Arsenic pollution is a real problem with over 560 superfund-contaminated sites in the US, second in number of sites only to lead. (2) This problem is so vast the EPA wrote a whole manual on how to effectively treat the problem. The way that arsenic pollution can happen is through major excavations, most commonly in mining materials like coal, various metals, and also from pressure treated wood. Chromated copper arsenate was the chemical used on pressure treated wood starting in the 40’s. Since the 70’s this was the main treatment for wood used in home building, decks, railings, and children’s play structures until a recent ban on its widespread use. There is an estimated 600,000 metric tons of arsenic contained in wood products that have been treated in residential and commercial settings in the US alone. (8) In mining pollution, the Arsenic sits in bedrock bound to constituent molecules but when bedrock is disturbed arsenic is agitated and broke free. (7) The inorganic form is broken free in its various valence states. These valence states react with other organic molecules forming different organoarsenic structures. These different inorganic forms Arsenate and Arsenite then can become mobile through different organisms or physical transportation means. (4) The most common way for it to infiltrate soil is through runoff. This creates a growing risk when it comes to water, soil, and crops in near lying areas. This then becomes the responsibility of farmers, pedestrians who drink the water, and government agencies that regulate acceptable levels to figure means to clean or avoid the contamination.
The traditional way to clean up arsenic is to remove the contaiminated medium whethrer it be water or soil, through pumping or excavation then once it is isolated it would either be filtered and disposed of or incernerated and colledted. This is invasive, time consuming, inefficient, and also requires skilled technicians. There is a report put out by the epa that chronicles all these procedures then it also mentions technology and engineering of living organisms and the ways they can be used In Situ to help clean superfund sites.
Recently the acceptable level of arsenic for puplic water was changed from 0.050 mg/L to 0.010 mg/L creating a more pressing need to develop alternative methods. The most current mmethod for water treatment on a large system is precipitation/coprecipitation. This method works well with Arsenic as well as other heavy metals but in not as cost effective. Ion exchange is also utilized in water treatment but only practicle for smaller treatments. In soil applications solidification and stabilization is the method used. This treatment immobilizes Arsenic and reduces the leachability of arsenic. Pyrometallurgical processing is another method but is more costly due to having transport the soil to the site of the incinerator.
The rationale for using genetic engineering...