Distributions of Soil Contaminants and the Effect on the Efficacy of Salix Sp for Phytoremediation.

1.0 Introduction and Literature Review

1.1 Soil Contaminants

Human activities have caused the introduction of potentially damaging materials into the environment. These materials are pollutants and can now be found in the atmosphere, water, and land resources. Many of these contaminants are analogous to naturally occurring chemicals but the concentrations exceed the limits the environment can tolerate. Zinc is a naturally occurring component of all soils and is a vital trace element for all life when present in small quantities; around 40mg/kg is usual in soil (White and Zasoski, 1999). Where the metal is extracted and processed from its ore into elemental metal, the waste material contains zinc in concentrations exceeding the natural by many times. In this situation, a mineral essential to life becomes a toxic pollutant. Lead contamination is purely a by product of human activities and poses threat to ecosystem and human health alike (Dayton et al., 2006). Much effort has been placed into understanding the threat posed by these contaminants, and to design methods for alleviating the threat. Phytoextraction (the use of plants to take metals out of the soil) is a promising method for reducing soil pollution levels. This project will investigate the use of a woody plant species in practice for soil remediation, with a further dynamic in assessing the importance of contaminant distributions within the soil environment.

1.2 Historical soil contamination

With industrialisation and the industrial revolution, humans began to generate waste materials which required disposal. The surrounding environment often bore the brunt of the disposal effort. As time progressed and these wastes built up, it became apparent that the waste materials were having a negative impact on both human health and the health of the environment.

Unfortunately many pollutants persist in the environment over a long period of time. The threat posed by pollutants to both environmental...