Environmental Engineering Reference
In-Depth Information
compounds were classified as high, medium, low or very low risk. Around 30
active ingredients were classified as high, medium or low risk.
Sinclair et al.(
2006
) described a screening approach for identifying pesticide
degradates that might pose a risk to drinking water supplies. The approach
combines data on pesticide usage, degradate formation, properties and persis-
tence with a simple screening model to determine the potential exposure of
drinking water to different degradates. Exposure estimates are then compared to
Acceptable Daily Intakes for the associated parent pesticide to determine relative
risk. The approach has been applied to the UK and California. Degradates
identified as highest priority in UK drinking water sources are given in
Table 5.4
.
Monitoring of the environment
As ecosystems are so complex, it is probably impossible to predict the impact of
a substance on the actual environment based on laboratory studies and model-
ling alone. The approaches described above should therefore go hand-in-hand
with biological based monitoring programmes in the real environment. For
example, ecological monitoring will provide an indication of the impacts on
structure and functioning of a system. This approach is already employed in
surface water assessment in many countries, but perhaps we should begin to
expand the monitoring to other systems (e.g., soil systems). Monitoring
of biomarker responses might also be appropriate although the link between
biomarker response and ecological functioning is often not clear. In instances
where impacts on an ecosystem are observed, the use of effects directed analysis
may help to identify stressors
both emerged and emerging.
Research needs
It is clear that, over the past few years, there has been increasing interest in the
risks of emerging contaminants in the environment. There are, however, still
many questions that need to be addressed before we can say whether residues
in the environment are a threat to human and environmental health:
1. What are the risks of substances that have yet to be studied? Due to resource
limitations only a small proportion of substances in use today have been
investigated. There is, therefore, a need to develop an understanding of how
other substances will affect the environment and for the further develop-
ment of approaches for identifying substances of most concern.
2. How can we analyse certain emerging contaminants in environmental
media? While there have been significant advances in analytical techno-
logy over the past decade which now allows us to detect many classes of
emerging contaminants at low levels in complex media, for selected con-
taminants (e.g., engineered nanoparticles), method development is still in
its infancy (e.g., Tiede et al.
2008
).
