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The combined exposure of heavy metals and organic contaminates can influence the transport and accumulation of heavy metals within the soil-rice system. However, the underlying mechanisms of this process remain largely unknown. Herein, this study investigated the influence of three neonicotinoid insecticides (NIs), including imidacloprid (IMI), clothianidin (CLO), and thiamethoxam (THI), on the Cd transport and accumulation in rice (Oryza sativa) at different growth stages. Particular focus lied on their complex interaction and key genes expression involved in Cd transport. Results showed that the interaction between Cd and NIs was the dominant factor affecting Cd transport and accumulation in rice exposed to NIs. All three NIs chelated with Cd with nitrogen (N) on the IMI and THI nitro groups, and the N on the CLO nitro guanidine group. Interestingly, this chelation behavior varied between the tillering stage and the filling/ripening stages, resulting in diverse patterns of Cd accumulation in rice tissues. During the tillering stage, all three NIs considerably inhibited Cd bioavailability and transport to the above-ground part, lowering Cd content in the stem and leaf. The inhibition was increased with stronger chelation ability in the order of IMI (-0.46 eV) > CLO (-0.41 eV) > THI (-0.11 eV), with IMI exhibiting the highest binding energy for Cd and reducing Cd transfers from root to stem by an impressive 94.49 % during the tillering stage. Conversely, during the filling/ripening stages, NIs facilitated Cd accumulation in rice roots, stems, leaves, and grains. This was mainly attributed to the generation of nitrate ions and the release of Cd 2+ during the chelation between Cd and NIs under drainage condition. These findings provide theoretical basis for the treatment of combined contamination in field and deep insights into understanding the interaction of organic contaminants with heavy metals in rice culture process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Clay minerals are effective sorbents for toxic metal immobilization in contaminated soils and waters. However, their Cd immobilization efficiency is unclear when they are loaded with organics. In this study, sodium montmorillonite (Na-M) was successfully loaded with potassium humate, chitosan, and glycine to adsorb Cd(II) in solution. Potassium humate loaded Na-M (Na-M-HA), which had the highest specific surface area and cation exchange capacity (CEC), showed the highest Cd(II) adsorption capacity (73.7 mg g -1 ), 22.5 % and 81.8 % higher than that of chitosan loaded Na-M (Na-M-CTS) and glycine loaded Na-M (Na-M-G), respectively. The pseudo-second-order kinetic model best described (R 2  > 0.98) the adsorption kinetics of Cd(II) on the three Na-Ms, indicating that the adsorption processes were of chemisorption nature. The adsorption isotherm of Cd(II) on Na-M-HA was of the Freundlich type, suggesting multilayer adsorption. In contrast, the isothermal adsorption of Cd(II) on Na-M-CTS (R 2  = 0.99) and Na-M-G (R 2  = 0.89) was better described by the Langmuir model, suggesting the dominance of monolayer adsorption in the adsorption process. High temperature, high pH, low background ionic strength, and low valence competing cations favored Cd(II) adsorption on Na-M-HA. The underlying mechanisms of Cd(II) sorption on Na-M-HA were electrostatic attraction, ion exchange and complexation. Na-M-HA was applied to a Cd polluted soil planted with lettuce (Lactuca sativa L.). in a pot experiment. Compared to the control with no adsorbent application, Na-M-HA application at 2 % effectively reduced the available Cd content in soil and Cd accumulation in plant by 36.0 % and 56.8 %, respectively. This work demonstrated that Na-M-HA is a green, low-cost and excellent adsorbent for Cd stabilization, and that its application in Cd-polluted soils can efficiently reduce Cd bioavailability and thereby Cd transfer along the food chain and eventually reduce the threat of Cd pollution to human health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Microorganisms can modulate the contents of cadmium (Cd) and zinc (Zn) in wheat grains. Increasing the essential nutrient element Zn and decreasing the toxic element Cd in wheat grains can significantly improve human health. To characterize the specific bacterial communities associated with Cd and Zn accumulation in wheat, we conducted a field experiment by planting wheat cultivars differing in their capacity for Cd and Zn accumulation. The grain Cd contents in wheat cultivars YN23 (0.078 mg kg -1 ), JN17 (0.080 mg kg -1 ), YN836 (0.081 mg kg -1 ) and LM2 (0.091 mg kg -1 ) were significantly lower than those in ZM32 (0.16 mg kg -1 ). The Zn contents were significantly higher in the grains of JN17 (44.36 mg kg -1 ), LM2 (42.22 mg kg -1 ) and ZM32 (43.19 mg kg -1 ) than YN23 (27.05 mg kg -1 ) and YN836 (29.70 mg kg -1 ). On the basis of contents and bio-concentration factors of Cd and Zn in wheat grain, JN17 and LM2 were identified as low-Cd- and high-Zn-accumulating cultivars, YN23 and YN836 were low-Cd- and low-Zn-accumulating cultivars, and ZM23 was a high-Cd- and high-Zn-accumulating cultivar. The relative abundance values of Gemmatimonadaceae, Sphingomonadaceae and Beijerinckiaceae in the rhizospheres of low-Cd cultivars were significantly higher than those of high-Cd cultivars. High-Zn cultivars had higher abundance of Rhodanobacteraceae in the rhizosphere than did low-Zn cultivars. The low-Cd- and high-Zn-accumulating cultivars were enriched in Alphaproteobacteria and Gemmatimonadaceae, and strengthened nitrification function including aerobic_ammonia_oxidation and aerobic_nitrite_oxidation in the rhizosphere soil, thus contributing to the decreased Cd and increased Zn contents in wheat grains. Microbial technology is a promising method to control the contents of Cd and Zn in wheat grains., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)