Element concentrations of cultured fish in the Black Sea: selenium-mercury balance and the risk assessments for consumer health

Heavy Metal Biomonitoring in Cultured Rainbow Trout of the Black Sea and Risk Estimations on Its Consumption

In recent years, the growing importance of fish species obtained through aquaculture, coupled with a decline in wild-caught fish, has raised concerns about the potential accumulation of pollutants in these fish. This work aimed to analyze the amounts of elements in trout cultured mainly between Sinop and Samsun shores at the south of the Black Sea and marketed in Sinop fish markets. The comparison of these values with national and internationally accepted regulations was conducted, and evaluation of health risks for consumers was performed. Oncorhynchus mykiss samples were bought in April, May, and June of 2022 and 2023. The heavy metal concentrations were determined using inductively coupled plasma mass spectrometry (ICP-MS). Fish tissues were wet digested in Teflon vessels. The outcomes were contrasted with established regulatory limits for heavy metals in fish. Fortunately, the metal concentrations detected in the fillets were found to be below the permissible levels set by regulations, indicating that the fish were not significantly contaminated. Furthermore, the estimated daily intake (EDI) and target hazard quotient (THQ) values, which are utilized to evaluate the possible health risks connected with heavy metal exposure, were calculated. It was reassuring to find that both EDI and THQ values were below the acceptable thresholds, suggesting that the consumption of O. mykiss is not likely to pose a threat to human health. To preserve seafood safety and safeguard public health, however, constant monitoring of fish metal levels is necessary.

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.

Comparison of selenium levels between diabetic patients with and without retinopathy

Background/Aim: Diabetic retinopathy is a common ailment that causes visual impairment among adults, and evidence suggests that oxidative stress plays a significant role in its pathogenesis. The objective of this study was to examine the potential association between selenium deficiency and an increased risk of diabetic retinopathy among individuals with type 2 diabetes mellitus. Methods: This study was a prospective case-control study. 115 patients with a diagnosis of type 2 diabetes mellitus were included. The patients were divided into groups with and without retinopathy. No subgroups were made according to the level of retinopathy. The aim was to compare the serum selenium level of patients between groups. Therefore, other variables that may contribute to the development of retinopathy were also recorded. The duration of diabetes, medications used, and glycosylated hemoglobin levels were recorded. The retinopathy group included 47 patients, and the non-retinopathy group included 68 patients. Selenium levels were measured in plasma samples. Results: The mean selenium level of the retinopathy group (70.11 [17.28] μg/l) was significantly lower than that of the non-retinopathy group (80.20 [19.10] μg/l) (P=0.005). The median duration of diabetes mellitus was significantly higher in the retinopathy group than in the non-retinopathy group (10 [1-25] and 6 [1-21], respectively; P=0.002). Logistic regression analyses showed that higher levels of blood selenium were independent preventive factors against the occurrence of retinopathy (OR [95% CI]: 0.965 [0.939-0. 991]). The duration of diabetes mellitus was an independent risk factor for retinopathy occurrence [OR (95% CI): 1.131 (1.050-1.219)]. One unit increase in selenium level was associated with a unit decrease in diabetic retinopathy of 0.965 (0.939-0.991). Conclusion: Our research revealed a correlation between the duration of diabetes and the incidence of diabetic retinopathy. Furthermore, a notable difference was observed in blood selenium levels between patients with diabetic retinopathy and those without it. Specifically, patients with diabetic retinopathy had lower plasma selenium levels compared to the control group. These findings have potential implications for the treatment or prevention of diabetic retinopathy, but more research is needed to determine the efficacy of selenium supplementation for diabetic patients with or without microvascular complications. Future studies should investigate the effect of selenium deficiency on different subtypes of diabetic retinopathy and the impact of selenium supplementation in this patient population.