Sediment Contact Assay Using the Carpet Shell Clam, Ruditapes decussatus L., Embryos and Larvae for Assessing Contamination Levels of Four Sites in Tunisian Coast

This study assessed sediment pollution along the Tunisian coast using the sediment contact assay with embryo and larval life-stages of the clam Ruditapes decussatus. Sediment was collected from four sites for testing: Mahres, Monastir lagoon, Zarat and Chebba. Embryo development was significantly (p < 0.05) inhibited in sediment at concentrations a parts per thousand yen5 g L-1 from the Mahres and Monastir sites, and a parts per thousand yen25 g L-1 with sediment from the Zarat site. Sediment from the Chebba site had no effect at concentrations up to 125 g L-1. Compared to the control, the percentages of larval mortality were significantly higher in sediment from Monastir, Mahres and Zarat at sediment concentrations a parts per thousand yen25 g L-1; mortality increased with increasing sediment concentration to 50.1 %, 39.5 % and 31.2 % respectively at 125 g L-1. Chebba sediment did not affect the survival of larvae.