Magnesium slag for remediation of cadmium‐ and arsenic‐contaminated paddy soil: A field study

Abstract

The accumulation of heavy metals like cadmium (Cd) and metalloids like arsenic (As) in plants can do harm to human health through the food chain, especially through the rice (Oryza sativa L.). To solve this problem, this study researched the application of magnesium slag (MS) and polyaspartic acid (PASP), which could accelerate rice growth and improve yield, increase soil pH and activate rice enzyme activity as well as reduce the bioavailability of Cd and As in the soil. After these two different treatments, rice yield increased by 17.0% and 18.9%, respectively. Meanwhile, the bioavailable As decreased by 49.1% and 42.5%, while the bioavailable Cd reduced by 72.6% and 44.3%. Besides, the Cd content in rice grains reduced by 77.7% and 17.3%, respectively, after two different treatments. In the MS treatment, the As content in rice grains was reduced by 21.8%, but showed no significant response to the other treatment. The contents of bioavailable Cd and As (determined by one‐step extraction) in soil were decreased by MS and PASP, which was favourable for the reduction of Cd and As accumulation in rice. The health risk assessment showed that the application of passivators can effectively reduce the risk of carcinogenesis, but it was still unacceptable. The application dose of MS and PASP still needs further exploration.

Biochar amendment gradually immobilized soil As and Sb over 2 years

“…This phenomenon provides direct evidence of the liming effect induced by biochar amendment, which will lead to the immobilization of cations including Cd and Pb theoretically (Bolan et al., 2014; Palansooriya et al., 2020). This pH increase may also explain the initial mobilization or very poor immobilization effect observed for As, given that As is known to mobilize more readily in alkaline environments compared with acidic soils (Alloway, 2012; Gao et al., 2022; Zhang, Tan, et al., 2022). In contrast, an increase in soil pH had less impact on Sb immobilization.…”

Soil health and ecosystem services

“…Heavy metals such as cadmium in agricultural soil represents one of the biggest threats to human health (Arao et al, 2010; Qin et al, 2023), and crops have particularly high rates of cadmium uptake (Dong et al, 2022; Zhang, Tan, et al, 2022). Open burning of contaminated straw or its usage as livestock feed can further increase exposure risks via inhalation or ingestion of meat and milk.…”

Structural Characteristics and Cementitious Behavior of Magnesium Slag in Comparison with Granulated Blast Furnace Slag

“…The effect of volumetric instability can be eliminated after carbonation for 2 h. At the same time, carbonation treatment can quickly obtain higher compressive strength, reaching 90 MPa at 24 h [26]. The incorporation of magnesium slag can improve the soil environment by granularizing the soil and providing higher cementitious activity [27][28][29], and also has a remediation effect on Cd-and Ascontaminated paddy soils [30]. Jia et al [31] investigated the desulfurization characteristics of magnesium slag and achieved a calcium conversion of 30.3% for samples treated with continuous hydration under optimum process parameters.…”