Arsenic release from deep natural solid matrices under experimentally controlled redox conditions

► As release from two solid matrices was explored under different redox conditions. ► As content in vegetal matter is one order of magnitude larger than in sand. ► High correlation between redox conditions and As release was evidenced from the tests. ► Vegetal matter has large binding capacity and can enhance As release to groundwater. ► As concentration in groundwater depends on release from different solid matrices.