Thursday, November 14, 2019
Phytoremediation: Insuring Safe Selenium Levels Essay -- Exploratory E
Phytoremediation: Insuring Safe Selenium Levels Selenium is a naturally occurring element found in soil. It becomes a problem when irrigation practices cause it to leach out of the soils in the western states. The selenium is deposited in the rivers, then accumulates until it reaches toxic levels. The high levels of selenium seriously affects the environment and agriculture downstream. However, with the use of phytoremediation, the possibility of safe selenium levels has never been closer. Selenium is an essential trace element, number 34 on the periodic table, that is found naturally in the environment. It is distributed in most rocks, soils, water, and living organisms. There are places in the U.S., Australia, and China that do not have enough naturally occurring selenium. However, most areas of the world contain significant amounts of the element (Bentor). Selenium is a micronutrient necessary for human and animal health. Supplements have been promoted as an aid in preventing many serious health problems, including cancer. It is thought to be an antioxidant that helps prevent damage done to cell tissues by free radicals. Selenium acts inside the cell to capture and destroy peroxides produced by the oxidation process of free radicals before they can alter the cell membrane (Coomer). However, there is a very small margin between the amount of selenium needed for optimal health and the amount that results in selenium toxicity in people. High levels of selenium can cause dizziness, irritability, fatigue, bronchitis, garlic breath odor, brittle nails and hair, and reduced hemoglobin levels (Canadian). In livestock, excessive levels of selenium are one of the main agents of poisoning in the western United States. Two ca... ...tml. Lemly, A. Dennis and Harry M. Ohlendorf. "Regulatory Implications of Using Constructed Wetlands to Treat Selenium-Laden Wastewater." Ecotoxicity and Environmental Safety. 2002. "Phytoremediation." Environmental Health Perspective. Volume 103, No. 12. Dec. 1995. "Selenium: A Window on Wetlands." 1 April 2004. http://www.lbl.gov/ MicroWorld/Wetlands.html. "Tools for Environmental Cleanup: Engineered Plants for Phytoremediation." 9 Mar. 2004. http://www.cfr.washington.edu/outreach/Phyto2003. "What is Selenium?" Gunnison Basin Selenium Task Force. 10 Mar. 2004. http://www.seleniumtaskforce.org/selenium.html. White, Ken. "Phytoextraction." Brookhaven National Laboratory. Chicago, IL. Feb. 2000. Yang, Sarah. "Wetlands Clean Selenium from Agricultural Runoff." 10 Mar. 2004. http://www.berkeley.edu/news/berkeleyan/ 2003/01/22/selen.html.