Sustaining Irrigation Supplies through Immobilization of Groundwater Arsenic In Situ.
Environ Sci Technol
; 58(28): 12653-12663, 2024 Jul 16.
Article
en En
| MEDLINE
| ID: mdl-38916402
ABSTRACT
Geogenic arsenic (As) in groundwater is widespread, affecting drinking water and irrigation supplies globally, with food security and safety concerns on the rise. Here, we present push-pull tests that demonstrate field-scale As immobilization through the injection of small amounts of ferrous iron (Fe) and nitrate, two readily available agricultural fertilizers. Such injections into an aquifer with As-rich (200 ± 52 µg/L) reducing groundwater led to the formation of a regenerable As reactive filter in situ, producing 15 m3 of groundwater meeting the irrigation water quality standard of 50 µg/L. Concurrently, sediment magnetic properties were markedly enhanced around the well screen, pointing to neo-formed magnetite-like minerals. A reactive transport modeling approach was used to quantitatively evaluate the experimental observations and assess potential strategies for larger-scale implementation. The modeling results demonstrate that As removal was primarily achieved by adsorption onto neo-formed minerals and that an increased adsorption site density coincides with the finer-grained textures of the target aquifer. Up-scaled model simulations with 80-fold more Fe-nitrate reactants suggest that enough As-safe water can be produced to irrigate 1000 m2 of arid land for one season of water-intense rice cultivation at a low cost without causing undue contamination in surface soils that threatens agricultural sustainability.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Arsénico
/
Contaminantes Químicos del Agua
/
Agua Subterránea
/
Riego Agrícola
Idioma:
En
Revista:
Environ Sci Technol
Año:
2024
Tipo del documento:
Article
País de afiliación:
China