The effect of dietary copper exposure to benthic ostracod Heterocypris incongruens using whole sediment toxicity test Utilisation du test de toxicité des sédiments pour l'estimation de l'effet de l'exposition au cuivre alimentaire sur les ostracodes benthiques Heterocypris incongruens

In this study, we investigated the bioaccumulation of copper (Cu) by microgreen algae Scenedesmus acutus and Chlorella vulgaris and toxicity of dietborne copper from algae to benthic ostracod Heterocypris incongruens. Scenedesmus acutus and C. vulgaris were exposed to different concentrations of waterborne Cu for 10 days then the ostracod was fed this food exclusively under 24h dark condition for 6 days, partially modifying the test method recently published as ISO 14371. Total copper in the cells increased with increasing dissolved copper concentrations from 4.8 to 4.5 x 10 μgCu/g dw and 10 to 5.3 x 10 μgCu/g dw for S. acutus and C. vulgaris, respectively. Most of the accumulated Cu were located inside the cells. The Cu-exposed algae increased the mortality of the ostracod. The concentration of dissolved copper in the overlying water at the end of the test was too low to cause the mortality of ostracod, thus the dietborne Cu was most likely the cause. There was almost no difference among the different fractions to determine the possible toxic effect of dietary Cu to ostracod thus, total or trophically available copper can be used to show the dietary Cu effect to ostracod. The dose-response relationship between the dietborne Cu and ostracod mortality would be useful in interpreting the results of ostracod toxicity tests in various applications. To our knowledge, the effect of dietborne Cu to ostracod H. incongruens has not been reported.