Selenium-enriched dietary supplements containing various selenium compounds are readily available to consumers. To ensure proper selenium intake and consumer confidence, these dietary supplements must be safe and have accurate label claims. Varying properties among selenium species requires information beyond total selenium concentration to fully evaluate health risk/benefits A LC-ICP-MS method was developed and multiple extraction methods were implemented for targeted analysis of common “seleno-amino acids” and related oxidation products, selenate, selenite, and other species relatable to the quality and/or accuracy of the labeled selenium ingredients. Ultimately, a heated water extraction was applied to recover selenium species from non-selenized yeast supplements in capsule, tablet, and liquid forms. For selenized yeast supplements, inorganic selenium was monitored as a means of assessing selenium yeast quality. A variety of commercially available selenium supplements were evaluated and discrepancies between labeled ingredients and detected species were noted.

Wetland treatment has successfully removed nickel, copper, cobalt, and zinc from neutral mine drainage in northeastern Minnesota. Pilot and full-scale overland flow wetlands have removed up to 90% of the incoming nickel and 50% to 90% of the other metals. Nickel is the major contaminant in the mine drainage, with average concentrations from 2 to 5 mg/L. The other metals were generally present at concentrations less than 0.1 mg/L. In short-term tests, using drainage that contained around 1 mg/L zinc and 0.4 mg/L of copper and cobalt, concentrations were reduced abont 90%. Input and output flow and water quality measurements were collected, and a mass balance was calculated. To determine the fate of the metals and the removal mechanisms, samples of vegetation and peat were collected to examine the distribution, form, and depth of metal removal. Although the overall metal concentrations in the predominant vegetation types (cattail, grass, and sedge) had increased by factors ranging from 3 for above ground vegetation to around 14 for cattail roots, the mass of metal removed by the vegetation was less than 1 % of the total mass removed. The remaining metals were associated• with the peat substrate. Core samples of the peat were collected and divided into 2 to 4 cm sections. Each section underwent a sequential extraction procedure and was analyzed for total concentration and metal forms. Nickel removal occurred to a depth of 20 cm, with about 60% of the nickel being organically bound.

Coarse-textured taconite tailing cover about 3,000 ha on Minnesota's Mesabi Iron Range. These tailing are deficient in nutrients, cation-exchange capacity, and moisture-retention capacity and are highly erodible. Previous reclamation efforts, in most cases, have been unable to meet the regulatory requirement for 90% vegetative cover after 3 yr. Small-scale test plots have demonstrated that municipal solid waste compost can be used to successfully reclaim tailing areas, which also provides a use for the compost. There has been a general reluctance to use municipal compost for reclamation activities, however, owing to concerns relating to the release of metals and organics. A field demonstration study was initiated to examine the feasibility of applying the compost on a larger scale and to examine its impacts on water quality and runoff from the reclaimed areas. Three 0.1-ha plots were located on the south-facing slope (15% slope) of a coarse tailing dike. Three treatments were studied: (1) a control with no treatment, (2) standard diammonium phosphate fertilizer application of 448 kg/ha, and (3) a compost treatment with 224 kg/ha fertilizer and 44.8 Mg/ha (dry weight) of municipal solid waste compost. All plots except the control were seeded with a grass-legume mixture and mulched with hay. Runoff collection plots were set up, and lysimeters were installed in each plot. Three months after planting, ground cover was 67%, 39%, and 0% for the compost, standard fertilizer, and control plots, respectively. Biomass, as kilograms per hectare, was 976, 225, and O for the compost, standard fertilizer, and control plots, respectively. Chloride, sulfate, calcium, magnesium, sodium, and nitrate were elevated in the soil water of the compost plot. Nitrate was the only chemical that exceeded water quality standards; however, these concentrations are not expected to significantly impact the local aquifer because the compost is only applied once and the concentrations of all parameters decreased with time.