Bioaccumulation of copper nanoparticle in gill, liver, intestine and muscle of Siberian sturgeon (Acipenser baerii) juvenile

Copper (Cu) is an essential element required by all living organisms, since at least ۳۰ enzymes are known to use Cu as a cofactor. Cu is also toxic in excess and liver and gills are known to be target organs for it. In the present study, ۲۴۰ Siberian sturgeon juvenile (with initial weight ۲۹.۲ ± ۳.۱ g and initial length ۲۱.۸ ± ۱.۴ cm) were randomly distributed in ۱۲ fiberglass tanks at ۴ different copper nanoparticle (Cu-NPs) treatments with ۳ replicates. Treatments included control (T۰ = no added Cu-NPs), ۵۰ (T۵۰), ۱۰۰ (T۱۰۰), ۲۰۰ (T۲۰۰) µg.l-۱ Cu-NPs (mean primary particle size of ۲ - ۶ nm) in a semi-static waterborne exposure regime. Water exchanged were ۲۰% daily with re-dosing after each change. The experimental period lasted ۲۸ days, ۱۴ days exposure to Cu-NPs and ۱۴ days as recovery time. Fish liver, gill, intestine and muscle were sampled at days ۰, ۷, ۱۴, ۲۱ and ۲۸. Samples were weighed, dried (۱۰۰ ◦C for ۴۸ h) then digested in concentrated nitric acid in a water bath, cooled, and analyzed for Cu concentration in the tissues with graphite furnace atomic absorption spectroscope. Most of the Cu-NPs were accumulated in the intestine, gill, liver and muscle. The accumulation of NPs in tissues was increased in all treatments from day ۷ through ۱۴. In the recovery period, Cu-NPs in tissues decreased but it was still higher than the control treatment. The current findings indicate that preventing the entry of Cu-NPs into the aquatic environment would seem to be essential.

Keywords:

FISH , Nanoparticles , Copper accumulation , Atomic absorption