Heavy metal effects on P, Ca, Mg, and total protein contents in embryonic pleopodal eggs and stage-1 juveniles of freshwater crayfish Astacus leptodactylus (Eschscholtz, 1823)

Authors: UTKU GÜNER

Abstract: To determine the potential biochemical effects of heavy metal pollution on aquatic organisms, pleopodal eggs, and stage-1 juveniles of the freshwater crayfish, Astacus leptodactylus (Eschscholtz, 1823), was exposed to a non-essential (Cd) and an essential (Cu) metal, either singly or in combination. Three different sublethal doses (0.1, 0.5, and 1 ppm) and 1 interaction dose (0.1 ppm Cu + 0.1 ppm Cd) were used to evaluate the accumulation and toxicity. The effects of 2 doses of metals on P, Ca, total protein, and Mg contents in the embryonic pleopodal eggs and in stage-1 juveniles were examined by an autoanalyzer. The same analyses were also performed on recently spawned eggs through the transition to the first juvenile stage (3 weeks). Ten eggs or stage-1 juveniles were sampled during the 3-week period to measure the bioaccumulation of metals. Cd and Cu levels in the eggs and recently spawned eggs were determined by flame atomic absorption spectrophotometer (FAAS). The results showed that both Cd and Cu accumulated in eggs and in stage-1 juveniles. The results also indicated that metal interactions also occurred, which in this case were probably antagonistic. A comparison of the effects of Cd alone with those of Cd+Cu in combination showed that the mixture was more toxic than Cd alone, but not more toxic than Cu alone. Cd also affected the Ca level in the eggs. The level of Mg increased, while the levels of P, Ca, and total protein decreased in pleopodal eggs exposed to different doses of Cu and Cd. All biochemical parameters and protein levels measured were affected by both metals.

Keywords: Crayfish, Cd, Cu, egg, stage-1 juveniles, P, Mg, Ca

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