Effect of crab activities on distribution of heavy metals in estuarine intertidal sediments

Based on the field quadrat investigation of crab holes in intertidal sediments, together with the experiment of crab activities in a box, the effects of crab activities, such as digging tunnels and eating, on the distribution of Cu, Pb, Fe, Mn, Zn and Cr in intertidal sediments were studied. The results showed that the surface areas of intertidal sediments for exchanging could be obviously increased by crab activities. The content of organic matters in the sediments and the characteristics of particle size around the tunnels made by crabs could also be changed, resulting in an increase of heavy metals in sediments and providing more heavy metal sources for the exchanging process at the sediment-water interface. The effect of crab activities on the vertical distribution of heavy metals in sediments was closely related to the texture of sediments.