Linee Goswami

Metal contamination from coal ashes (CAs) is widely recognized as a significant environmental concern. To learn more about metal detoxification and accumulation potential of earthworm species, metal-rich tea factory coal ashes (TFCA) were fed to Eisenia fetida and Lampito mauritii by employing a fluorescent tag detection method. Fascinatingly, on feeding fluorescence probed Zn and Cd along with cow dung to Eisenia fetida, the detection of the gut-proteins with a molecular mass higher than 100 kDa was a distinct evidence of metal binding. Significant increases were observed in the content of humified organic C [humic acid (HAC) and fulvic acid C (FAC)] and degree of humification during vermicomposting. Concurrently, considerably large amount of toxic metals (Cr, Cd, Pb, and Zn) was transformed from exchangeable to recalcitrant (organic matter and mineral bound) fractions. Moreover, total metal concentrations were reduced with high removal efficiency upon vermicomposting.

India has a giant jute-producing basket which produces considerable quantity of toxic jute mill waste (JMW). Conversely, report on usability potential of JMW is rather scanty. The present study illustrates the efficiency of vermicomposting in bioconversion of JMW for agricultural use. Various combinations of JMW, cow dung, and vegetable waste were fed to Metaphire posthuma in vermireactors. Rapid increment of earthworm count, body weight, and cocoon production was evidenced. Total organic carbon and pH reduction was noteworthy, but N, P, and K availability, formation of stable humic acid C, fulvic acid C, and microbial biomass C substantially increased due to vermicomposting. FTIR spectroscopy confirmed a higher stability of vermicomposted JMW over the composted product. A significant decline in heavy metal concentration (Cr, Pb, Fe, and Zn) in the vermicomposted JMW further establishes the potential of vermicomposting with M. posthuma in successful conversion of the toxic JMW into valuable product.