[Screening for the Priority Crops in Over-standard Planting Region Based on the Difference in Arsenic and Cadmium Accumulated in Crops].

Conducting the screening and replanting of crops with low accumulation of heavy metals can effectively reduce the risk of heavy metal accumulation in agricultural products. However, current research focuses more on the screening of crops with low accumulation of a single heavy metal. Target crops also focus more on single-type crops and varieties.

Effective co-immobilization of arsenic and cadmium in contaminated soil by sepiolite-modified nano-zero-valent iron and its impact on the soil bacterial community.

Sepiolite-modified nano-zero-valent iron (S-nZVI) is used as an amendment and incubated to remediate As-Cd-contaminated soil under three different soil‒water management conditions [moderately wet (MW), continuously flooded (CF) and alternately wet and dry (AWD)]. The results showed that soil pH is in the order of CF > AWD > MW. The soil pH increased approximately 0.

Purifying selection drives distinctive arsenic metabolism pathways in prokaryotic and eukaryotic microbes.

Microbes play a crucial role in the arsenic biogeochemical cycle through specific metabolic pathways to adapt to arsenic toxicity. However, the different arsenic-detoxification strategies between prokaryotic and eukaryotic microbes are poorly understood. This hampers our comprehension of how microbe-arsenic interactions drive the arsenic cycle and the development of microbial methods for remediation.

Water-fertilizer regulation drives microorganisms to promote iron, nitrogen and manganese cycling: A solution for arsenic and cadmium pollution in paddy soils.

The co-contamination of arsenic (As) and cadmium (Cd) in rice fields presents a global imperative for resolution. However, understanding the complex microbially driven geochemical processes and network connectivity crucial for As and Cd bioavailability under the frequent redox transitions in rice fields remains limited. Here, we conducted a series of microcosm experiments, using flooding and drainage, alongside fertilization treatments to emulate different redox environment in paddy soils.

A review of amendments for simultaneously reducing Cd and As availability in paddy soils and rice grain based on meta-analysis.

Arsenic (As) and cadmium (Cd) accumulation in rice grains is a global food safety issue, and various methods and materials have been used to remove or reduce As and Cd in agricultural soils and rice grains. Despite the availability of synthesized materials capable of simultaneous As and Cd reduction from soil and rice grains, the contributions, efficiency, and main ingredients of the materials for As and Cd immobilization remain unclear. The present study first summarized the biogeochemistry of As and Cd in paddy soils and their transfer in the soil-food-human continuum.

Metal-Binding Protein TaGlo1 Improves Fungal Resistance to Arsenite (As) and Methylarsenite (MAs) in Paddy Soil.

Trivalent arsenicals such as arsenite (As) and methylarsenite (MAs) are thought to be ubiquitous in flooded paddy soils and have higher toxicity than pentavalent forms. Fungi are widely prevalent in the rice rhizosphere, and the latter is considered a hotspot for As uptake. However, few studies have focused on alleviating As toxicity in paddy soils using fungi.

Soil ridging combined with biochar or calcium-magnesium-phosphorus fertilizer application: Enhanced interaction with Ca, Fe and Mn in new soil habitat reduces uptake of As and Cd in rice.

Reducing the bioavailability of both cadmium (Cd) and arsenic (As) in paddy fields is a worldwide challenge. The authors investigated whether ridge cultivation combined with biochar or calcium-magnesium-phosphorus (CMP) fertilizer effectively reduces the accumulation of Cd and As in rice grains. Field trial showed that applying biochar or CMP on the ridges was similar to the continuous flooding, which maintained grain Cd at a low level, but grain As was reduced by 55.

Differential responses of canonical nitrifiers and comammox to long-term fertilization in an Alfisol of Northeast China.

The newly identified complete ammonia oxidizer (comammox) that converts ammonia directly into nitrate has redefined the long-held paradigm of two-step nitrification mediated by two distinct groups of nitrifiers. However, exploration of the niche differentiation of canonical nitrifiers and comammox and their ecological importance in agroecosystems is still limited. Here, we adopted quantitative PCR (qPCR) and Illumina MiSeq sequencing to investigate the effects of five long-term fertilization regimes in the variations of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), nitrite-oxidizing bacteria (NOB), and comammox abundances and comammox community composition in two soil layers (0-20 cm, topsoil; 20-40 cm, subsoil) in an Alfisol in Northeast China.

Responses of potential ammonia oxidation and ammonia oxidizers community to arsenic stress in seven types of soil.

Soil arsenic contamination is of great concern because of its toxicity to human, crops, and soil microorganisms. However, the impacts of arsenic on soil ammonia oxidizers communities remain unclear. Seven types of soil spiked with 0 or 100 mg arsenic per kg soil were incubated for 180 days and sampled at days 1, 15, 30, 90 and 180.

Thermodynamics, Kinetics, and Mechanisms of the Co-Removal of Arsenate and Arsenite by Sepiolite-Supported Nanoscale Zero-Valent Iron in Aqueous Solution.

In this study, a newly synthesized sepiolite-supported nanoscale zero-valent iron (S-nZVI) adsorbent was tested for the efficient removal of As(III) and As(V) in aqueous solution. Compared with ZVI nanoparticles, the As(III) and As(V) adsorption abilities of S-nZVI were substantially enhanced to 165.86 mg/g and 95.

[Arsenic Methylation Efficiency Changes During Paddy Soil Drying and Its Key Influencing Factors Analysis].

The straight head disease of rice is one of the main problems limiting rice production. Arsenic (As) methylation in paddy soils is considered to be highly related to the occurrence of the straight head disease. As a typical field practice, rice fields are usually drained during the late tillering stage and the mid-late grain filling stage.

Synergistic removal of As(III) and Cd(II) by sepiolite-modified nanoscale zero-valent iron and a related mechanistic study.

Arsenic (As) and cadmium (Cd) are two highly toxic elements. In recent years, many newly synthesized chemical materials have been used widely for treatments of As- and Cd-contaminated effluents. However, most materials do not exhibit high efficiencies for simultaneous removal of As and Cd from water systems.

Influence of straw-derived humic acid-like substance on the availability of Cd/As in paddy soil and their accumulation in rice grain.

Humic acid amendments have been widely advocated for the remediation of heavy metal-contaminated soil. However, the impacts of straw-derived humic acid-like substances on the remediation of cadmium (Cd) and arsenic (As) co-contaminated paddy soil remain unclear and the potential mechanism required clarification. In this study, we employed a pot experiment and chose a straw-derived humic acid-like substance (BFA) as the amendment with four doses to investigate how BFA affects the availability of Cd and As in soil and their accumulation in rice.

The performance and mechanism of cadmium availability mitigation by biochars differ among soils with different pH: Hints for the reasonable choice of passivators.

The performances of passivation materials mitigating Cadmium (Cd) bioavailability considerably vary with the pH condition of Cd-contaminated soils. However, less information was available for the method of improving Cd passivation efficiency taking into account the pH of the targeted soil. Furthermore, the underlying mechanism of Cd availability mitigation in soils with different pH has not been clearly explored.

Soil ridge cultivation maintains grain As and Cd at low levels and inhibits As methylation by changing arsM-harboring bacterial communities in paddy soils.

The simultaneous mitigation of toxic arsenic (As) and cadmium (Cd) in rice grain remains a global challenge. The over-accumulation of husk dimethylarsinic acid (DMAs) induces the rice straight-head disease, which threatens rice production worldwide. In this study, we investigated various soil ridge height treatments with Eh ranging from - 225-87 mV and pH ranging from 6.

Effect of humic and calcareous substance amendments on the availability of cadmium in paddy soil and its accumulation in rice.

Humic substances (HS) are widely known as important components in soil and significantly affect the mobility of metals due to their large surface area and abundant organic functional groups. Calcareous substances (CSs) are also commonly used as robust and cost-effective amendments for increasing the pH of acidic soils and decreasing the mobility of metals in soils. In this study, we developed a new remediation scheme for cadmium (Cd)-contaminated soil remediation by coupling HS and CS.

Simultaneous mitigation of Cd and As availability in soil-rice continuum via the addition of an Fe-based desulfurization material.

The simultaneous mitigation of toxic arsenic (As) and cadmium (Cd) in rice grain remains a global challenge. Passivation with natural or artificially modified materials has shown great potential to simultaneously reduce the bioavailability of As and Cd in paddy soils. To date, however, limited materials have are available, with unclear underling mechanisms.

The stability of poorly crystalline arsenical ferrihydrite after long-term soil suspension incubation.

2- Line ferrihydrite (Fh) is widely used as a robust amendment for rapid arsenic removal or remediation in water or soil. However, the poorly crystalline phase of Fh is unstable and leads to arsenic leaching after long-term submergence in reductive aquatic and soil environments. In this study, the synthesized As(V)-bound Fh was characterized by various spectral approaches to investigate the factors that may affect the variation in As(V)-Fh in long-term continuously submerged soil suspensions.

Cadmium and arsenic availability in soil under submerged incubation: The influence of humic substances on iron speciation.

Humic substances (HSs), as electron shuttles, are associated with iron oxide transformation, yet the manner by which HSs affect Cd/As availabilities during this process under anaerobic conditions remains unclear. Two HSs (humic sodium, HA-Na, and biochemical fulvic acid, BFA) were applied at 0, 1, 2, and 4 gCkg in a submerged incubation experiment. The dissolved, extractable and fractions of Cd/As and different iron oxides in soils were monitored.

Exogenous fulvic acid enhances stability of mineral-associated soil organic matter better than manure.

Mineral-associated soil organic matter (MAOM) is seen as the key to soil carbon sequestration, but its stability often varies with types of exogenous organic materials. Fulvic acid and manure are ones of the exogenous organic materials used for the improvement of degraded soil. However, little is known about if and how fulvic acid and manure affect the stability of MAOM.

[Comparison in cadmium accumulation capacities of different leafy vegetables through cadmium-rich substrate cultivation].

To acquire a feasible method for a rapid comparison of the cadmium (Cd) accumulation capacities of different leafy vegetables, using substrate cultivation with different contents of Cd and cultivation time, we compared the observed Cd accumulation capacity with these obtained in the field. The results showed that the Cd content and bio-concentration factors (BCFs) value in the aboveground tissue of leafy vegetable varied significantly with Cd content and cultivation time. Multi-factor analysis of variance showed that vegetable variety, cultivation time, Cd content in substrate and their interaction had significant effects on BCFs of Cd in leafy vegetable.

Contradictory tendency of As(V) releasing from Fe-As complexes: Influence of organic and inorganic anions.

The strong ability of ferrihydrite and its aged minerals for fixing arsenate is a key factor in remediating arsenate-polluted environments. It is therefore crucial to clarify the stability of Fe-As complexes and the release conditions for As(V). The As(V) release amount was evaluated and compared in the presence of six representative anions, namely, phosphate, silicate, sulfate, inositol hexaphosphate, citrate, and oxalate.

Effects of green manure planted in winter and straw returning on soil aggregates and organic matter functional groups in double cropping rice area.

To explore the mechanism of exogenous organic materials enhancing soil organic carbon and soil fertility, based on a long-term experiment located in Hengyang Red Soil Experimental Station, we examined the effects of winter green manure and straw returning patterns (CK, winter fallow; MV, winter Chinese milk vetch; S, early-season rice straw total returning; DS, early-season and late-season rice straw total returning; SMV, winter Chinese milk vetch + early-season rice straw total returning; DSMV, winter Chinese milk vetch + early-season and late-season rice straw total returning) on soil aggregates and organic functional groups. The results showed that the proportion of super aggregates (>2 mm) and macroaggregates (0.25-2 mm) in double cropping rice soil was the highest with a ratio of about 72.

Seeking for an optimal strategy to avoid arsenic and cadmium over-accumulation in crops: Soil management vs cultivar selection in a case study with maize.

Soil management and cultivar selection are two strategies to reduce the accumulation risk of heavy metals in crops. However, it is still an open question which of these two strategies is more efficient for the safe utilization of contaminated soil. In this study, the available bio-concentration factors (aBCF) of arsenic (As) and cadmium (Cd) among 39 maize cultivars were determined through a field experiment.

Effects of composited organic mobilizing agents and their application periods on cadmium absorption of Sorghum bicolor L. in a Cd-contaminated soil.

Organic mobilizing agents have been advocated for phytoremediation of heavy metals contaminated soils, while the effects of application period of such agents remain unclear. A pot experiment was conducted, with two composited organic agents (oxalic acid or citric acid + dissolved organic fertilizer (OA + DOF and CA + DOF)) and four application periods (seeding, jointing, flag leaf and heading stages) of sorghum (Sorghum bicolor L.), to investigate their impacts on Cd bioavailability in soil.