This invention relates to a method for removing agricultural chemicals, such as pesticides, insecticides, herbicides, etc. which have been applied to seed grain kernels.
In the major grain-growing countries, seed grains are raised to provide the basis for the next year's grain crop. In order to prevent or retard degradation of the seed crop after it is harvested and awaiting use or when planted in the next season, certain agricultural chemicals are applied to the seed grain kernels. Additionally, because crop pests can be imported into a country not affected by the particular pest, pesticides can be applied to the seed grain kernels in order to insure that import of the seed grain does not also result in the import of unwanted pests. Finally, unused treated seed grains may have utility for either human or livestock consumption, if the agricultural chemicals are first removed to a level such that no danger exists from contamination by the chemicals.
For example, insecticides and pesticides are applied to the seed grain kernels in a slurry in order to assure uniform application. Usually, the pesticide is applied with an indicator dye (typically red or pink) to assure that any person handling, consuming, or feeding the treated grain is aware that it is treated with potentially hazardous materials. The seed kernels are passed through a device which applies the chemicals in an aqueous slurry which applies the appropriate amount of the various chemicals. Exemplary of the chemicals applied to, for instance, seed corn, are captan (3a, 4, 7, 7a-Tetrahydro-2-[tri-chloromeththio]-4-cyclohexene-1.2-dicarboximide), also known as SR-406, orthocide-406, Vancide 89, and methoxychlor (1.1'-[2.2.2-Trichloroethylidene]-bis [4-methoxybenzene]), known as DMDT, methoxy-DDT, and malate. Captan is applied at about 800 ppm, while methoxychlor is applied at about 70-80 ppm. A conventional indicator dye is Rhodamine B.
Presently, treated seed grains are often exported to countries with less rigorous environmental and human toxicity standards; however, such practices raise ethical as well as legal issues. Such products are now treated in some states as a hazardous waste, causing great expense for their disposal by conventional means, such as landfills. A commercially practicable process which would render treated seed grains usable for feed or consumption would convert such products into an asset rather than a liability. Such process would be politically as well as environmentally advantageous, given the current desire to minimize waste production and develop technologies permitting waste materials to be upgraded and/or recycled.
Therefore, it is an object of the present invention to provide a process whereby seed grains treated with agricultural chemicals, such as insecticides, fungicides, and herbicides, are rendered usable for human or livestock consumption.