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Dbg corn silo kansas8/10/2023 ![]() Measurements taken at Centralia before and after the injection of a commercial product containing the specially coated iron microparticles showed a drastic reduction in the amount of carbon tetrachloride present in the soil. “Feeding the bacteria creates the conditions necessary for the whole process to work.” “The only way to prevent the buildup of chloroform was to find a way to remove the oxygen and produce the optimum environment for the right reactions to occur,” Alvarado explained. This process, according to Alvarado, touches off a chain of other chemical reactions that result in the transformation of most of the carbon tetrachloride into another toxic compound, chloroform, which is an even greater hazard in drinking water. At first glance, the mechanisms appeared to be very simple, but more detailed observations revealed additional complex pathways and products that could result from transformation of carbon tet. In prior work, scientists using uncoated iron nanoparticles had been able to break some of the carbon tetrachloride bonds. ![]() To clean up the Centralia site, the Argonne group needed to find a way to break those bonds and chemically strip the individual chlorine atoms - which would then ideally become relatively harmless chloride ions - from the carbon at the center of the molecule. In its molecular form, carbon tetrachloride consists of a central carbon atom bonded to four chlorine atoms. ![]() “The only sources of groundwater in these areas of the country are shallow aquifers, which are much more prone to this kind of contamination,” Alvarado said. In certain areas of high agricultural use, carbon tet leached from the soil into the water table, where large quantities have remained for decades. ![]() “It’s a hard case because the bonding within the compound is so strong.”Įven though the federal government banned the use of carbon tetrachloride as a grain fumigant in 1985, a good deal of damage was already done. “Carbon tetrachloride was a real challenge to us because its chemical structure is extremely stable,” said team member and Argonne environmental scientist Jorge Alvarado. However, scientific studies showed that exposure to carbon tet resulted in liver, kidney, and central nervous system degeneration as well as increased rates of cancer. It worked as a powerful cleaning agent and as a refrigerant, and in the Midwest it was used as a pesticide to protect stored grain. The researchers coated the microparticles with organic material, which served as bait for bacteria that created the conditions necessary to safely convert the toxic chemical into non-hazardous substances.īack in the 1960s, carbon tetrachloride - or “carbon tet,” as it is more commonly known - was widely thought to be a miracle chemical. Last year, a team of Argonne scientists led by Lorraine LaFreniere injected iron microparticles underneath fields long-polluted with carbon tetrachloride near Centralia, Kansas. Department of Energy’s Argonne National Laboratory has demonstrated a way to enlist bacteria in the fight to cleanse some of the country’s most intractably polluted locations. had the highest pH values in 1990, whereas forage sorghum silages had the highest values in 1991.However, a new study conducted by environmental scientists at the U.S. had higher pH values than that in the second 18 in. The dry matter (DM) contents were lower in forage sorghum silages than in corn silages, and DM contents of sealed silages were lower than those of unsealed silages in both years. by 4 percentage units in 1990 and 13 units in 1991. Sealing reduced losses in the second 18 in. in 1991 than 1990 sealing reduced spoilage losses of OM at that depth by 16 and 37 percentage units in 19, respectively. All silages had greater estimated spoilage losses in the top 18 in. ![]() Sealing silos dramatically reduced the estimated spoilage losses in the top 3 ft. Losses of organic matter (OM) from spoilage were estimated by using ash content as an internal marker. Ninety-five percent of the silages were either corn or forage sorghum, and only 22 percent of the silos were sealed with polyethylene sheeting. of silage from each of 30 horizontal silos in western Kansas was sampled at three locations across the width of the silo for 2 consecutive years (19). ![]()
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