Environment
Study points to thallium pollution in the Baltic Sea
According to a study, the Baltic Sea is relatively heavily contaminated with the toxic heavy metal thallium. photo
© Frank Hormann/dpa
The Baltic Sea is an ecologically highly sensitive inland sea. Discharges and pollution can have serious consequences for flora and fauna. Researchers warn about the dangers of thallium.
In a study, scientists found a relatively high level of pollution Baltic Sea with the toxic heavy metal thallium. Human activities are responsible for a significant portion of thallium emissions over the past 80 years, ranging from 20 to over 60 percent, according to a study by researchers from the Woods Hole Oceanographic Institution (WHOI) in the US state of Massachusetts and others Facilities in Bremen and Rostock, among others.
Several media outlets had already reported on the study recently published in the specialist magazine “Environmental Science & Technology”. Thallium (element symbol: TI) is considered highly toxic to mammals. The proportion of TI in the water of the Baltic Sea currently remains low. However, the value could increase and this could also be due to a sometimes intentional natural or human-induced increase in the oxygen content in the Baltic Sea.
The data strengthens evidence that the release of thallium in seawater and sediments depends largely on the absence of oxygen and the presence of sulfides, said co-author Colleen Hansel from WHOI’s Division of Marine Chemistry and Geochemistry. Thallium is bound by sulfides in the sediment. However, an increase in oxygen reduced the sulfides.
The analysis of sediment cores reportedly showed that enrichment with TI began around 1940 and 1947. Even if the origin cannot yet be traced exactly, the study points to regional cement production, which was ramped up after the Second World War, as a source of entry. The Max Planck Institute for Marine Microbiology in Bremen and the Leibniz Institute for Baltic Sea Research Warnemünde (IOW) were also involved in the study.