Trace metals in flounder, Platichthys flesus (Linnaeus, 1758), and sediments from the Baltic Sea and the Portuguese Atlantic coast

Contaminant levels versus toxicity bioassays in ecological risk assessment of sediments from the southern Baltic Sea

Surface sediments collected in 2021 from six locations in the southern Baltic Sea (Polish district) were examined by chemical and toxicological methods. Chemical analyses included polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and their alkylated derivatives, butyltin compounds and 16 major and trace elements. The toxicity was measured using Ostracodtoxkit F and Microtox. The ecological risk of sediment was estimated by hazard quotient (HQ) calculation. Some PAHs, alkylated PAHs and metals (Zn, Hg, Cd and As) could pose a moderate risk in the sediments from the Gdańsk Deep and in the vicinity of the wrecks, but the risk resulting from the presence of all analyzed compounds was considered high for these sediments. In studies using biotests, sediments from the vicinity of the t/s Franken wreck and the Słupsk Furrow were highly toxic to test organisms. Ostracodtoxkit F, compared to Microtox, appeared a more sensitive test for measured compounds.

Toxic metals in fishes, mussels, and sediments from the Puck Bay in the southern Baltic Sea

BACKGROUND

The environment of the Puck Bay is under strong pressure discharged sewage and brine.

METHODS

Toxic metals (cadmium, lead, mercury, arsenic, bromine) were determined in fishes (flounder and perch), sediments, and mussels.

RESULTS

Toxic metals in flounder and perch from the Puck Bay occurred at varying concentrations: Cd - 0.002-0.004 mg/kg; Pb - 0.011-0.029 mg/kg; Hg - 0.050-0.070 mg/kg; iAs lower than 0.02 mg/kg. The highest concentrations of metals occurred in outer bay sediments: Cd - 0.829 mg/kg dw; Pb - 21.54 mg/kg dw; Hg - 0.305 mg/kg dw; iAs - 0.02 mg/kg dw. Metal concentrations in mussels were at low levels. High Pb content (1.915 mg/kg ww) was only determined in samples collected at the station near the brine outfall.

CONCLUSIONS

Concentrations of toxic metals in the fishes, sediments, and mussels from the Puck Bay indicated that the environment of the bay was in good condition.

Assessment of Fish Quality Based on the Content of Heavy Metals

The aim of this study was to estimate the fish quality in terms of the Cu, Fe, Mn and Zn contents. The research material was the muscle tissue of the fish crucian carp (Carassius carassius Linnaeus, 1758), flounder (Platichthys flesus Linnaeus, 1758), Gilthead seabream (Sparus aurata Linnaeus, 1758), mackerel (Scomber scombrus Linnaeus, 1758), Blue grenadier (Macruronus novaezelandiae Hector, 1871), rainbow trout (Oncorhynchus mykiss Walbaum, 1792), tench (Tinca tinca Linnaeus, 1758), tilapia (Oreochromis niloticus Linnaeus, 1758), Walleye pollock (Gadus chalcogrammus Pallas, 1814) and perch (Perca fluviatilis Linnaeus, 1758.). Heavy metals were determined with the atomic absorption spectrometry method (AAS). Significantly high concentrations of zinc (19.52 mg/kg wet weight), copper (0.77 mg/kg) and iron (6.95 mg/kg) were found in the muscles of crucian carp (p < 0.05) compared to the other fish studied, whereas Walleye pollock had a higher content of manganese (0.266 mg/kg) (p < 0.05). All studied fish species do not pose a threat to humans from these four metals. This was indicated by quality indexes (THQ and HI) whose values were below one. The values of these metals also did not exceed the maximum allowable concentrations established by the FAO (1983), but monitoring both the aquatic environment and the fish living there is necessary, for example, for the time-changing abiotic and biotic factors that can cause an increase in metals in the organs of fish.

Copper and cadmium administration induce toxicity and oxidative stress in the marine flatworm Macrostomum lignano

The contamination of coastal regions with different toxicants, including heavy metal ions such as copper and cadmium jeopardize health and survival of organisms exposed to this habitat. To study the effects of high copper and cadmium concentrations in these marine environments, we used the flatworm Macrostomum lignano as a model. This platyhelminth lives in shallow coastal water and is exposed to high concentrations of all toxicants that accumulate in these sea floors. We could show that both, cadmium and copper show toxicity at higher concentrations, with copper being more toxic than cadmium. At concentrations below acute toxicity, a reduced long-term survival was observed for both metal ions. The effects of sublethal doses comprise reduced physical activities, an increase in ROS levels within the worms, and alterations of the mitochondrial biology. Moreover, cell death events were substantially increased in response to sublethal concentrations of both metal ions and stem cell activity was reduced following exposure to higher cadmium concentrations. Finally, the expression of several genes involved in xenobiotic metabolism was substantially altered by this intervention. Taken together, M. lignano has been identified as a suitable model for marine toxicological studies as it allows to quantify several relevant life-history traits as well as of physiological and behavioral read-outs.

Metals in the Scheldt estuary: From environmental concentrations to bioaccumulation

To investigate the relationship between metal concentrations in abiotic compartments and in aquatic species, sediment, suspended matter and several aquatic species (Polychaeta, Oligochaeta, four crustacean species, three mollusc species and eight fish species) were collected during three seasons at six locations along the Scheldt estuary (the Netherlands-Belgium) and analysed on their metal content (Ag, Cd, Co, Cr, Cu, Ni, Pb, Zn and the metalloid As). Sediment and biota tissue concentrations were significantly influenced by sampling location, but not by season. Measurements of Acid Volatile Sulphides (AVS) concentrations in relation to Simultaneously Extracted Metals (SEM) in the sediment suggested that not all metals in the sediment will be bound to sulphides and some metals might be bioavailable. For all metals but zinc, highest concentrations were measured in invertebrate species; Ag and Ni in periwinkle, Cr, Co and Pb in Oligochaete worms and As, Cd and Cu in crabs and shrimp. Highest concentrations of Zn were measured in the kidney of European smelt. In fish, for most of the metals, the concentrations were highest in liver or kidney and lowest in muscle. For Zn however, highest concentrations were measured in the kidney of European smelt. For less than half of the metals significant correlations between sediment metal concentrations and bioaccumulated concentrations were found (liver/hepatopancreas or whole organism). To calculate the possible human health risk by consumption, average and maximum metal concentrations in the muscle tissues were compared to the minimum risk levels (MRLs). Concentrations of As led to the highest risk potential for all consumable species. Cadmium and Cu posed only a risk when consuming the highest contaminated shrimp and shore crabs. Consuming blue mussel could result in a risk for the metals As, Cd and Cr.

Nutrient and metal pollution of the eastern Gulf of Finland coastline: Sediments, macroalgae, microbiota

The anthropogenic pollution along the coastline of the eastern Gulf of Finland was studied through a range of methods, including analyses of metal contamination in water, surface sediments, accumulated algal biomass and its correlation with resistant microbiota. According to concentrations, the main pollutants in water were copper and manganese. Influence of Nuclear Power Plant was remarkable in adjacent areas and was expressed in high concentrations of molybdenum, nickel, copper and other elements in the water. Relatively high concentrations of copper, lead and zinc were found in sediments. Microbial tolerance appeared to be correlated with the concentration of the metals in sediments. Higher tolerance levels were found in sediment samples from more polluted stations. Macroalgae, which were massively developed in the coastal zone, had shown high level of metal bioaccumulation. Analyses of carbon, nitrogen and phosphorus content of algal tissues allowed the estimation of additional nutrient loading from accumulated decaying algal biomass on the coastal zone of the eastern Gulf of Finland. Mass development of algae in coastal area may contribute to accumulation of organic matter and associated metals. In our study the highest metal concentrations in sediments were found at the sites with dense and continuous layer of fresh and decaying macroalgal biomass, accompanied by hypoxic conditions. Also our study has shown that accumulated biomass may be a significant source of nutrients in the coastal ecosystem.

Assessing the environmental genotoxicity risk in the Baltic Sea: frequencies of nuclear buds in blood erythrocytes of three native fish species

Nuclear bud (NB) formation was investigated in blood erythrocytes of 1892 flounder Platichthys flesus, herring Clupea harengus, and eelpout Zoarces viviparus specimens that were collected at 82 sites representing different regions of the Baltic Sea in 2009-2011. This is the first attempt to evaluate the baseline levels of NB and rank the genotoxicity risk for native fish species. NB levels were compared to the previously published micronuclei (MN) data from the same individual fish specimens in order to compare the two methods of genotoxicity assessment and investigate the relationship between MN as the cytogenetic measure of genotoxicity and the DNA damage reflecting NB. In 2009-2011, elevated NB levels in 89.4% of flounder sampling groups indicated high and extremely high genotoxicity risk levels. Herring and eelpout sampling groups showed elevated levels of NB, 74.6 and 45.7%, respectively. In general, herring and eelpout NB measure was more sensitive as the genotoxicity biomarker than MN.