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Pollution of the environment with toxic metals is widespread and often involves large volumes of wastewater. Remediation strategies must be designed to support high throughput while keeping costs to a minimum. Biosorption is presented as an alternative to traditional physicochemical means for removing toxic metals from wastewater. We have investigated the metal binding qualities of two biomass byproducts that are commercially available in quantity and at low cost, namely "spillage", a dried yeast and plant mixture from the production of ethanol from corn, and ground corn cobs used in animal feeds. The biomass materials effectively removed toxic metals, such as Cu, Cs, Mo, Ni, Pb, and Zn, even in the presence of competing metals likely to be found in sulfide mine tailing ponds. The effectiveness of these biosorbents was demonstrated using samples from the Berkeley Pit in Montana. Investigations included column chromatography and slurry systems, and linear distribution coefficients are presented. X-ray spectroscopy was used to identify the binding sites for metals adsorbed to the spillage material. The results of our experiments demonstrate that the biosorption of metals from wastewaters using biomass byproducts is a viable and cost-effective technology that should be included in process evaluations.

The earthworm Eisenia fetida is frequently used in ecotoxicological studies; however, it has not yet been investigated using proton nuclear magnetic resonance ((1)H NMR) metabolic profiling methods. The present study investigates the impact of depuration time, sample homogenization, and different extraction solvents on the quality and reproducibility of the (1)H NMR spectra of E. fetida with the goal of determining whether this species is suitable for future metabonomic studies. A depuration time of 96 h, followed by intact lyophilization before homogenization and extraction into a deuterium oxide (D(2)O)-based phosphate buffer, was found to produce extracts with excellent (1)H NMR reproducibility. The D(2)O buffer extracted the largest quantity of the widest variety of earthworm metabolites, which is consistent with the results from other studies using different earthworm species. Nuclear magnetic resonance assignments of the major metabolites in the D(2)O-based buffer also were performed and found to be similar to those for other earthworm species, such as Eisenia veneta, but also to have characteristic attributes in E. fetida. The major metabolites identified include amino acids (alanine, arginine, glutamic acid, glutamine, glycine, leucine, lysine, phenylalanine, serine, tyrosine, and valine), two sugars (glucose and maltose), the sugar alcohol mannitol, and the polyalcohol inositol. Two other earthworm species (Lumbricus rubellus and Lumbricus terrestris) also were examined using protocols developed for E. fetida, and of the three species, the (1)H NMR spectra of E. fetida had the least variation, indicating this species is well-suited for future metabolomic-based ecotoxicity studies.

Environmental context. Polycyclic aromatic hydrocarbons (PAHs) are common contaminants, but there has been limited research investigating the responses of earthworm exposure to sub-lethal PAH concentrations. In this study, 1H nuclear magnetic resonance (NMR) metabolomics was used to characterise the metabolic responses of Eisenia fetida earthworm exposure in contact tests to 10, 50 and 100 μg cm–2 naphthalene, phenanthrene and pyrene. The findings of this study highlight the potential of metabolomics as a tool for monitoring earthworm responses to sub-lethal concentrations of problematic environmental contaminants. Abstract. Metabolic responses of earthworm exposure to the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene and pyrene in contact tests were measured using 1H nuclear magnetic resonance (NMR). Novel metabolites were not detected but principal component analysis (PCA) showed that earthworms exposed to 10, 50 and 100 μg cm–2 naphthalene, phenanthrene and pyrene differed from unexposed (control) earthworms. Partial least-squares-discriminant analysis (PLS-DA) showed that earthworms had statistically significant responses to PAH exposure, except for 10 μg cm–2 naphthalene and 50 μg cm–2 pyrene. Leucine, valine, alanine, lysine and maltose were identified as potential response indicators of PAH exposure, but whether the concentration of these metabolites increased or decreased was PAH- and concentration-dependent. These initial findings reveal the potential of metabolomics for monitoring earthworm responses to sub-lethal PAH exposure and highlight the role of metabolomics as a future tool in ecotoxicology.

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