Bioaccumulation of arsenic, chrome, manganese and nickel in the gills of sea trout (Salmo trutta m. trutta L.) from the southern Baltic Sea (Central Pomeranian Region)

This study aimed to assess the concentrations of arsenic (As), chrome (Cr), manganese (Mn), and nickel (Ni) in the gills of the sea trout (Salmo trutta m. trutta L.) collected in the Baltic Sea (northern region of Poland). The results were then compared to permissible limits to detect whether the metal contamination levels in sea trout from the Baltic sea exceed the values of limits admissible. Frequently consumed sea trout (25 samples) were purchased from local fisherman in January-February 2014, from Ustka (54°34'43''N 16°52'09''E), Pomeranian voivodship, Poland. The element contents in the gills were analyzed using an inductively coupled plasma mass spectrometry (ICP-MS) technique. Metal contents in fish samples were found 0.00313- 0.02069 mg∙kg-1 for As (the mean value was 0.01294±0.0009 mg∙kg-1), 0.0118-0.02161 mg∙kg-1 for Cr (0.01449±0.0003 mg∙kg-1), 0.01895-0.14216 mg∙kg-1 for Mn (0.04137±0.0046 mg∙kg-1), 0.00664-0.01528 mg∙kg-1 for Ni (0.00811±0.00034 mg∙kg-1). According to these data, the ranking order of the mean concentration of the heavy metals in fish gills was Mn (0.04137 mg∙kg-1) ˃ As (0.01294 mg∙kg-1) ˃ Cr (0.01449 mg∙kg-1) ˃ Ni (0.00811 mg∙kg-1). The mean concentration of arsenic in gill samples (0.01294±0.0009 mg∙kg-1) was much below the permissible limit of USFDA (1993b) and FAO/WHO (1976). The mean Cr content in the gill of sea trout samples was well within the toxic limit of USFDA (1993a). The samples had lower Cr concentration as compared to the limits of 0.200 set by FSANZ (2002) and 0.100 by EUROPA (2004). Our study reported that the accumulation of Mn was exceeding the maximum permissible limit (by 8.27-16.55-fold) according to WHO/EPA standard (0.0025-0.005 mg∙kg-1) (FAO/WHO 1976). The proposed limit of Ni concentrations in marine fish species as recorded by FAO (1983) is about 10 μg/g and 0.5-0.6 μg/g according to WHO Guidelines for drinking water quality (1985). In general, it can be seen that the concentrations of Ni found in gills of the sea trout in this study are still considered as those of uncontaminated fish. In conclusion, the assessment of element contents in the organs of the sea trout appears to be a useful biomarker to evaluate the toxic effects of heavy metal pollution as well as for human consumption.