Heavy Metal Contamination in Agricultural Soils Global Issues

Heavy Metal Contamination in Agricultural Soils Global Issues Seminar Colorado Mountain College Maggie Gaddis, adjunct faculty

Outline • What is a heavy metal? – What causes heavy metal pollution? – International Examples- Zimbabwe, China • Remediation Techniques – Historic technique – Modern techniques (pros and cons) – Phytoremediation (natural v. chemically enhanced) • Case Study- Hayden Ranch

What is a heavy metal?

What causes heavy metal pollution?

What is soil pollution?

Metals have unique chemical properties

International Example- Zimbabwe

International Example- China

Remediation Techniques • Traditional/historical approach: land fills, leave it on site, let it wash away • Microbial remediation • Site excavation and soil replacement • Soil washing, vapour extraction • Phytoremediation

Phytoremediation Phyto- plant Remediation- The act or process of correcting a fault or deficiency

Hyperaccumulators

Case Study- Hayden Ranch

Citations • Catlett, K. M. et al. 2002. Soil chemical properties controlling zinc activity in 18 Colorado soils. Soil Science Society of America Journal 66: 1182 -1189. • Ellis, R. J. et al. 2003. Cultivation-dependent and –independent approaches for determining bacterial diversity in heavy-metal contaminated soil. Applied and Environmental Microbiology. 69(6): 3223 -3230. • Facchinelli, A. et al. 2001. Multivariate statistical and GIS-based approach to identify heavy metal sources in soil. Environmental Pollution 114: 313 -324. • Fleming, S. W. Assessment of potential health effects of ingestion of garden produce containing arsenic and cobalt grown in Cobalt, Ontario. Risk Assessment unit, Hazardous Contaminants Branch. • Lombi, E. et al. 2001. Phytoremediation of heavy-metal contaminated soils: natural hyperaccumulation versus chemical enhanced phytoextraction. Journal of Environmental Quality 30: 191 -1926. • Muchaweti, M. et al. Heavy metal content of vegetables irrigated with mixtures of wastewater and sewage sludge in Zimbabwe: implications for human health. Dept. of Biochemistry, Univ. of Zimbabwe. • Sandhi, M. A. Heavy metal in the environment and effect on plant physiology. Powerpoint presentation accessed with Slideshare on 4 -20 -10. • Wong, S. C. et al. 2002. Heavy metals in agricultural soils of the Pearl River Delta, South China. Environmental Pollution 119: 33 -44.

Questions?