Bioassessment of marine sediment quality using meiofaunal assemblages in a semi-enclosed bay

In order to assess marine sediment quality of a semi-enclosed bay, sediment and meiofaunal samples were analyzed at 35 stations in coastal waters of Bohai Bay, China. Concentrations of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn, Co and Mn) in sediment were measured and the Hakanson potential ecological risk index coupled with the ratio of nematodes to copepods (N/C ratio) was used. Results showed that the concentration of Mn was the highest while Cd was the main risk contributor. The Hakanson potential ecological risk index indicated that all pollutants posed low risks in the study area. However, the N/C ratio exhibited different results compared with Hakanson potential ecological risk index. BIOENV analysis identified the concentration of Ni and sediment grain size as the most important environmental variables influencing meiofaunal assemblages. The present study indicated that, in marine sediment quality assessments, meiofaunal assemblages should be involved besides pollutant concentrations.