Shawnee A



M. Lambert(1), G.M. Pierzynski(2), and G. Hettiarachchi(2), (1)Geology, (2)Agronomy Kansas State University, Manhattan, Kansas 66506 The site of an abandoned lead smelter near the village of Dearing in southeastern Kansas is a continuing environmental and health concern because of the high levels of lead and cadmium contamination at the site. In the present study, samples of the slag were incubated in the laboratory, with treatments of two different forms of soluble phosphate (apatite and potassium phosphate, KH2PO4).

Phosphate amendment of lead-contaminated soils is known to precipitate highly insoluble lead pyromorphite (Pb5(PO4)3Cl), effectively reducing its bioavailability to humans, animals, and plants. The situation with phosphate-amended, cadmium-contaminated soils and slags is less clear. In the present study, lead content of the amended slag decreased in the exchangable, carbonate, iron- and manganese-oxide, and organic fractions of the slag, and increased in the residual or recalcitrant fraction.

Cadmium content of the phosphate-amended slag decreased in the exchangable fraction of the slag, and increased in the carbonate and iron- and manganese-oxide fraction. At the same time, X-ray diffractometry shows that pyromorphite abundance increased in the phosphate-amended treatments. Lead in the phosphate-amended slag precipitated as highly insoluble pyromorphite, and cadmium may have precipitated as relatively insoluble octavite (CdCO3).

Of the two phosphate amendments, KH2PO4 was more effective in reducing soluble lead and cadmium, and increasing pyromorphite abundance. The effect of rate is more effective in remediating the slag than the effect of time.

Key words: lead pyromorphite, bioavailability, phosphate amendment

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Tuesday, May 20, 1997

Metals Kansa A

Remediation of Munitions Compounds Kansa B

Analytical Methods Kansa C/D

General Topics Kansa B

Wednesday, May 21, 1997

Metals Kansa A

Zero-Valent Metals Kansa A

Remediation Kansa A

Vegetation-based Remediation Kansa B

Partnerships & Innovative Technologies Kansa C/D

Nonaqueous Phase Liquids Kansa C/D

Thursday, May 22, 1997

Biofilms & Barriers Kansa A

Bioremediation Kansa B

Partnerships & Technology Innovations Kansa C/D

Remediation Kansa C/D


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