Sulfur (S)-induced enhancement of iron plaque formation in the rhizosphere reduces arsenic accumulation in rice (Oryza sativa L.) seedlings

Hu, Zhengyi; Zhu, Yan; Li, Min; Zhang, Li-Gan; Cao, Zhaoliang; Smith, F. A.

doi:10.1016/j.envpol.2006.06.014

Cited by 165 publications

(71 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These results are inconsistent with previously reported effectiveness of S additions in limiting As uptake from hydroponic and As-spiked sand/soil systems [44][45][46]54]. It is possible that the sulfate levels applied in this study were insufficient to profoundly impact the As mobility from soil to grain, although in Hu et al (2007) [46] a smaller (30 mg kg-1) sulfate addition did decrease As content in rice shoots. We intentionally selected soils that should be S sufficient for rice, in order to specifically study the effect of adding excess sulfate.…”

Section: Discussioncontrasting

confidence: 57%

“…In fact, it is possible that the gypsum treatment was ineffective partly because it decreased the formation of Fe plaque in these soils (Table 1). Previous studies have shown both increased [45,46] and decreased [60,61] plaque with S additions, possibly dependent on the amount of S added [60]. Thus, we hypothesize that the indicated importance of Fe for As concentration in rice grain, in fact, provides an explanation for the limited impact of S on As uptake in this study.…”

Section: Discussionmentioning

confidence: 55%

See 1 more Smart Citation

Relevance of Reactive Fe:S Ratios for Sulfur Impacts on Arsenic Uptake by Rice

Boye

Lezama‐Pacheco

Fendorf

2017

Soils

View full text Add to dashboard Cite

Human arsenic exposure from rice consumption is a global concern. Due to the vast areas of naturally contaminated soils in rice-producing regions, the only possibility for reducing hazardous exposure is to prevent As uptake and translocation to rice grain. Sulfur inhibits As mobility both in soil and plant, indicating that soil S content may be a primary factor controlling As uptake; indeed, gypsum (CaSO 4 ·H 2 O) has been proposed as a potential amendment. Here, we investigated S controls on rice As uptake within two naturally contaminated soils (15.4 and 11.0 mg As per kg soil, respectively) from Cambodia, by adding gypsum at two levels (20 and 60 mg per kg soil). We found that although gypsum initially decreased As release to soil solution, the concentrations then increased compared to the control treatment. Further, As concentrations in rice biomass were generally insignificantly affected by the gypsum treatments and trended in opposite directions between the two soils. Single and multivariate statistical tests indicated that Fe exerted stronger control on As uptake in rice than S and that the initial ratio of reactive Fe to sulfate-S had an overriding impact on As uptake in rice. However, in the soil with higher inherent sulfate content (91 mg SO 4 2− -S per kg soil) the additional S provided by gypsum appeared to increase the ability of the rice plant to prevent As translocation to grain. We conclude that S may contribute to regulating grain As concentrations, but that the effect is highly dependent on S:Fe(As) ratios. Thus, at modest amendment rates, gypsum has limited potential for minimizing As concentration in rice when applied to naturally contaminated soil, particularly if the reactive Fe(III) content is high.

show abstract

Section: Discussioncontrasting

confidence: 57%

Section: Discussionmentioning

confidence: 55%

Relevance of Reactive Fe:S Ratios for Sulfur Impacts on Arsenic Uptake by Rice

Boye

Lezama‐Pacheco

Fendorf

2017

Soils

View full text Add to dashboard Cite

show abstract

“…The release of As to soil solution and its accumulation in rice plants in the transition from oxidizing to reducing may depend on the amount of available iron and sulfur in the paddy soil, rate of reductive dissolution of Fe(III) phases, SO 4 2− reducing rate, and the rate of As precipitation with S 2− . Previous research also showed a decreased As uptake in rice plants with sulfur addition in the rice growth media (Hu et al 2007); here, we elucidated the role of sulfate reduction in limited As bioavailability in the paddy soil. This study suggests that As-contaminated paddy soil might be alleviated at low cost by stimulating microbial sulfate reduction and As precipitation in the subsurface through sulfur fertilization.…”

Section: Discussionmentioning

confidence: 79%

Arsenic bioavailability to rice plant in paddy soil: influence of microbial sulfate reduction

2015

Self Cite

View full text Add to dashboard Cite

Purpose High arsenic (As) mobility in anaerobic paddy soil due to microbial Fe-and As-reducing processes results in As accumulation into rice plants. Sulfur (S) also undergoes microbial reducing processes in the anaerobic paddy soil, while this process interacts with the Fe-and As-reducing processes, forms secondary minerals, and thus influences As mobility in paddy soil. This work was carried out to investigate the role of sulfur and sulfate-reducing bacteria (SRB) in As redox transformation and bioavailability to rice plant in an anaerobic paddy soil. Materials and methods Anaerobic incubation experiments with or without sulfate (SO 4 2− ) and SRB were carried out to monitor S and iron (Fe) dynamics and their relations to As speciation and release to soil solution. Rice cultivation in pot experiment was then carried out to check the SO 4 2− amendment in bioavailability and uptake into rice plants.Results and discussion The inoculation of an enriched SRB community into the sterilized paddy soil increased reduction and release of As to the soil solution after flooding, showing its ability in arsenate (As(V)) as well as SO 4 2− reduction to arsenite (As(III)) and sulfide (S 2− ), respectively. Sulfate addition (2 and 100 mM) into the anaerobic paddy soil increased the reduction of SO 4 2− and ferric iron (Fe 3+ ) and resulted to lower dissolved As in the soil solution, which limited As mobility in the paddy soil. Application of SO 4 2− (100 mg kg −1 ) into paddy soil finally decreased the concentration of dissolved As in the soil solution by 23.5 % and also decreased As content in rice roots and iron plaque by 22.6 and 30.5 %, respectively. Conclusions The results revealed the important role of sulfur and the SRB activity in As speciation and mobility in anaerobic paddy soil, implying a lower As bioavailability to rice plants under sulfur-enriched anaerobic paddy soil, and an efficient way to reduce As accumulation in rice plants by sulfur fertilization in paddy soils.

show abstract

“…Among them, organic acids are by far the most abundant and the most reactive with metals (Laheurte et al, 1990;Pomilio et al, 2000). Researchers have found that low-molecular-weight organic acids in the rhizosphere are capable of forming complexes with metal ions in solution and thus enhance the metals' mobilization and uptake by plants (Mench and Martin, 1991;Awad et al, 1994;Krishnamurti et al, 1997;Veeken and Hamelers, 1999;Chen et al, 2003;Gao et al, 2003;Hu et al, 2007;Luo et al, 2008). Feng et al (2005) showed that the extractable amount of Cr, Cu, Zn and Cd by the root exudes correlated significantly with the metal content of barley roots, while the extractable metals identified by DTPA, EDTA, CaCl 2 and NaNO 3 methods exhibited relatively poor or no correlation with the metal content of barley roots.…”

Section: Introductionmentioning

confidence: 99%