Mapping differential elemental accumulation in fish tissues: Importance of fish tissue sampling standardization

Abstract

The concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn in the muscle, gills, liver and intestine
of the wels catfish (Silurus glanis) from the Danube River were analyzed by inductively coupled plasma mass spectrometry
(ICP-MS). The aim of the study was to determine whether in complex muscle/skin, gill filament/gill arch, proximal/distal
liver and proximal/median/distal intestine samples, particular components differ in concentrations of the analyzed elements.
Results indicated that there were no differences in the accumulation of different elements between the proximal and distal
liver segments and between the proximal and median intestine sections. Conversely, elemental accumulation patterns in
muscle and skin differed significantly. Significant differences were also observed between the gill arch and filaments, as well
as between the distal and the two upper intestine sections. Findings indicated the importance of detailed reporting of tissue
sampling, i.e. whether the skin was included in the muscle sample, as well as if the gill arch and filaments were analyzed
together. Due to a potential bias that can be produced by different muscle/skin or gill arch/filament ratios included in the
sample, we strongly recommend that they should not be analyzed together. Results of the present study might be of interest
to the scientific community and stakeholders involved in aquatic ecosystem monitoring programs.