) is the policy document guiding water quality protec-
tion efforts for EU member states (EU 2000). The 11th principle of the WFD states
that environmental policy should “…contribute to pursuit of the objectives of pre-
serving, protecting and improving the quality of the environment, in prudent and
rational utilization of natural resources, and to be based on the precautionary prin-
ciple and on the principles that preventive action should be taken, environmental
damage should, as a priority, be rectified at source and that the polluter should pay.”
The precautionary principle may be summed up as follows:

In order to protect the environment, the precautionary approach shall be widely applied by
States according to their capabilities. Where there are threats of serious or irreversible
damage, lack of full scientific certainty shall not be used as a reason for postponing cost-
effective measures to prevent environmental degradation. (Rio Convention 1992)
Applegate (2000) affirms that, while containing many precautionary elements,
US policy does not adhere to the precautionary principle; many other factors (espe-
cially economics) drive US environmental policy. In addition, the USEPA has
embraced the use of ecological risk assessment to assess potential chemical hazards.
Chapman et al. (1998) noted that the precautionary principle undermines the risk
assessment approach by defining either infinitely small no-effect concentrations or
infinitely large safety factors. Although subscribing to the precautionary principle,
EU member countries, Canada, the Netherlands, South Africa, Denmark, and
Australia/New Zealand, have incorporated risk assessment techniques into their
water quality criteria derivation methodologies (Lepper 2002; European Chemical
Bureau, ECB 2003; CCME 1999; RIVM 2001; Roux et al. 1996; Samsoe-Petersen
and Pedersen 1995; ANZECC and ARMCANZ 2000). Thus, although arising from