Bioconcentrations of metals (Fe, Cu, Zn, Pb) in earthworms (Eisenia fetida), inoculated in municipal sewage sludge: Do earthworms pose a possible risk of terrestrial food chain contamination?

Abstract

Efforts have been made to evaluate the possible risks of metal bioaccumulation in composting earthworms during vermicomposting of hazardous wastes, e.g., sewage sludge. The sewage sludge was diluted by mixing cow dung in different proportions, and vermicomposted sludge as well as inoculated earthworms were analyzed for metal (Fe, Cu, Zn, Pb) contents. The sludge processed by worms showed a significant reduction in concentration of metals, Cu (29.4-51.6%), Fe (13.1-19.9%), Zn (15.2-25.8%), and Pb (4.6-46.9%), at the end. A considerable concentration of metals, total Cu (16.7-27.6 mg kg 21 ), total Fe (42.9-89.8 mg kg 21 ), total Zn (5.85-75.0 mg kg 21 ), and total Pb (1.79-12.4 mg kg 21 ), in composting earthworms was also recorded. The greater values of bioconcentration factors for metals suggested the possible risk of entering contaminants in higher food chains; since, earthworms are near to the terrestrial food chain, they can potentially mediate metal transfer from soil to a range of predators, including birds. Therefore, feasibility of vermitechnology in hazardous waste recycling needs close attention in respect to possible risk of environmental contamination. # 2008 Wiley Periodicals, Inc. Environ Toxicol 24: 25-32, 2009.

Effect of Concentration of Silver Nanoparticles on the Uptake of Silver from Silver Nanoparticles in Soil

“…Past studies have found insects to uptake bulk metals from soil [42][43][44]. In the present study, an uptake of silver from Ag NPs as a function of concentration of Ag NPs in soil was observed.…”

Indication of metal homeostasis disturbance in earthworm Eisenia fetida after exposure to semi-solid depot sludge

“…Many studies have reported that concentrations of metals (such as Cd, Cu, Fe, Pb, and Zn) in whole worms are directly related to availability of metals in soil (Morgan and Morgan, 1998;Suthar and Singh, 2009;Nannoni et al, 2014). The uptake of Cd and Pb in earthworms was even sometimes characterized by linear pattern, due to their commonly very slow or non-existent elimination (Giska et al, 2014).…”

“…The specific aims of the study were: (1) to define the level of metal/metalloid contamination of depot sludge; (2) to establish a baseline for metal/metalloid elements in whole earthworm tissues, as well as for the first time in the soluble tissue fraction, based on the measured concentrations in non-exposed organisms; and (3) to study the patterns of metal/metalloid variability in earthworms after exposure to depot sludge. Commonly, only few selected elements are monitored in the earthworms, such as Cd, Cu, Fe, Pb, and Zn (Carpené et al, 2006;Kamitani and Kaneko, 2007;Suthar and Singh, 2009;Li et al, 2010;Giska et al, 2014). Only seldom studies extend on larger number of elements (Nahmani et al, 2007b;Nahmani et al, 2009;Nannoni et al, 2014).…”

Worldwide earthworm research: a scientometric analysis, 2000–2015

“…Earthworms are of major importance in soil processes (Carnovale et al 2015). They perform essential role for soil health, microbial structure, nutrients and carbon cycling (Toyota and Kimura 2000;Fahey et al 2013), indicating active role in agricultural restoration, environmental indicators and bioconcentration and bioavailability for contamination (Pass et al 2015;Suthar and Singh 2009). However, exotic earthworm invasion resulted in significant negative impact on soil profiles, understory plants, fungus and nutrient cycling in non-native earthworm area (Holdsworth et al 2007;Suarez et al 2004;Belote and Jones 2009).…”