Dr. Norman T., a professor of biology at the University of California, USA, used genetic engineering to increase the ability of plants to absorb selenium in the soil by more than five times. Soil contamination caused by toxic metals, selenium, is a problem faced by American farmers. Now Decontamination of soil has been done with chemicals that eliminate radioactive contamination or remove soil from the upper layers of the soil and transport it to a dedicated place for burial. However, this method is very expensive. Dr. Terry believes that transgenic plants can solve this problem and it is far cheaper than the above methods. Dr. Terry selected the Arabidopsis (Cruciferae) as his subject and the mustard had the natural ability to absorb selenium in the soil. The genetically modified Brassica genus cultivated by Dr. Terry can absorb 5.3 times more selenium in the soil without killing itself. The transgenic mustard can convert selenium into a compound. It is worth mentioning that Dr. Terry transplanted genetically modified mustards into drainage channels. Drainage channels drained sewage from farms, where a large amount of heavy metals accumulate. There is no one other than the genetically modified mustards that Dr. Terry cultivated. Plants can grow there. Dr. Terry pointed out that transgenic Arabidopsis can make selenium into dangerous volatile compounds that will be released into the air through the leaves. At the same time, U.S. Applied Plant Systems is working on a similar plan to develop a plant that can absorb mercury from the soil. However, before promoting the application of these new methods for decontaminating soils, it is necessary to find out what happens if insects eat these transgenic plants and the insects are eaten by birds. In short, the safety of the new method of recultivating the land is still a problem.