Decades of Damage: Humans Are Contaminating the Baltic Sea With Toxic Metals

New research by scientists from the Woods Hole Oceanographic Institution (WHOI) and other institutions reveals that human activities have contributed significantly to the presence of toxic thallium in the Baltic Sea, accounting for between 20% and 60% of the total thallium pollution over the last 80 years.

Currently, the amount of thallium (element symbol TI), which is considered the most toxic metal for mammals, remains low in Baltic seawater. However, the research suggests that the amount of thallium could increase due to further anthropogenic, or human-induced, activities, or due to natural or human re-oxygenation of the Baltic that could make the sea less sulfide-rich. Much of the thallium in the Baltic Sea, the largest human-induced hypoxic area on Earth, accumulates in the sediment thanks to abundant sulfide minerals.