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MARINE RISK ASSESSMENT
Derivation of the PNECoral values
In the derivation of the PNECoral values only toxicity studies reporting on dietary and oral
exposure are relevant as the pathway for secondary poisoning refers exclusively to the uptake of
chemicals through the food chain. However, reliable toxicity data for predatory marine birds
(such as gulls and penguins) and mammals (such as seals, dolphins, whales and polar bears) are
extremely limited (Nendza et al., 1997). Furthermore, testing of such species would be ethically
unsound and contrary to animal welfare concerns. Therefore, it is necessary to extrapolate
threshold levels for marine species from terrestrial species assuming there are interspecies
correlations between laboratory bird species and marine predatory bird species, and between
laboratory mammals (e.g. rats) and the considerably larger marine predatory mammals. This
procedure is identical to that applicable for other media (see Section 3.8.3.5).
4.3.3.3 Testing strategy
If the PEC/PNEC ratio based on use of default BMF values indicates potential problems at any
trophic level it should first be considered whether a refinement of the PEC-assessment is
possible, i.e. the release and exposure assessment, including the fate related parameters such as
determination of log Kow or BCF. In special cases it may even be considered to start with
bioaccumulation studies in fish to determine the assimilation coefficient and the biological halflife
of the substance (i.e. to determine BMF1) prior to estimating or determining the
bioconcentration factor (BCF). Also a refinement of the PNECoral could be considered, i.e. to
require a long-term feeding study with laboratory mammals or birds to derive a more realistic
NOECoral value. In conducting such a study according to current test methods, it may in special
cases be considered whether to extend such studies to include satellite groups for determination
of the concentration of the substance in the animals during exposure (i.e. to measure
BMF2 values). Alternatively or supplementary to actual testing can be monitoring of biota for
which it is clear that they have lived in the environment that is covered in the assessment. Of
course no active sampling of (top)predators should be performed, but for instance animals that
are found dead can be used to get an indication about possible biomagnification factors in
wildlife. Useful information might also be obtained from eggs or from biopsies of skin or
blubber of marine birds or mammals.
4.4 PBT ASSESSMENT
4.4.1 Introduction
The PBT assessment is considered to be different from the local and regional assessment
approaches, as it seeks to protect ecosystems where the risks are more difficult to estimate.
These additional concerns for the marine environment, which may not be adequately addressed
by the traditional risk assessment methodologies, can be summarised as:
a. the concern that hazardous substances may accumulate in parts of the marine environment
and that:
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(i) the effects of such accumulation are unpredictable in the long-term;
(ii) that such accumulation would be practically difficult to reverse;