Trace metals, DOM and UV radiation; a deadly combination?
When trace metals (Mn, Zn, Cd, Fe), deriving from human activities i.e. chemical waste, are largely transported by rivers into the coastal environment, they often undergo complex physico-chemical interactions with dissolved organic matter. Scientists in recent years saw that (UV radiation) could modify these interactions and turn them into high-risk pollutants, affecting the microbial food webs in surface fresh waters and in the coastal environment. In identifying the root of the problem, scientists of the COMET project focused on determining the DOM pool and its molecular weight fractions. Their intention was to detect potential trace metal concentrations within those different fractions and what sort of alterations in the DOM-metal complex may be caused once exposed to UV radiation. These complex interactions between metals, dissolved organic matter and solar radiation would be addressed in a diverse range of European aquatic environments. After conducting experimental studies, scientists saw that under different conditions of salinity certain metals like dissolved manganese, zinc, cadmium and iron, react differently. Some of them increase in oxidation and organic matter like manganese and zinc and others like cadmium and iron decrease. Scientists of the project hope that data from the above measurements will be transferred across scientific boundaries to address the fate of these potential pollutants in the estuary and bring awareness of their harmful impact on the biota food chain in coastal areas.
