The present study presents, for the first time, results from comprehensive chemical analyses concerning heavy metals, toxic elements, various polychlorinated diphenyl ethers (PCBs), congeners, polycyclic aromatic hydrocarbons (PAHs), and pesticides in sediments, surface waters, and mussels from the Bulgarian Black Sea. In the samples from most of the investigated locations, iron, zinc, PCB-28, and PAHs (benz(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(ghi)perylene, and chrysene) were detected in the waters; arsenic, copper, iron, and zinc in the sediments; and arsenic, copper, cadmium, iron, lead, zinc, and PAHs (acenaphtene, acenaphthylene, anthracene, bezno(b)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, fluorene, naphthalene, phenanthrene, and pyrene) in the mussels. No pesticides were detected in any of the analyzed matrices. According to Commission Regulation (EU) 2023/915 of 25 April 2023 on the maximum levels for certain contaminants in food and repealing Regulation (EC) No. 1881/2006, there are now human health hazards in terms of consuming bivalve mollusks because the levels of the contaminants that we investigated and are also included in the regulation—Cd, Pb, Hg, ∑PAHs (bezno(a)anthracene, bezno(a)pyrene, bezno(b)fluoranthene, and chrysene)—were less than the maximum permissible levels set by law. The findings suggest that despite the detectable contaminants, the levels in mussels remain below thresholds deemed hazardous to human health. Yet, a set of biomarkers should be assessed in future in order to determine the effects on mussels which seem to live in a chronically contaminated aquatic environment, even though the contaminant levels are lower than the ones set in Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000.

Acknowledgments: This study is financed by the European Union-NextGenerationEU, through the National Recovery and Resilience Plan of the Republic of Bulgaria, project № BG-RRP-2.004-0001-C01.