Leaching potential assessment of atrazine and nitrate in sugarcane field, Suphan Buri Province

Abstract

Atrazine is widely used as a herbicide to control annual broadleaf in agricultural area such as rice and sugarcane. It is considered as one of endocrine disrupting chemicals. Atrazine also affects liver, the central nervous system, immune system and cardiovascular function. The study area is sugarcane field in U-thong and Song Phi Nong district, Suphan Buri province. In this area, soil and groundwater samples were collected at eight different points distributed over the sugarcane area with different soil types. Batch adsorption experiment was carried out to evaluate the proper adsorption isotherm of each soil. Additionally, groundwater samples were analyzed for nitrate concentration. For the leaching potential assessment, AF/RF model was used because the model requires only basic parameters of the pesticide and soils. AF/RF model is tier-1 model using for defining pesticide leaching index for preliminary assessment in the area with the limited data availability. The result of batch sorption experiment indicated that soil samples were well fitted with Freundlich isotherm. Kf was found in the range of 0.284 to 0.822 L/Kg. Additionally, 1/n was reported in the ranged of 0.401 to 0.855. High nitrate concentration was also found in groundwater in the range of 3.25 to 71.11 mg/L. As a result from AF/RF model, most of the area was considered as high leaching potential for atrazine and nitrate in this study area. Moreover, there also were soil samples with low to moderate leaching potential due to the different soil types and sorption behaviors. The detected nitrate concentration conforms to the leaching potential of S1, S2, S4, S5 and S6. In the other words, the result of the leaching potential model showed 62.5% efficiency as a model performance.