Environmental concern due to handling of hazardous chemicals is growing. This issue draws
stakeholder attentions more than before to risks associated with accidental spillage in industry
or traffic. This study aims at addressing the risks resulting from the spillage of one metric
tonne nonylphenol from an imaginary traffic accident.
The environmental risk assessment approach outlined in this study attempts to address the
concern for the potential impact of hazardous substances on the environment by examining
both exposures and effects of such incidents on the structure and function of the ecosystem.
Nonylphenol has been selected as the discharged contaminant in this thesis for these reasons.
It is an organic liquid with low vapour pressure. It is not produced in Sweden. About 2400
tonnes are imported yearly. It is mainly used for making nonylphenol ethoxylates, which have
a wide use as detergents, emulsifiers, lubricants and additives in a variety of industries. It is
released from the ethoxylates in waste water. There are some published reports on its toxicity
as well as endocrine property to species.
In this study the exposure concentrations are predicted through developing a multimedia fateexposure
model for the Göta älv fresh water ecosystem. It is a dynamic version of QMXfugacity
model applicable for river basins. This fate model is integrated with a simplified food
web model in order to quantify the extent of nonylphenol concentration in organisms.
Moreover the dose response correlation derived from the most validated experimental studies
is utilized to estimate Predicted No Effect Concentration for aquatic ecosystem.
The probability of accidental spillage of nonylphenol is extremely low and is not part of this
study. On the other hand the consequence of spillage affecting the ecosystem is treated from
several aspects, mainly by using the PEC/PNEC ratio. In the aquatic ecosystem pelagic (free
water) and benthic (bottom zone) organisms are studied.
Estimated risk concerning the spillage suggests that acute toxicity among pelagic organisms is
plausible up river especially in the Trollhättan region. However sub-lethal effects such as
reproduction and growth inhibition will probably be observed all along the river with most
concern in up river. In the sediment phase the benthic organisms are shown to be put at risk
for a prolonged period of time and organisms may suffer from chronic toxicity. In addition the
sediment acts as a sink for contaminant with potential release of the...
