Study on the Application of Aluminum Phosphide using the Conventional System Compared to the Long Probe in Soybean Meal Stored in Bulk

Brazil is one of the mayor's producers and an exporter of grains requires the purging of these pests from some importing countries seeking preventing these pests to be brought with the grains or meals. Phosphine is the most widely used fumigant worldwide; its application is done though a solid formulation, which once exposed to the environment humidity, will slowly release the phosphine gas through a hydrolysis reaction [1]. Usually the grains or meals receive the application on the surface at a dosage comprised of one or two grams of the active ingredient/m3 of volume of the environment. After applying, the compartment is hermetically sealed on order to prevent leakage of the fumigant. Vessels with 14-20 m deep compartments will never achieve the desired efficiency when using the conventional purging system if the phosphine is not evenly distributed onto the grains or starches. This study compare the conventional method with uniform distribution of phosphine; besides the inefficiency of the treatment due to misdistribution of the gas, this type of treatment in this environment builds a highly dangerous amount of gas. The test were performed in the region of Paranagúa - PR, using five cylindrical plastic tubes of 30 cm in diameter x12 m long, which were filled with soybean meal for appropriate treatments. Making holes on the tubes at every one meter, which were property sealed and constructed to allow the visualization of the gas displacement along the pipe during the period after the application. The treatments were as followings: 1- 1 g/m3 tablets of phosphine on the surface of the mass (conventional system); 2-1 g/m3 tablets on the bottom of the mass;3-g/m3 tablets on the bottom of the mass, and having motor for circulation of the gas; 4-1 g/m3 tablets evenly distributed in the mass, at every meter (long tube system) and 5-1 g/m3 filling up only ½ of the mass and placing the tablets on the surface (slack system). The results demonstrate that the current system of fumigation (tablets or sachet left on the surface of the mass of the grains or starches are not effective and can cause accidents. Compromising public bodies responsible for overseeing the efficient and safe fumigation.