Human health risk assessment of potentially toxic elements and microplastics accumulation in products from the Danube River Basin fish market.

The present study aimed to quantify the concentration levels of potentially toxic elements (PTEs) such as aluminum, arsenic, cadmium, chromium, copper, nickel, lead, zinc, and mercury, as well as microplastics occurrence in various tissues of fish and seafood species, commercialized in the Lower Danube River Basin. A health risk assessment analysis was performed based on the PTEs concentration levels in the muscle tissue. Estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TR) of PTEs were calculated. It was observed that the species within the seafood category registered the highest levels of PTEs. For instance, in the muscle tissue of bivalve Mytilus galloprovincialis (from the Black Sea), the highest value was observed in the case of Zn (37.693 mg/kg), and the presence of polystyrene polymer was identified. The values associated with EDI, THQ, HI, and TR of PTE exposure were significantly lower than 1.

Preliminary investigation of lower Danube pollution caused by potentially toxic metals.

The current study aims to assess the pollution status of the European river-sea system lower Danube River-Danube Delta-North West Black Sea, through an integrated analysis of metal concentrations in water, sediments and fish community. The Danube flows through numerous industrial cities and receives a significant amount of pollutants due to the reception of urban and industrial emissaries, as well as agricultural land runoff. Samples of water, sediments and fish (10 species) were collected from 7 representative sites along Danube River, Danube Delta and Black Sea shore. For the analysed fish species, potentially toxic and essential elements (Pb, Cd, As, Cu, Fe, Zn, Mg, Ca, Na, K) from muscle and liver samples were measured and discussed. Measurement of elements and other environmental quality parameters were determined for water and sediments. The Black Sea area, represented by S6 and S7, received sediments from Danube with the lowest concentrations of Cd (0.05 ± 0.01 µg g-1, respectively 0.01 ± 0.001 µg g-1), Pb (3 ± 0.03 µg g-1, respectively 2 ± 0.03 µg g-1), As (2 ± 0.02 µg g-1, respectively 1.4 ± 0.3 µg g-1), Ni (8.9 ± 0.1 µg g-1, respectively 5.2 ± 0.2 µg g-1), Cr (8 ± 0.7 µg g-1, respectively 5 ± 0.2 µg g-1), Cu (3 ± 0.1 µg g-1, respectively 2 ± 0.04 µg g-1), Fe(6 ± 0.3 µg g-1, respectively 3 ± 0.1 µg g-1) and Zn (0.03 ± 0.003 µg g-1, respectively 0.017 ± 0.001 µg g-1). These results suggest that the Danube Delta system plays an important role in filtering the pollutants. Based on the biota and water analysis, there was no correlation observed between Cd, respectively Pb concentration in the environment and fish body (Person Coef. = -0.02 in muscle tissue and -0.01 in liver tissue, respectively Pearson Coeff. = -0.06 in muscle tissue and 0.1 in liver tissue). Cadmium remained an active element in the pollution of the Danube area (S1 and S2), with high concentration in the water matrix (0.14 ± 0.02 µg L-1, respectively 0.05 ± 0.01 µg L-1) and fish muscle (0.15 ± 0.03 µg g-1f.w. in C. carpio - S2). This fact was confirmed by several other studies.