Influence of pH on the Particulate-Bound Cd Speciation and Uptake by Plants

Abstract

The speciation of heavy metals in soil is a better indicator for assessing the bioavailability than the total concentration. Soil pH is a vital factor influencing the particulate-bound metal speciation and the metal dynamics at rhizosphere soil-root interface. In this study, greenhouse pot experiment was conducted to reveal the influence of pH on the speciation of cadmium (Cd) in solid phase of soil and the amount of Cd uptake by different ecotype plants. The results illustrated that the exchangeable Cd decreased obviously with the increase of soil pH, while the residual Cd displayed the reverse. The amount of Cd uptake by plants increased with pH decreased, and pH 5.5 exhibited the optimum for plants growth and metal uptake. Furthermore, the biomass and uptake capability of the hyperaccumulator plants (Sedum alfredii and Beta vulgaris var. cicla L with red leaves) were higher than the corresponding non-hyperaccumulator plants. Results indicated that the pH decrease and rhizosphere effects of hyperaccumulator could facilitate the activation of Cd and enhance the phytoremediation efficiency significantly.

Synergistic Phytoremediation of Cadmium-Contaminated Soil: Intercropping Rapeseed and Kenaf for Enhanced Biomass, Metal Uptake, and Soil Health

“…The decrease in soil pH was observed in all soil Cd treatments in intercropping. The ndings of our study align with previous research, which demonstrated that a decrease in soil pH leads to an increase in the bioavailability of Cd (Lian et al, 2022) and is the key reason for the greater root Cd uptake and higher Cd concentration in aboveground plant parts (Tsadilas et al, 2005;Zou et al, 2023). Bian et al (2021) found that intercropping bamboo and Sedum plumbizincicola led to an increase in biomass and a decrease in soil pH, which facilitated the removal of heavy metals from the soil.…”

Insight into chromium adsorption from contaminated soil using Mg/Al LDH-zeolite

“…Soil pH is a critical factor influencing HMs' chemical speciation and bioavailability in the CS [ 26 ]. Fig.…”

Impacts of irrigation with Cd-contaminated water from Sugovushan Reservoir, Azerbaijan on total cadmium and its fractions in soils with varied textures

“…In the incubation experiment, although initially the entire set of soils used exhibited the CFeO-Cd fraction as the predominant fraction within inorganic Cd fractions, it was observed that OM-Cd and Res.-Cd contained the least Cd fraction (Figure 1). Numerous studies have demonstrated the influence of various soil physicochemical properties such as soil texture, organic matter content, and pH on the distribution of inorganic Cd fractions in soils (Anju and Banerjee, 2011;Nejad et al, 2021;Lian et al, 2022). Kızılkaya and Aşkın (2002), in their investigation of the distribution of Cd fractions and the relationships between soil properties in agricultural fields in the Bafra Plain of Turkey, determined that the total Cd content in alluvial soils ranged from 1.83 to 2.73 mg kg -1 .…”