Effects of fertilizer industry emissions on local soil contamination: a case study of a phosphate plant on the east Mediterranean coast.

Abstract

Fugitive dust emission, transport and deposition from phosphate fertilizer industries may pose an environmental hazard to the surrounding environment, particularly to soil. This study is to evaluate such hazard by investigating the fate of airborne pollutants, their transfer from atmosphere to soil surface, and their contamination potential. Concentrations of elements were measured in soil samples. Elemental analyses were carried out using ICP-AES and ICP-MS. Analysis of speciation of trace elements, using a sequential extraction method, was performed on the plant's raw material (apatite), product and waste (phosphate fertilizer and phosphogypsum). A model estimating local atmospheric dry deposition was formulated. Statistical analyses were performed on sample data. Measured phosphorus accumulated considerably to the north-east of the plant, mainly due to the prevailing wind and associated dry deposition. Results exhibited considerably above-threshold enrichments in potentially toxic, bio-available trace elements (Cd, Zn) (2.5-6.9, 295-506 mg kg(-1)) and radionuclide (U, 20-98.69 mg kg(-1)) within a major deposition area. Speciation results revealed Zn and Cd occurring predominantly in mobile phases within the pollution source materials. Dry deposition calculation showed extensive input fluxes of Sr, Zn, Cr, U, Ni and Cd. Significant correlation was established between measured trace elements concentrations and their calculated deposition fluxes. Phosphorus species were the principal carriers of trace elements in soils. The phosphate industry poses a serious soil pollution hazard, with deposited contaminants being potentially hazardous to plants and groundwater. This study serves as a basis to assess the phosphate industry's risk impact on soil, while it introduces combined analytical methodologies for such assessment.