**Abstract**

Bioaccumulation can be used as a measurement tool for analyses of sediment and soil toxicity. Heavy metal toxicity in sediments can be measured with bioaccumulation tests. Metal bioaccumulation has recently achieved more concentration from researchers due to its feasibility to conduct both field and laboratory experiments with indicative organisms. Bioaccumulation can be measured directly or using models. For this study, the concentrations of trace metals (Zn, Pb and Cu) in earthworm tissues were analyzed and compared with the total contents of heavy metals in contaminated parts of soils of Pallikaranai marshland. Samples were taken from different parts of the marshland, which have been reported to have heavy metal presence decades ago. Mostly predominant species found in the marshland *L. mauritii* and *P. excavatus* were used for the experiment. Soil samples were collected at six points along a gradient of increasing pollution. A regression model was applied to the results, and the order of accumulation of heavy metals BAF in the present study is Zn > Cu > Pb, indicating that zinc is a potentially high accumulating metal compared to Cu and Pb.

**Keywords:** bioaccumulation, bioavailability, heavy metals, benthic biota, sediment
