Trace metal pollution and its influence on the community structure of soft bottom molluscs in intertidal areas of the Dar es Salaam coast, Tanzania

► Influence of trace metals pollution on molluscs community structure along the Dar es Salaam coast was investigated. ► Despite significant enrichment of As, Sb, Mo, Mn, and Zn, Dar es Salaam sediments are within the recommended standards. ► Trace metal pollution explained 68% of variation in species composition. ► Gastropods Acteon fortis, Assiminea ovata, and Littoraria aberrans, were significantly negatively affected by As and Sb. ► Bioaccumulation of Cu, Zn, As, Cd, and Mo occurred in the bivalve Mactra ovalina and the gastropod Polinices mammilla.