The geochemical evolution of brines from phosphogypsum deposits in Huelva (SW Spain) and its environmental implications

Roy Nir Lieberman, Maria Izquierdo, Patricia Córdoba, Natalia Moreno Palmerola, Xavier Querol, Ana M. Sánchez de la Campa, Oriol Font, Haim Cohen, Yaniv Knop, Raquel Torres-Sánchez, Daniel Sánchez-Rodas, Carmen Muñoz-Quiros, Jesús D. de la Rosa

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

The present study focuses on the geochemistry of large phosphogypsum deposits in Huelva (SW Spain). Phosphogypsum slurry waste from fertiliser production was disposed in large ponds containing aqueous waste (i.e. brines) and exposed to weathering. These evaporation ponds were found to be dynamic environments far from attaining steady state conditions where a number of trace pollutants are subjected to temporal variations in response to changing environmental conditions. Chemical, mineralogical and morphological data were used to improve our understanding on the dynamics of a large number of elements in the phosphogypsum-brine-evaporation deposits system. Weekly sampling of brines over the course of 1 yr indicated a substantial enrichment in potentially harmful elements (e.g. As, Cr, Cu, F, Ni, U, V, Zn) present in time-dependent concentrations. The evaporation deposits formed multi-layered precipitates of chlorides, sulphates, phosphates and fluorides containing a large number of pollutants in readily soluble forms. The precipitation sequence revealed a time-dependent composition reflecting alternating precipitation and re-dissolution processes associated with seasonal changes in the local weather conditions. Concatenation of precipitation/re-dissolution stages was found to progressively enrich the brines in pollutants. These findings were supported by the observations from a tank experiment simulating the phosphogypsum-brine-evaporation deposits system under laboratory conditions. Given the substantially high concentrations of pollutants present in mobile forms in the brine-salt system, actions to abate these compounds should be implemented.

Original languageEnglish
Article number134444
JournalScience of the Total Environment
Volume700
DOIs
StatePublished - 15 Jan 2020
Externally publishedYes

Keywords

  • Brine
  • Evaporation pond
  • Hazardous waste
  • Heavy metals
  • Phosphogypsum

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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