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Donald L. Sparks
University of Delaware
458Publications
78H-index
28.4kCitations
Publications 458
Newest
#1Steven A. Banwart (University of Leeds)H-Index: 36
#2Nikolaos P. Nikolaidis (TUC: Technical University of Crete)H-Index: 29
Last.Donald L. Sparks (UD: University of Delaware)H-Index: 78
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Soil is the central interface of Earth's critical zone—the planetary surface layer extending from unaltered bedrock to the vegetation canopy—and is under intense pressure from human demand for biom...
#1Qian Sun (CAS: Chinese Academy of Sciences)H-Index: 19
#2Cun Liu (CAS: Chinese Academy of Sciences)H-Index: 18
Last.Wei Li (NU: Nanjing University)H-Index: 20
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Abstract Apart from surface complexation, precipitation of minerals also plays an important role in reducing the mobility and transport of heavy metals in the environment. In this study, Cd(II) sorption species on surfaces of γ-Al 2 O 3 at pH 7.5 were characterized using multiple techniques. Results show that in addition to adsorption complexes, Cd hydroxide phases (Cd(OH) 2 precipitates and Cd x (OH) y polynuclear complexes) were formed at the initial stages of Cd(II) sorption and gradually tra...
#1Tyler D. Sowers (UD: University of Delaware)H-Index: 2
#2Kathryn L. Holden (UD: University of Delaware)
Last.Donald L. Sparks (UD: University of Delaware)H-Index: 78
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Iron (oxyhydr)oxides are highly reactive, environmentally ubiquitous organic matter (OM) sorbents that act as mediators of terrestrial and aqueous OM cycling. However, current understanding of environmental iron (oxyhydr)oxide affinity for OM is limited primarily to abiogenic oxides. Bacteriogenic iron (oxyhydr)oxides (BIOs), common to quiescent waterways and soil redox transitions, possess a high affinity for oxyanions (i.e., arsenate and chromate) and suggests that BIOs may be similarly reacti...
#1Yilu Xu (Swansea University)H-Index: 7
#2Balaji Seshadri (University of Newcastle)H-Index: 13
Last.Tony Hall (University of Adelaide)H-Index: 2
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Abstract Soil microorganisms are an important indicator of soil fertility and health. However, our state of knowledge about soil microbial activities, community compositions and carbon use patterns under metal contaminations is still poor. This study aimed to evaluate the influences of heavy metals (Cd and Pb) on soil microorganisms by investigating the microbial community composition and carbon use preferences. Metal pollution was approached both singly and jointly with low (25 and 2500 mg kg −...
#1Olesya Lazareva (UD: University of Delaware)H-Index: 4
#2Donald L. Sparks (UD: University of Delaware)H-Index: 78
Last.Jing Ma (UW: University of Waterloo)H-Index: 1
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Mercury (Hg) was used during 1929–1950 as a catalyst to produce rayon acetate at the former DuPont plant in Waynesboro, Virginia, and released into the South River. Though the use of Hg ceased in the 1970s, the affected ecosystem is still a matter of concern. Here, high total mercury (THg) and total organomercury, stated as methylmercury (MeHg) are reported in historically contaminated floodplain soils and shallow groundwater from five locations sited 5.6 km downstream from the plant of one rive...
#1Sabry M. Shaheen (University of Wuppertal)H-Index: 25
#2Daniel S. Alessi (U of A: University of Alberta)H-Index: 21
Last.Jörg Rinklebe (Sejong University)H-Index: 34
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Abstract Vanadium (V), although serving as an important component of industrial activities, has bioinorganic implications to pose highly toxic hazards to humans and animals. Soils and sediments throughout the world exhibit wide ranges of vanadium concentrations. Although vanadium toxicity varies between different species, it is mainly controlled by soil redox potential (E H ). Nonetheless, knowledge of the redox geochemistry of vanadium lags in comparison to what is known about other potentially...
#1Beatrice GiannettaH-Index: 2
#2Claudio Zaccone (University of Foggia)H-Index: 21
Last.Donald L. Sparks (UD: University of Delaware)H-Index: 78
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Abstract Soil organic matter (SOM) protection, stability and long-term accumulation are controlled by several factors, including sorption onto mineral surfaces. Iron (Fe) has been suggested as a key regulator of SOM stability, both in acidic conditions, where Fe(III) is soluble, and in near-neutral pH environments, where it precipitates as Fe(III) (hydr)oxides. The present study aimed to probe, by sorption/desorption experiments in which Fe was added to the system, the mechanisms controlling Fe(...
#1Elizabeth K. Coward (UD: University of Delaware)H-Index: 4
#2Tsutomu Ohno (UMaine: University of Maine)H-Index: 28
Last.Donald L. Sparks (UD: University of Delaware)H-Index: 78
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While the importance of organic matter adsorption onto reactive iron-bearing mineral surfaces to carbon stabilization in soils and sediments has been well-established, fundamental understanding of how compounds assemble at the mineral interface remains elusive. Organic matter is thought to layer sequentially onto the mineral surface, forming molecular architecture stratified by bond strength and compound polarity. However, prominent complexation models lack experimental backing, despite the role...
#1Yu-Jun Wang (CAS: Chinese Academy of Sciences)H-Index: 25
#2Ting-Ting Fan (CAS: Chinese Academy of Sciences)H-Index: 7
Last.Donald L. Sparks (UD: University of Delaware)H-Index: 78
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#1Dinesh Adhikari (UNR: University of Nevada, Reno)H-Index: 5
#2Tyler D. Sowers (UD: University of Delaware)H-Index: 2
Last.Yu Yang (UNR: University of Nevada, Reno)H-Index: 24
view all 6 authors...
Abstract Complexation with minerals plays a critical role in regulating the stability of organic matter. The presence of cations is assumed to be important for the complexation between organic matter and minerals, but there is still limited direct analysis for the formation and reactivity of mineral-organic matter-cation ternary complexes, as well as governing factors for the fate of minerals and organic matter in the complexes. In order to close this knowledge gap, we investigated the formation...
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