Biomarker assessment of lanthanum on a freshwater invertebrate, Dreissena polymorpha

tons of oxides in 2003 [3].However, this growing use of REEs is accompanied by enrichment to the environment [4].Indeed, REE senter the groundwater and eventually migrate into rivers and lakes [5] and reach humans through trophic transfer [6,7].Despite their widespread applications, environmental risks related to REEs have received little attention which explains the paucity of data about their bioavailability and ecotoxicological impact.Thus, more research on the environmental impacts and biological effects of REE sis required [8].Lanthanum (La), a representative element of light REEs, is widely used in electronics and optoelectronics, lighters, ceramics, battery [9] and also to stimulate the growth of agricultural products [10].Therefore, this element is considered of specific interest as one of the major lanthanides found in industrial effluents [11].Although dissolved lanthanum species (La3+) represent a very small proportion of lanthanum compounds in water and sediment, they are bioavailable and cause adverse effects in living biological systems [12].In fishes and amphibians, several effects of La have been reported particularly on nervous systems [13,14], excretory organs [15] and smooth muscles [16][17][18].Previous study demonstrated also that La3+ delayed zebra fish embryo and larval development, decreased survival and hatching rates and causes tail malformation in a concentration -dependent way [19].Studies performed with crustaceans are focused mainly in evaluating the effect of La on survival, growth and reproduction [20,21,22] and showed the highest sensitivity of those organisms towards La-ions dissolved from LaCl 3 .In our Knowledge, few reports on La effects in marine bivalves have been published before now [23,24,25].Given the lack of data for aquatic organisms, studies with mammals are provided.The trivalent La3+interfere with the immune defense and the function of the liver, spleen, heart and blood vessels and brain [26].Previous studies indicated that lanthanum chloride accumulated in brain [10] alter the learning capacity and memory in animals AbstractThe toxicological understanding of rare earth elements (REEs) in the aquatic environment is very limited and concerns are rising about their safety to the environment.This study aimed to determine the bioavailability of Lanthanum (La) in zebra mussel, to evaluate its effects after 14 and 28 days through a multi biomarker approach and to estimate the cumulative effects of exposure to this lanthanide and air-time survival.Results showed that La was bioaccumulated in mussels but did not trigger metallothionein induction.In addition, La caused an antioxidant and prooxidant effects depending on the concentration and the duration of exposure but no genotoxicity was found.A significant decrease in glutathione-S-transferase activity was observed after 14 days but not after 28 days of exposure.Results revealed that low concentration of La enhanced citrate synthase activity, while high concentration trend to decrease its activity.Furthermore, this lanthanide did not significantly affect the airtime survival and mussel weight by comparison to control mussels.We suggested that La could contribute in the resistance of mussels to stress induced by air exposure by improving TCA cycle.This study demonstrates that La has diverse effect on mussel but further experiments are needed to elucidate its exact mechanism of action.