Evaluation of Site Contamination from Storage of Fertilizer

Abstract

Australia has extensive agricultural production of crops and livestock production. Regular fertilizer application maintains production rates of grain crops. Large quantities of phosphorus-based fertilizers are produced from phosphate rock by sulfuric acid extraction at designated production works at coastal locations and transported by train to distribution points in selected agricultural areas. Bulk fertilizer is stored in large sheds adjacent to railway lines and large or small trucks then make deliveries to farms. When such sites are disused or abandoned, contaminated soil may remain from fertilizer constituents. Occasionally fertilizer storage sites may have experience accidental contamination from railway engine or truck hydrocarbons. The objective of this study is to examine the extent of fertilizer contamination at agricultural storage sites, identify environmental risks associated with the handling practices of storage sites, and distinguish from other contamination from transport vehicles. Soil samples were collected at two locations using a grid-base sampling program to identify contaminants. Following preparation soils were analysed for phosphorus, sulfate, sulfur, petroleum hydrocarbons (aliphatic and aromatic), heavy metals and pesticides using standard procedures. A ’within a target area’ was used to assess contamination levels by comparing the 95% Upper Confidence Limit (UCL) of the average concentration of each analyte of concern against respective ’contamination’ criteria for industrial sites; exceedance of the 95% UCL against site criteria identified contamination. Statistical analysis of the data for different analytes in soil at fertilizer storage sites showed the relationship between contaminant levels and dispersion over respective sites and extent of contamination from fertilizer handling activity and other vehicle- related site contamination. In conclusion accurate estimation of contamination of sites can be provided using the grid-base sampling approach and 95% Upper Confidence Limit (UCL) criteria to distinguished transport vehicle-related contamination from phosphate-based fertilizer on site.