Treating Lead-Contaminated Soil by Stabilization and Solidification

Abstract

Soil in and near transportation facilities often is contaminated with lead because lead once was used as a base for gasoline and paint. Dealing with contaminated soil is difficult because the toxic material must be treated to protect the public from direct exposure. Stabilization and solidification is a promising technique for protecting the public from toxic materials in soils by decreasing the possibility of human exposure and decreasing the mobility of the contaminant. The results of a laboratory investigation of the feasibility of stabilization and solidification of contaminated soil using cement in combination with various additives are presented. Mobility of lead and other contaminants was measured by dynamic diffusion and compared with the standard test results of the toxic characteristic leaching procedure. Several additives were tried. Apatite and sodium silicate were found to be the most effective in reducing the mobility of the lead. The compacted dry density of the solidified soil had a great effect on the leaching characteristics. The leaching of lead from deteriorated solidified soil was simulated by crushing a sample containing apatite and conducting a dynamic diffusion test on the crushed sample. The diffusion coefficient was used to compare the effect of additives and other treatments.

Arsenic and lead release from fly ash stabilized/solidified soils under modified semi-dynamic leaching conditions

“…Arsenite (As 3+ ) is known to be more toxic and 25-60 times more mobile than arsenate (As 5+ ) [2,3]. Ingesting or inhaling Pb can damage the human nervous system, kidneys, blood vessels, brain, red blood cells, and digestive system [4], and human exposure to As and Pb has intensified as a result of industrialization. Arsenic is used in agricultural pesticides, the glass industry, and the copper refining industry.…”

“…Moreover, it is used in the production of semiconductors, pigments, and in the hardening of alloys [5]. Pb has been used in gasoline, paint, batteries, and cables [4,6]. As a result of the widespread use of both As and Pb over a long period of time, these elements have caused several human health prob- * Corresponding author.…”

Immobilization of lead in contaminated firing range soil using biochar

“…In 2006, more than 70,000 tons of Pb was used in the USA for ammunition production including shots and bullets (USGS 2007). Pb can cause a variety of adverse effects that harm the brain, red blood cells, blood vessels, kidneys and the nervous system (Lin et al 1996;Long and Zhang 1998). Typical 4 military-grade bullets are mainly composed of Pb alloy slugs enclosed within Cu alloy jackets (Dermatas et al 2004).…”

Effects of pH on leaching behavior of compacted cement solidified/stabilized lead contaminated soil

“… and Moon and Dermatas investigated the leaching behaviors of various metals from quick lime/fly ash stabilized soils by conducting semidynamic leaching tests with 0.014 N acetic acid (pH 3.25). Long and Zhang evaluated the effectiveness of different proportion of quicklime, fly ash, clay, phosphate and silicate in conjunction with cement to treat lead contaminated soils. Du et al .…”

“…Moon et al [25] and Moon and Dermatas [26] investigated the leaching behaviors of various metals from quick lime/fly ash stabilized soils by conducting semidynamic leaching tests with 0.014 N acetic acid (pH 3.25). Long and Zhang [15] evaluated the effectiveness of different proportion of quicklime, fly ash, clay, phosphate and silicate in conjunction with cement to treat lead contaminated soils. Du et al [27] evaluated the leaching characteristics of cement stabilized lead-contaminated soil in different leachate with the pH value of 2.0, 4.5, and 7.0, but leaching mechanism of lead was not investigated.…”