Accumulation of Heavy Metals from the Combination of Different Biological Wastes by Earthworm Lampito mauritii Kinberg

Abstract

Heavy metals are a serious problem that caused several health problems in humans and animals. They also affect the diversity of soil fauna as well as the environment. The proper management of heavy metal concentrations can be managed by the inoculation of earthworms in their habitats. Through bioaccumulation of heavy metals in their body, earthworms reduce the toxic level of heavy metal concentration. Lampito mauritii is common earthworm species that accumulate heavy metals in its body tissues. Heavy metal concentration was observed in different animal dung with municipal solid waste (MSW) and final vermicompost as well as in earthworm bodies. A significant decrease in heavy metals concentration such as cobalt (Co), chromium (Cr), lead (Pb), nickel (Ni), and cadmium (Cd) was observed in all the combinations of different animal dung with MSW after vermicomposting by earthworm Lampito mauritii. A significant reduction of cobalt (Co) was observed in the vermicomposts obtained from buffalo dung, whereas cow dung only has a significant maximum reduction in the level of chromium (Cr) (91.48%, 0.072 ± 0.002 mg/kg). The maximum reduction of lead (Pb) concentration was observed in the vermicomposts obtained from the combination of buffalo dung with municipal solid waste in the ratio (1:1) (96.61%, 0.060 ± 0.003 mg/kg). There was a significant decrease in the concentration of nickel (Ni) in vermicomposts of all combinations of animal dung with municipal solid wastes. Whereas, the concentration of cadmium (Cd) is significantly reduced in the vermicomposts obtained from goat dung (95.62%, 0.017 ± 0.005 mg/kg). The result of this study clearly illustrated that during vermic-activity, Lampito mauritii considerably decreases different heavy metals in the final vermicompost and can act as a biological indicator of soil quality. With the help of this technique, MSW can be managed effectively while also being protected from toxic levels of heavy metal contamination in the human diet.