Estimating the Effect of pH, Moisture and Heavy Metal’s Interaction on Worm’s Bioaccumulation Using a Linear Model

In the process of vermicomposting, the earthworms Eisenia fetida have been exposed to various metals with different concentrations to investigate the effects on worms’ bioaccumulation. The study was carried out within 14 days of exposure. Five different chemical compounds in various concentration levels were added as mixture solutions to the experimental containers. Metals concentrations were measured in earthworms by atomic absorption. Ordinary least square technique was used to show metal bioaccumulation in the samples. The model showed interaction of the metals is significant. Moisture in soil had a negative effect on the rate of bioaccumulation. In contrast, pH demonstrated a large positive effect. In the experiments, worm bioaccumulation was significant for Zinc, Nickel, the most toxic metals such as Cadmium, and Chromium. Results led to a linear association between the bioaccumulation and the amount of heavy metals given the interaction as well as the rate of body burden of the worms which in turn, was affected by pH and moisture content.