Acute Cu toxicity, metal bioaccumulation and ion loss in the Neotropical cyprinodontiform Jenynsia multidentata

Abstract

The acute toxicity of Cu, metal bioaccumulation and ion loss in the cyprinodontiform Jenynsia multidentata , a highly eurihaline Neotropical freshwater fish of wide distribution in the Rio de la Plata basin, was established during a 96 h static exposure. The median lethal concentration at 96 h was 229 µg Cu l -1 . The effect of CuSO 4 5H 2 O was tested in natural freshwater in two-liter Pyrex glass chambers at controlled temperature, with natural light and artificial aeration. During the first hours of exposure to concentrations above 130 µg Cu l -1 , an increase in aquatic surface respiration, air gulping and erratic swimming were observed, showing evidence of the affection of the respiratory system. The concentration of Cu, Na and K in the whole body burden at the end of each experiment showed by correlation analysis Cu bioaccumulation and loss of Na + and K + . The concentration of Cu in water was positively correlated with its bioaccumulation (r=0.79, p=0.06), and negatively correlated with the whole body burden of K + (r=-0.84, p=0.037). K + loss was positively correlated with Na + loss (r=0.88, p=0.02). Cu LC50 for this cyprinodontiform seems rather low when compared to fishes often utilized in toxicity tests