Radiological Risk Assessment of Using DAP Fertilizer in Iraq

Agricultural and industrial fertilizers (phosphate or chemical fertilizers) have appeared as a prominent feature of agriculture. Modern methods to increase agricultural production and compensate for the lack of nutrients in the soil that is used for agriculture throughout the year or in successive years. To achieve the desired benefit from these fertilizers, they are added according to a well-studied program, in terms of quantity, quality and timing of adding these fertilizers, in proportion to the plant's growth stage and its needs. But the excessive and indiscriminate use of these chemical fertilizers, or the use of fertilizers with more radioactive activity than what is permitted to increase soil fertility, causes damage and sometimes catastrophic results to the soil itself, and to the biosphere and the environment. This confirms the necessity of evaluating the environmental impact of the use of these fertilizers in order to determine and avoid those Damages. This work presents the results of the determination of radioactive isotopes concentration in the most commonly used phosphate fertilizers employed in Iraq agricultural land (DAB fertilizer). The technique employed was the gamma spectrometry. DAB fertilizer samples were collected from different government storage in Iraq before used in agriculture and other samples of soils and plants was taken after used DAB fertilizer samples were collected from different government warehouses in Iraq before being used in agriculture and other soil and plant samples were taken after DAB fertilizer was applied to the soil to enhance crop productivity. The concentration of uranium in DAB fertilizer samples before using it to fertilize the soil ranged from 864.22±50.5 to 2550.2±124.68 Bq/kg, while its concentration in fertilized soil ranged from 864.22±50.5 Bq/kg, ranging from (15.2±0.91-21.74±1.14) Bq/kg. In the crops of these Soil ranges from (5.75±1.25 - 22.29±4.33) Bq/kg. The radiation dose to soil fertilized with fertilizer at a concentration of 864.22±50.5 was calculated and ranged from (0.0439 to 1.28) mSv/year. Samples (DAP3, DAP4, and DAP5) have dose values higher than the permissible safety limits, which are 1 mSv/year. When the value is greater than that, fertilizers are excluded and not used in agriculture. As for samples (DAP1, DAP2), the dose value was within the limits. Permitted and the results of this study agree well with results reported in the literature on similar fertilizers used in other countries.