Trace elements in two endemic fish species (Barbus strumicae, Karaman, 1955 and Squalius оrpheus, Kottelat & Economidis, 2006) of Nestos River (NE Greece): levels, organ bioaccumulation and potential health risk

Abstract

Abstract This paper aims to determine the content of eight trace elements (Li, Cr, Co, As, Se, Cd, Pb and Hg) and one radioisotope (238U) in kidney, liver and muscle tissues of two endemic species (Squalius orpheus and Barbus strumicae) from Nestos River (northern Greece), and to evaluate the potential risk to human health due to the consumption of the edible part of the fish. An attempt to distinguish potential differences in bioaccumulation patterns between the examined species and sites was also done. Higher concentrations of all elements were found in kidney and liver tissues for both species, except Hg. The site closer to the river-mouth presented higher concentrations since it receives point and non-point effluents from agricultural activities. On the other hand, an irrigation dam operating close to the upstream station obstructs the free transportation of sediments and suspended matter downstream. As a result, this site is characterized by lower element concentrations. Feeding habits are a significant factor for the metal accumulation in fish; the sediment inhabitant and feeder B. strumicae showed elevated concentrations compared to the water column resident S. orpheus. According to MDI, THQ and TTHQ values calculated for both species, the element bioaccumulation is negligible and the consumption of the fish edible tissue by humans for both species poses zero health risk in developing chronic undesired effects.