PHYTOREMEDIATION USING Hydrastis Canadensis
PHYTOREMEDIATION USING Hydrastis Canadensis
1.1 BACKGROUND TO THE STUDY
Remediation refers to the removal or transforming of contaminants to non-harmful or less harmful substances. It includes methods that reduce the mobility and migration of the contaminants preventing their spreading to uncontaminated areas and the toxicity of the contaminants remains unaltered but the risk posed to the environment is reduced (U.S. Dissolved Oxygen Demand, 1994). For the treatment of contaminated soil physiochemical and biological treatment is used such as incineration, thermal desorption, coker, cement kiln, solvent extraction and landfilling.
Incineration is an effective treatment method but it is costly and after burning the soil loses or reduces its nutritional value and structure. Landfilling does not remove the contaminant but only relocates the problem (Lageman et al, 2005).
The world depends on oil and large amounts is used, transported, processed and stored all over the world. In 2003, the total world consumption of petroleum was 13.1 billion litres per day. The United States Energy Information Administration projects world consumption of oil to increase to 98.3 million barrels per day (18.8 x 106m3day-1)in 2015 and 118 million barrels per day (18.8 x 106m3day-1) in 2030 (Environmental Impact Assessment 2006).
The most notable oil spills at sea involves large tankers such as Exxon Valdez which spilled thousands of tons of oil (Paine et al, 1996; Albaiges et al, 2006). These oil spills can cause severe damage to sea and shoreline organisms (Whitfield, 2003). The most responsible factors for contaminations are service stations, garages, scrap yards, waste treatment plants, sawmills and wood impregnation plants.
The development of petroleum industry into new frontiers, the apparent inevitable spillages that occur during routine operations and record of acute accidents during transportation has called for more studies into oil pollution problems (Timmis et al, 1998) which has been recognised as the most significant contamination problem (Snape et al, 2001).
Oil is a complex mixture of hydrocarbons and other organic compounds including some organometallic constituents (Butler and Mason, 2007). It contains hundreds of thousands of aliphatic, branched and aromatic hydrocarbons (Prince, 1993; Wang et al, 1998) most of which are toxic to living organisms (ATSDR, 1995). This engine oil renders the environment unsightly and constitutes a potential threat to humans, animals and vegetation (ATSDR, 1997, Edewor et al, 2004). Fat soluble compounds may accumulate in the organs of animals and may be enriched in the food chain even up to humans (Mackay and Fraser, 2000). Prolonged exposure and high oil exposure may cause development of liver and kidney disease, possible damage to bone marrow and an increased risk of cancer (Proset et al, 1999; Lloyd and Cackette, 2001; Mishra et al, 2001).
Oil stains can decrease the insulation of bird’s feathers, causing the bird to freeze to death. Oil also diminishes the ability of the birds to fly, dive and swim which leads to starvation. Birds also swallow oil when cleaning their feathers which causes intoxication (Environmental Protection Agency, 1999). In the long term, toxic and carcinogenic compounds can cause intoxication, diseases, cell damage, developmental disorders and reproduction problems (ATSDR, 1995). In addition to toxic effects, oil products can affect plants and animals physically.
A thick layer of oil inhibits the metabolism of plants and suffocates them. Destruction of plants affects the whole food web and decreases the natural habitats of numerous species (HELCOM, 2003). Hydrocarbon compounds such as petroleum are essential for life. Since they do not naturally occur in forms most useful to humans, they can be hazardous. Fuel and lubricating oil spills have become a major environmental hazard to date.
The contamination of the environment with petroleum hydrocarbons provides serious source of carbon and energy. He further recognised that the microbial utilization of hydrocarbons was highly dependent on the chemical nature of the components in the petroleum mixture and environmental determinants (Atlas, 1981).
Microbial degradation of pollutants has intensified in recent years as mankind strives to find sustainable ways to clean up contaminated environments (Diaz, 2008). Biodegradation of hydrocarbons by natural populations of micro-organisms represents one of the primary mechanisms by which petroleum and other hydrocarbon pollutants are eliminated from the environment.
The effects of environmental parameters on microbial degradation of hydrocarbons dissimilation by micro-organisms and the effects of hydrocarbon contamination on microbial communities have been areas of intense interest and the subject of several reviews.
1.2 STATEMENT OF THE PROBLEM
Crude oil pollution causes basic effects on the environment which leads to effective crude oil contamination that affects underground water quality and ecosystem.
1.3 AIM/OBJECTIVE OF THE STUDY
The aim of the study is how to use plant to remove contaminant from the soil using Hydrastis Canadensis.
1.4 SIGNIFICANCE OF THE STUDY
To discover a new method to remediate polluted soil.
1.5 SCOPE OF THE STUDY
The study is limited to the use of Hydrastis Canadensis to clean up contaminated soil.