Highways are known to be a source of several toxic pollutants including the heavy metals lead, zinc and chromium. The need to manage highway runoff in a manner which reduces or eliminates the loading of heavy metals to receiving waters is evident, but more research has been required to develop cost-effective ways of meeting this need. Recent studies have indicated that the soil is a significant "sink" for heavy metals, allowing speculation that management practices which make use of the soil to retain metals from highway runoff should be employed. The purpose of this study is to evaluate the ability of the soil to retain heavy metals and to document some of the soil properties and reactions which are responsible for this ability. This was accomplished through a combined effort of literature review and laboratory analysis of in situ soils from the right-of-way area of 5 Central Florida highways. A total of 13 samples were analyzed, for pH, cation exchange capacity, organic matter content, grain size, and concentrations of lead, zinc and chromium. The samples were separated into 6 fractions according to density and each fraction was analyzed for lead, zinc, and chromium. The step allowed reasonable estimates of the relative importance of soil components (clay minerals, organic matter) and/or soil-heavy metal interactions (precipitation, complex formation, etc.). It was found that the soils tested can likely retain between 10 and 500 times their existing lead content. Evidence for the formation of a dense lead compound (or precipitate) in edge of pavement surface soils was found. Organic matter was identified as an important soil component for retention of lead, zinc, and chromium. However, metal retention was found to be dependent on many soil properties and chemical reactions.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:rtd-1271 |
| Date | 01 April 1978 |
| Creators | Bell, John H. |
| Publisher | Florida Technological University |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Retrospective Theses and Dissertations |
| Rights | Public Domain |
Page generated in 0.002 seconds