Heavy metals are of particular concern due to their toxicity and bioaccumulation ability in aquatic ecosystems and aquatic organisms. In general, they are not biodegradable and have long biological halflives. According to the World Health Organization (WHO), heavy metals must be controlled in food sources in order to assure public safety [1]. Heavy metals are taken up and accumulated by aquatic organisms both from the surrounding medium and via food sources (deep-sea carnivorous fish in particular accumulate metals in their muscles via the food chain). The extent of heavy metal accumulation is affected by external (dissolved metals, physicochemistry, dissolved oxygen, interactions between metals, sediment, food, seasonal effects, geographical differences) and internal (individual variability, body size and development stage, sex, breeding condition, brooding, moulting and growth, behaviour) factors [2,3].Many species of marine benthic fish are largely being used to assess the quality of aquatic environments because they could concentrate large amounts of some metals in different tissues such as muscle and gills [4,5]. The gills are considered the main site of entry for the dissolved metals. They are sensitive to any change of water components and serve as a good indicator of water quality since gill filaments and lamellae provide a very large surface area for direct and continuous contact with contaminants Pol. J. Environ. Stud. Vol. 24, No. 4 (2015), 1743-1748 AbstractIn the present study, the concentration of cadmium (Cd), lead (Pb), copper (Cu), zinc (Zn), and iron (Fe) in the gill and muscle tissues of four benthic fish species (Merluccius merluccius, Lophius budegassa, Helicolenus dactylopterus, and Chlorophthalmus agassizi) from the northeastern Mediterranean Sea in Turkey were investigated. From the obtained results, the heavy metal concentrations in muscle were lowest and highest in the gills for each species. Cd was not detected in any tissues of the species. The order of heavy metal concentrations were found as Zn>Fe>Cu>Pb=Cd in muscle tissue samples for four selected fish species (p<0.05). In the muscle tissue, the highest concentration of Zn (5.875 μg/g) was found in Lophius budegassa. The concentrations of heavy metals in gills of four selected fish species were Fe>Zn>Cu>Pb>Cd (p<0.05). In the gills, the highest concentration of Fe (73.730 μg/g) was also found in Lophius budegassa. The comparison of our results with previous studies showed that the metal levels of tissues are variable in organisms caught from the same area. In our study, the concentrations of Cd, Pb, Cu, Zn, and Fe in the muscle tissue are less than the permissible limits set for heavy metals by food regulations.

This study was carried out in Adıyaman downtown and its districts in order to determine the current situation of aquarium fish sales places and their problems and offer some solutions. The study was conducted on total of 10 aquarium fish sales places. In the study, face to face interview method and questionnaire were used for the data collection including a total of 25 open and closed-ended questions. In the study, it was determined that 50% of the aquarium fish sales places are located in Adıyaman downtown, 20% in Kahta district, 20% in Besni district and 10% in Gölbaşı district. In the study, it was determined that 90% of the fish that sold were supplied from wholesalers, especially from Gaziantep, Adana, Hatay, Antalya and İzmir. Besides, it was determined that an average of 7000 fish were sold annually. It has been determined that 70% of sellers are not satisfied with their aquarium fish sales, especially during the pandemic period and the sales are negatively affected It was determined that the main problem in this region was fish deaths during transporting.