Selenite and selenate determination in surface coal mine backfill ground water

Conference · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:100188

Reddy, K J; Zhang, Z; Vance, G F ^[1]

---

1. Univ. of Wyoming, Laramie, WY (United States)

A majority of Wyoming`s public water supplies are based on ground water resources. It is necessary, therefore, to protect these resources from contamination by pollutants (e.g., selenium), which can be harmful to human health. Dissolved selenium (Se) in ground water may contain different species, including selenite (SeO{sup 2-}{sub 3}), selenate (SeO{sup 2-}{sub 4}), organic Se, and Se ion pairs (e.g., MgSeO{sup {degrees}}{sub 4}, CaSeO{sup {degrees}}{sub 4}). For an understanding of the toxicity potential of Se, it is necessary to know the concentrations of SeO{sup 2-}{sub 3} and SeO{sup 2-}{sub 4}, as well as total Se content in ground water. The hydride generation atomic absorption spectrometry (HGAAS) method of Se analysis requires oxidation of organic matter, which destroys the natural distribution of Se. Ion chromatography (IC) can determine SeO{sup 2-}{sub 3} and SeO{sup 2-}{sub 4} concentrations, but other common anions (e.g., SO{sup 2-}{sub 4}) will interfere with SeO{sup 2-}{sub 3} and SeO{sup 2-}{sub 4} measurements. The objective of this study was to determine SeO{sup 2-}{sub 3} and SeO{sup 2-}{sub 4} concentrations to evaluate the chemical speciation of Se in ground water. Both SeO{sup 2-}{sub 3} and SeO{sup 2-}{sub 4} from ground water samples were adsorbed onto copper oxide (Cu) at pH 5.5 and subsequently desorbed with NaOH solution at pH 12.5. Extracted SeO{sup 2-}{sub 3} and SeO{sup 2-}{sub 4} were determined using HGAAS and IC. From the SeO{sup 2-}{sub 3} and SeO{sup 2-}{sub 4} measurements, Se speciation in ground water was calculated. Results showed that dissolved Se concentrations in ground water ranged from 22 to 151 {mu}g/L. These results also show that mobility of dissolved Se will depend on the chemical form in which Se is present in the ground water.

• OSTI ID: 100188
• Report Number(s): CONF-9506226--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
BACKFILLING
CHEMICAL ANALYSIS
COAL MINES
ENVIRONMENTAL TRANSPORT
GROUND WATER
HYDROLOGY
SELENIUM COMPOUNDS
SURFACE MINING
WATER POLLUTION