Heavy metals are among the most persistent and bioaccumulative pollutants in marine ecosystems, posing significant toxicological threats to fish via complex molecular and cellular disruptions. This review synthesizes current knowledge on the cascade of mechanistic responses in marine fish following HM exposure, which includes oxidative stress, modulation of antioxidant responses, activation of detoxification systems, DNA damage, inflammation, apoptosis, neuroendocrine disruption, and ultimately, cellular energy imbalance. In addition to established pathways, the review highlights recent advances in mechanistic understanding and biomarker development, including cellular stress responses, epigenetic regulation, metal homeostasis mechanisms, and novel molecular indicators. These mechanisms support the development of an integrated biomarker framework that combines classical indicators (e.g., antioxidant enzymes, metallothionein) with next-generation endpoints (e.g., miRNA profiles, gene-level responses of metal transporters or stress chaperones, epigenetic alterations). The interpretation of biomarker responses requires consideration of the exposure context, environmental variables, and physiological status to ensure accurate assessment of sublethal toxicity in field settings. By bridging mechanistic understanding with biomonitoring relevance, this review provides a comprehensive foundation for advancing molecular tools in pollution monitoring and risk assessment. Special emphasis is placed on biomarkers specific to heavy metal exposure, enhancing their diagnostic value relative to general stress indicators.

This study provides a comprehensive evaluation of contamination levels in the Romanian Black Sea within the framework of the Marine Strategy Framework Directive (MSFD). Over the course of five oceanographic expeditions between 2020 and 2022, data were gathered from 70 stations in transitional, coastal, shelf, and offshore waters of the Black Sea. Analyses were conducted on water, sediment, and biota samples for key contaminants: heavy metals (HMs), polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs) such as organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs). The assessment identified contamination hotspots near riverine inputs, urban runoff, harbor activities, and industrial discharges. Offshore waters also showed measurable pollutant levels, likely from diffuse sources and atmospheric deposition. The key findings reveal the widespread contamination of HMs, PAHs, and POPs across the Romanian Black Sea, with concentrations in certain areas exceeding acceptable environmental thresholds, highlighting ongoing challenges for regional pollution management. PAHs were prevalent in both nearshore and offshore regions, while OCPs and PCBs were detected across various matrices, with significant concentrations observed in water and biota samples. The study emphasizes the importance of integrated assessments within the MSFD framework, suggesting that future evaluations should complement the “one out-all out” (OOAO) approach with multi-metric tools, to enhance the robustness of pollution status reporting. Despite improvements in some areas, contamination remains a critical challenge, requiring strengthened regulations, improved waste management, and increased regional cooperation to mitigate the ongoing risks to marine ecosystems. The findings provide valuable data for the upcoming national MSFD assessment cycle (2018–2023) and highlight the need for sustained monitoring and coordinated efforts to ensure long-term marine sustainability.

This study presents an extensive evaluation of the contamination levels in fish, mollusks, water, and sediments in the Black Sea over eight years, from 2016 to 2023. The primary aim was to determine the concentrations and distribution patterns of heavy metals (HMs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and other persistent organic pollutants (POPs) in fish, water, and sediments of the Black Sea, and their implications for marine ecosystem health and human safety. Data were collected through scientific cruises and the methodology involved systematic sampling across different regions of the Romanian Black Sea, followed by rigorous laboratory analyses to identify and quantify the presence of contaminants. The study also examined the temporal trends of these pollutants, providing insights into their sources, pathways, and persistence in the marine environment. Additionally, the research assessed the bioaccumulation of contaminants in various biota, offering a critical perspective on food safety and potential risks to human consumers. The findings revealed significant spatial insights, highlighting areas of concern that require immediate attention and action. Notably, industrial discharge, agricultural runoff, and historical pollution hotspots were identified as major sources of contamination. This research underscores the need for enhanced monitoring and regulatory frameworks to mitigate pollution sources and safeguard the Black Sea ecosystem, advocating for sustainable practices and effective management strategies to preserve marine resources in the Black Sea.

Keywords: contamination; bioaccumulation; fish and mollusks tissue; ecosystem components; heavy metals; organochlorine pesticides; polychlorinated biphenyls; polycyclic aromatic hydrocarbons.

The health of aquatic organisms can be affected due to anthropogenic activities and limited actions to reduce the pollution of the Black Sea. The accumulation of organic pollutants (OPs) in the aquatic environment occurs in water, sediment, and then biota. The turbot (Scophthalmus maeoticus) is a benthic fish of commercial interest scarcely studied in the Black Sea region, and none of the studies researched OP concentrations in its main tissues. In this paper, polycyclic aromatic hydrocarbons (PAHs) and POPs, organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were determined in water, sediment, and turbot muscles, gills, gonads, and livers, to research their accumulation level. The determinations were made with gas chromatography on turbots sampled in 2021 from the Romanian Black Sea waters. OCPs—p,p’DDT and its metabolites p,p’DDE, p,p’DDD—are dominant in the turbot tissues. From PAHs, benzo(g,h, i)perylene was the dominant compound, while for PCBs it was PCB 52. The OPs’ presence in the wild turbot is due to river input, dredging and coastal rehabilitation works, industrial activities and contaminated food and poses a risk to human health due to the exceeding maximum allowable concentration for human consumption in Romania and the European Union.