Metal bioaccumulation in liver and gills of brown trout (Salmo trutta Linnaeus, 1758) from the Krka River

Zrinka Dragun

Zagreb, October 2017 AQUAMAPMET Project meeting

Reference site: Krka River spring

Contaminated site: Krka River downstream of Knin town

Sampling sites

Sampling seasons

Autumn: October 2015 Spring: May 2016

Metal October 2015 May 2016

River spring Knin River spring Knin

Ag <0.100 <0.100 <0.100 <0.100

Al 2.20±0.11 5.40±0.48 2.72±0.07 2.38±0.63

As 0.130±0.029 0.200±0.028 0.101±0.019 0.145±0.014

Cd 0.010±0.003 0.010±0.004 0.005±0.001 0.005±0.002

Co <0.019 0.196±0.010 <0.019 0.211±0.033

Cs <0.001 <0.001 <0.001 <0.001

Cu <0.4 <0.4 <0.4 <0.4

Fe 0.910±0.370 4.88±0.37 4.04±0.31 5.16±0.85

Mn 0.100±0.008 3.86±0.15 0.031±0.005 2.97±0.26

Mo 0.210±0.004 0.410±0.005 0.378±0.087 0.515±0.032

Rb 0.250±0.003 0.450±0.007 0.260±0.001 0.316±0.019

Se 0.080±0.022 0.100±0.014 <0.059 0.088±0.059

Sr 67.71±0.38 112.8±0.6 85.49±0.17 168.8±13.2

Tl 0.004±0.000 0.005±0.000 0.005±0.000 0.005±0.001

V 0.520±0.011 0.680±0.003 0.482±0.012 0.617±0.044

Zn <7.3 20.41±5.15 11.07±5.02 17.87±1.26

Metal bioaccumulation in organs of brown trout (Salmo trutta)

Preparation of fish organs for analyses: Cytosolic fraction – metabolically available metal fraction Homogenization Centrifugation at 50,000 g

Target organs: Liver – main detoxification organ Gills – direct contact with water

Metal measurement: Digested cytosolic fraction (HNO3, H2O2, at 85 C) High resolution inductively coupled plasma mass spectrometer (HR ICP-MS)

Al Cu Fe

Mn Rb V

Comparable concentrations at both sites

With the exception of Cu, all elements were higher in the water downstream of Knin town

Higher concentrations at contaminated site downstream of Knin town

Ag As Co

Se Sr Zn

With the exception of Ag, all elements were also higher in the water downstream of Knin town

Cd Cs

Mo

Tl

Higher concentrations at reference site at Krka River spring

Cd, Cs and Tl had comparable concentrations in the water Mo was even higher downstream of Knin town

Comparable concentrations at both sites

Cu, Rb, V – same as in liver

Zn – no statistical difference, but trend of slightly higher concentrations downstream of Knin, as in liver

Cu Rb

V Zn

Higher concentrations at contaminated site downstream of Knin town

Mn – higher in the water downstream of Knin, but not in the liver, gills more sensitive

As, Co, Se, Sr – same as in liver

As Co

Mn Se

Sr

Higher concentrations at reference site at Krka River spring

Cd, Cs, Tl – same as in liver

Fe – not observed in liver (instead higher Mo)

Cd Cs

Fe Tl

Slightly increased dissolved metal concentrations at the location downstream of Knin town

Several elements showed increased bioaccumulation at the location downstream of Knin town both in gills and liver of brown trout, which was consistent with the contamination of river water

Several other elements, namely Cd, Cs and Tl, showed increased bioaccumulation both in gills and liver of brown trout at reference site (Krka River spring), which was rather unexpected and could not be associated with the contamination of river water

Additional study reccomendable to investigate possible influence of sediment contamination and dietary intake

Thank you for your attention