Plasma levels of Na+, K+ and Ca2+ were evaluated in fish exposed / not exposed to sublethal concentrations
of Cu to assess adverse effects on osmoregulation as well as their ability to reverse these levels. Acute toxicity tests were performed using barbells (Luciobarbus bocagei) under two different concentrations of Cu. Barbells exposed to Cu showed ionic imbalance, respiratory difficulties, mortality and reduced value of K. According to the results, plasma levels of K+ and Ca2+ increase, while plasma levels of Na+ decrease, allowing the fish an osmotic adjustment and a reduction in susceptibility to Cu.
Under the conditions of this experiment, fish also showed the ability to reverse electrolyte levels when they are no longer exposed to Cu; however, dependent on exposure concentration.
