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Impacts of Hazardous Air Pollutants Emitted from Phosphate Fertilizer Production Plants on their Ambient Concentration Levels in the Tampa Bay Area
Citation:
Li, H., N. Afshar-Mohajer, C. Wu, J. Bonzongo, V. Ilacqua, Y. Choi, AND B. Birky. Impacts of Hazardous Air Pollutants Emitted from Phosphate Fertilizer Production Plants on their Ambient Concentration Levels in the Tampa Bay Area. Air Quality, Atmosphere & Health. Springer Netherlands, , Netherlands, 8(5):453-467, (2014).
Impact/Purpose:
Florida phosphate contributes approximately half of US farmers’ supply of phosphate fertilizer and 20% of the global supply (Florida Phosphate 2010). Currently, there is insufficient knowledge about the airborne metal HAPs emissions from phosphate fertilizer plants and their impact. Without such knowledge, conservative estimates must be used for public health protection and add unnecessary processes that may not meaningfully lower the levels and distribution of HAPs in air. Therefore, a study aiming to understand the impact of these production processes on the levels and distribution of these metal HAPs emissions in atmosphere is of critical need to provide guidelines for environmental agencies as well as plant managers.
Description:
The concentrations and distribution of Hazardous Air Pollutants (HAPs) metals emitted from four phosphate fertilizer plants in Central Florida, as well as their environmental and health impacts, were assessed. The dominant HAP metals emitted from the stacks of these plants were Mn, Cr, Ni and Se. The ambient concentrations at six receptors (Zephyrhills, Plant City, Tampa, Lakeland, Tower Dairy and Sydney) downwind the plants estimated by AERMOD revealed the highest level was at Tower Dairy. For metals with existing standards, the maximum ground level concentrations were lower than the European Communities and USEPA standards. Source apportionment estimated by the Chemical Mass Balance (CMB) model for the Tower Dairy site indicated that marine (45.5±17.1%) and geological (17.3±10.6%) were the top two contributors for 26 elements, while the phosphate fertilizer plants contributed only 1.14±0.55%. The maximum ground-level risks for Cr from Plant A (1.3×10-6 ± 8.4×10-8) and Plant D (1.1×10-6 ± 6.7×10-8) were slightly higher than the general guideline of 1×10-6, but they occurred within the facility limit. No other metals approached levels of concern for non-cancer risks. One possible source for Cr emissions from these plants may be stainless steel milling balls used in the production process. Sensitivity analysis of the meteorological data in 2001-2005 showed only 7.7% variation in the corresponding risk. Overall, phosphate fertilizer plants make minor contribution to the ambient concentration levels of HAP metals compared to other sources in the Tampa Bay area, although more in-depth investigation into the Cr emissions is recommended.
