Toxico-resistance of Baltic amphipod species to heavy metals

Abstract

Benthic organisms are important components of aquatic ecosystems and have been widely used to assess environmental pollution. Being very sensitive to a wide range of toxicants amphipods are often used as test objects in eco-toxicological studies. The aim of this study was to compare toxico-resistance of various Baltic amphipod species to exposure of heavy metals. The acute toxicity (48-h LC50 and 96-h LC50) of cadmium (CdCl2), copper (CuSO4) and zinc (ZnSO4 ⋅ 7H2O) was detected experimentally, using juveniles and adults of brackish water amphipods, Monoporeia affinis, Bathyporeia pilosa, Gammarus tigrinus, Pontogammarus robustoides and the freshwater amphipod Gammarus pulex as test objects. Amphipods were collected in Latvian territorial waters of the Open Baltic Sea, the Gulf of Riga and in a freshwater body (Kalkugrava canal). Sensitivity of native amphipod species was compared to Hyalella azteca (a species widespread in North America; a strain obtained from the Chesapeake Culture Collection, Hayes, VA, U.S.A.). High sensitivity of all tested amphipod species, except M. affinis, to heavy metals was observed. A two-way ANOVA analysis showed significant differences in toxico-resistance of selected test objects (). The highest toxico-resistance was shown by the brackish water amphipod M. affinis (96-h LC50: Cd 5.16 mg/l; Cu 5.68 mg/l; Zn 11.31 mg/l), but the lowest by the freshwater species G. pulex and H. azteca (96-h LC50 for Cd 0.005 and 0.007 mg/l, accordingly). Cadmium was the most toxic from the tested heavy metals, followed by copper and zinc.