# Heavy Metal Bioaccumulation in European Eels (Anguilla anguilla) from the Odra and Vistula River Basins (Poland): Implications for Environmental and Food Safety

## TL;DR

European eels from two Polish rivers were studied to assess heavy metal accumulation in their tissues, showing differences between locations but no health risks for human consumption.

## Contribution

The study introduces a detailed comparative analysis of heavy metal accumulation in European eel tissues from two distinct Polish river basins using statistical methods like PCA.

## Key findings

- Significant differences in heavy metal concentrations were found between eel tissues and between the two river basins.
- Heavy metal levels in eel tissues did not exceed safe limits for human consumption.
- Statistical methods revealed relationships between metal concentrations and environmental factors.

## Abstract

Fish living in polluted waters can absorb harmful heavy metals, which may later be passed on to people through food. For this reason, checking the levels of heavy metals in edible fish is important for both environmental protection and human health. The European eel (Anguilla anguilla) is especially suitable for such studies because it has a long lifespan and easily accumulates pollutants in its body. In this study, the content of mercury, lead, arsenic, and cadmium in different tissues (muscles, liver, gonads, gills) of European eels collected from two inland water bodies in Poland was examined. Clear differences in metal levels were observed between organs and between the two locations. It was found that the concentration of the tested heavy metals did not exceed the safe limits for human consumption of fish. These results show that the European eel can help assess water pollution and support the evaluation of potential health risks related to fish consumption.

The accumulation of heavy metals in fish tissues is widely recognized as an indicator of aquatic environmental pollution, and the analysis of their content provides a basis for assessing ecological risk and the safety of aquatic food. The European eel (Anguilla anguilla) is a species frequently used as a bioindicator in environmental studies due to its wide geographic distribution, long life cycle, and high capacity for bioaccumulation of heavy metals in various tissues. The aim of this study was to assess the variation in the accumulation of heavy metals, i.e., mercury (Hg), lead (Pb), arsenic (As), and cadmium (Cd), in the tissues (muscle, liver, gonads, and gills) of European eels caught in two locations in Polish inland waters. The obtained results showed significant differences both in the concentration levels of individual elements and in their co-occurrence in the examined tissues. The statistical methods used, including correlation analysis, heat maps, and principal component analysis (PCA), allowed for a comprehensive assessment of the relationships between metals and the identification of factors differentiating the studied populations. The obtained results clearly indicate that fish residing in similar environments for long periods exhibit significant differences in heavy metal content in various fish tissues. Fish obtained from environments with potentially higher levels of heavy metal inputs, such as the Oder River EMU compared with the Vistula River EMU, showed higher levels of heavy metal accumulation in tissues. This study also found that the concentration of heavy metals tested did not exceed the safe standards for human fish consumption.