D10: Impact of Contaminants - Hydromod

Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas
EUROLAKES
D10: Impact of Contaminants
FP5_Contract No.: EVK1-CT1999-00004
Version: 4.0
Date: 25/07/01
File: D10-vers.4.0.doc
Page 30 of 136
A potential solution should be to incorporate a procedure to identify the relevance of
endocrine alterations. e.g. using the data produced on mammals. This hazard identification
will be useful to select those tests which can produce the adequate response,
e.g. to define which chronic toxicity tests on fish is required. This information should
also be very useful for the assessment of secondary poisoning, this part is described as
provisional in the current EU protocol for ecological risk assessment and although the
potential for bioaccumulation is obviously included, additional efforts should be allocated
for a better understanding of the risk related to the bioaccumulation potential of
persistent chemicals and particularly for an appropriate characterisation of the potential
for biomagnification through the food chains. A combination of potential for biomagnification
and effects on reproduction and/or immunological capacity increase in an exponential
way the risk for top predators, as can be clearly observed from the examples
provided in the chapter on wildlife.
Finally, methods for an adequate characterisation of the potential risks of endangered
wildlife requiring protection at the individual (for example Iberian lynx or Iberian imperial
eagle) or population levels should be developed. These methods, to be developed as
specific scenarios for the local risk assessment, should be applied on certain areas, in
addition to the general ecological risk assessment, when endangered species are expected
to be at risk.
6.2 TESTING STRATEGIES
Scheme 1 displays the current and future options for defining endocrine disrupters. The
studies required for a particular agent will be influenced by the extent of any existing
toxicity database for it. The various screening assays available for use in each tier have
been discussed above.
The sequence of conducting tests and the point of entry into Scheme 1 will be influenced
by many factors. At one extreme, an agent may have been adequately evaluated
for reproductive effects, e.g. in a one- or two-generation study. In such cases, it may be
possible to classify the agent as inactive as an endocrine disrupter, irrespective of any
activities it may be shown to have in in vitro assays. At the other extreme, it may be important
to study analogues of a confirmed endocrine disrupter in order to prioritise analogues
for testing in vivo or to eliminate similarly active members of the chemical class.
In such situations, structure-activity relationship (SAR) or in vitro assays may prove
valuable in cases where the mechanism of action of the lead chemical is known and
where appropriate in vitro assays responsive to it are established. In most cases, however,
a single agent with few toxicity data available on it, will be under consideration. In
these cases, four possible testing strategies are possible (A-D, Scheme 1):