Assessment of pollution with heavy metals and petroleum products in the sediments of Varna Lake

We present the results from the first large-scale study on pollution in the Varna Lake sediments, which was implemented in two preselected zones with significant importance for developing economic activities and urban planning. Based on 140 probes, we developed a digital map of the pollution gradients in these zones. The sediment analysis shows that the pollution levels at specific locations significantly exceed the international standards for contamination with heavy metals and petroleum products. The reported pollution concentrations can be linked to various contamination sources, such as rivers, ports, the chemical industry, and WWTPs (Waste water treatment plants), located on the shores of the lake. The high values of pollution with iron, copper, and petroleum product registered in the sediments of Lake Varna indicate the need for sustainable management of human activities in the area. The presented findings motivate urgent measures for cleaning and improving the ecological situation in Varna Lake, which is an integral part of the ecosystem of the city of Varna and other municipalities bordering the lake. The results of the study indicate that urgent action is needed to address the high risks associated with the observed sediment contamination.