| dc.description.abstract | The presence of persistent contaminants in the sediments, such as heavy metals and
hydrocarbons, can have long-lasting negative effects on marine ecosystems, resulting in harming
both wildlife and humanity. It is critical to rehabilitate the impacted habitats and prevent future
contamination for our own good. Such an example is the Port of Liepāja from Latvia, where high
levels of pollutants were identified more than two decades ago. Since then many efforts have
been made to improve the ecological status of the channel, following a complex strategy of
multiple cleaning procedures to ameliorate the negative impact over the Baltic Sea and to exclude
the Port of Liepāja from the Red List of ”collapsing biotopes” (HELCOM 2013).
The current study aimed to assess the environmental hazard of persistent contaminants
and trace the effects of the environmental measures undertaken over time in the Karosta Channel - Liepaja, Latvia. The most recent and consistent dredging activities had the purpose of removing
the majority of the remaining polluted sediments from the channel. This created an ideal moment
for evaluating the immediate environmental impact of the dredging as such and calculating the
rate of ecosystems' regeneration in the near future. Moreover, by analyzing the content of
hydrocarbons and heavy metals in the residual sediments, the study provided more information
on how successful the ecological cleanup was.
The critical evaluation of the methods applied within this project provided a different
perspective over the theorized remediation procedures, thus developing knowledge in this aspect.
The results of the study revealed that hydrocarbons and heavy metal pollutants cannot be easily
removed from coastal marine habitats. Dredging activities, in the absence of the complementary
procedure of “capping”, increased the levels of detected pollutants in the remaining sediments
and surface water. By disturbing the old deposits of contaminated sediments, the cleaning
procedure had a negative impact on the habitat, worsening the overall pollution status. In the end,
it was concluded that such actions provide the opportunity for a better ecological state in the near
future if certain measures are taken.
This project will contribute to the existing knowledge of cleaning techniques in the
coastal zones, emphasizing sediments and other particulate-bound contaminants, by applying new
technologies and learned methods. | |