Year: 2025
Type: article
Abstract: Rice is one of the world’s most consumed foods, and the cereal that most efficiently uptakes and accumulates As, contributing to human health risk. Flooded rice fields alter Eh-pH conditions and, consequently, the proportion of As(III)/As(V), favoring their accumulation in the crop. The use of algae in paddy soils can improve fertility and C-stock and affect chemical conditions and As availability. This study aimed to evaluate the effect of algae application on: As adsorption capacity in paddy soils from Sado, Portugal, changes in pH-Eh conditions in the soil–water environment, and consequent As speciation. Batch-based As adsorption assays were performed with different solid–solution ratios and Chlorella minutissima algae application, and fitted to the Freundlich and Langmuir linear models. In semi-continuous column assays, simulating rice field conditions, the effect of algae on the pH-Eh of soil pore water was evaluated. The soil quality assessment showed pseudo-total contents of As and other elements higher than Portuguese agriculture limits (11 mg As kg−1), but their availability was low, posing no environmental risk. The studied soils had great As adsorption, which increased with algae application (1.07 mg g−1). Algae application favored oxygenation, increasing Eh values, and maintaining As(V) species. This indicated a potential approach to reducing As(III) mobility.
Source: Soil Systems
Institutions: University of Lisbon, Laboratório Associado TERRA
Language: English
Subfield: Environmental Chemistry
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,172
OpenAlex ID: W4414516720