**1. Introduction**

Excess amounts of pesticide have often been used to enhance the yield of agricultural products, and simultanously causing serious problems by polluting the soil and groundwater all over the world. For example, in the United States, large amounts of atrazine were used as a weed killer. The excessive atrazine sprayed by planes polluted rivers and soil near the farms, and this eventually was transferred to urban areas. The soil pollution in China is even more serious. Many agricultural fields and groundwater supplies are no longer used because of their contamination with pesticides and chemical fertilizers. An investigation by the FAO/ UNEP/WHO suggested that 1-5 million patients develop pesticide poisoning every year, and several thousand patients die [1].

As a result, many countries have passed laws about the remediation and conservation of soil. In the United States, the remediation and monitoring of polluted soil must be done based on the federal Superfund Act. In Germany, a law about the preservation of water and soil was passed in 1997. The remediation of soil is carried out according to these laws in these countries.

Among the various processes used for the remediation of soil, bioremediation has been remarkable because it is high safety and inexpensive running cost compared to the physical and chemical methods, such as burning and adsorption. Bioremediation methods can be classified into two broad classes (*in situ* and *ex situ* bioremediation), and *in situ* bioremediation processes employs the treatment method without moving the polluted soil. Some pilot studies have applied *in situ* bioremediation methods, such as bioventing and oxygen release com‐ pounds (ORC) methods, to remediate soil polluted by pesticides [2]. Such projects have succeeded in decreasing the herbicide concentration to a safe level, but large scale equipment and high expenses were major drawback associated with these methods. As most of the agriculture-related soil pollution occurs over a large area, bioremediation processes with high

© 2013 Shiomi; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

costs cannot be applied for this pollution. Therefore, the development of a new bioremediation method, which is applicable to huge areas and is low cost, has been desired.

females. The four female frogs could be fertilized by a male frog. These results strongly suggested that atrazine was harmful. The EU decided to prohibit the use of atrazine after noting that concentrations often exceeded the upper limit in groundwater. The US Environmental Protection Agency (EPA) set the upper limit of atrazine as 3 ppm in the drinking water, which was much higher than that in the EU. The EPA does not currently prohibit the utilization of atrazine, because the proof of adverse effects was not considered to be reliable. Therefore, atrazine is still used in the United States. Some specialists also warn that the sharp decrease of

A Novel Bioremediation Method for Shallow Layers of Soil Polluted by Pesticides

http://dx.doi.org/10.5772/56153

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In the 1980s, Roundup was developed by Monsant Company. Glyphosate-isopropyl ammo‐ nium is a main component of the herbicide. It inhibits the synthesis of an amino acid, and works against all kinds of plants. The company also developed genetically modified organisms (GMO) which were resistant to Roundup. Based on these successes, Roundup is widely used to grow GMO in the United States. However, excess utilization of the non-selective herbicides (2, 4-D and Roundup) causes a decrease in soil insects and bacteria, which supply the nitrogen,

As described above, the use of many harmful herbicides has been prohibited or regulated since the 2000s, and the pesticides showing low toxicity and a short retention time are now being used. However, dangerous pesticides continue to be used in many countries, especially

frogs in all over the world might be related to the excess use of triazine herbicides.

**Figure 1.** Pesticides commonly used for agriculture.

carbon and phosphate sources to plants.

In this chapter, the author proposed a novel bioremediation method called "Bioremediation with the self-immobilized system (BSIS)". Using this method, degrading microorganism can be self-immobilized by the help of *Bacillus subtilis*, and the immobilized cells rapidly degrade the pollutant in the shallow layer of the soil. The equipment and running cost associated with BSIS are low, and therefore, I think that this method is a superior method for remediating soil polluted by pesticides.
