Environmental assessment and management of phosphogypsum according to European and United States of America regulations

Abstract

Waste derived from fertilizer production has been accumulated worldwide for decades, especially during the last century. This waste is mainly formed by phosphogypsum; a mixture of gypsum along with phosphates, fluorides, and organic matter, which are generated from phosphoric acid production. Phosphogypsum deposits are usually associated with an important load of radionuclides and metals. The present study aims to evaluate and compare the hazard derived from the metals leaching with phosphogypsum deposits located in areas under US and European environmental regulations. Archived samples from Mulberry (USA) and field samples from Huelva (Spain) deposits have been characterized by leaching tests, as outlined in the aforementioned regulations. The obtained results have been collated with EN 12457-2 from the European regulation and TCLP from the US EPA. As a result, Mulberry phosphogypsum was classified as non-hazardous by both regulations. Since the regulations differ on their strictness, only the European regulation classifies the Huelva deposit as hazardous for As and Cd, urging to have monitoring measurements; while the US regulation classifies the deposit as non-hazardous, even though a pre-treatment before depositing is recommended.