Modelling Al competition for heavy metal binding by dissolved organic matter in soil and surface waters of acid and neutral pH

Tipping, E.

doi:10.1016/j.geoderma.2004.12.003

Cited by 79 publications

(50 citation statements)

References 33 publications

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“…We also assumed that both Fe III and Al III activities are controlled by the solubility of their hydroxides, as calculated using the respective empirical equations given by Lofts et al [33] and Tipping. [34] Other measured WHAM input parameters included pH and the total concentrations of Na, Mg, K, Ca, Cr, Co, Ni, Cu, Zn, Cd, Cl, NO 3 , SO 4 , CO 3 (measured as total inorganic carbon) and F. The measured surface temperature of the lakes sampled (used in the WHAM simulations) varied between 20 and 23 8C. Separate WHAM simulations were run for lake samples analysed using the IET free ion measurement method (for the analysis of free Cd 2þ , Ni 2þ and Zn 2þ ) and for those analysed with the ISE method (for the analysis of free Cu 2þ ); the input data for these simulations corresponded exactly to the composition of the samples used for the free metal ion analyses, thus accounting for the differences in their ionic composition (respective additions of Ca(NO 3 ) 2 and KNO 3 ).…”

Section: Metal Speciation Calculationsmentioning

confidence: 99%

Trace metal speciation predictions in natural aquatic systems: incorporation of dissolved organic matter (DOM) spectroscopic quality

et al. 2012

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Environmental context. To assess the risk posed by environmental contaminants such as metals, one needs to be able to identify the key chemical species that prevail in natural waters. One of the recognised stumbling blocks is the need to quantify the influence of heterogeneous dissolved organic matter (DOM). Here we explore the possibility of using the optical signature of DOM to determine its quality, to alleviate the need to make assumptions about its metal-binding properties and to improve the prediction of trace metal species distributions in natural waters.Abstract. To calculate metal speciation in natural waters, modellers must choose the proportion of dissolved organic matter (DOM) that is actively involved in metal complexation, defined here as the percentage of active fulvic acid (FA); to be able to estimate this proportion spectroscopically would be very useful. In the present study, we determine the free Cd 2þ , Cu 2þ , Ni 2þ and Zn 2þ concentrations in eight Canadian Shield lakes and compare these measured concentrations to those predicted by the Windermere Humic Aqueous Model (WHAM VI). For seven of the eight lakes, the measured proportions of Cd 2þ and Zn 2þ fall within the range of values predicted by WHAM; the measured proportion of Cu 2þ falls within this range for only half of the lakes sampled, whereas for Ni, WHAM systematically overestimated the proportion of Ni 2þ . With the aim of ascribing the differences between measured and modelled metal speciation to variations in DOM quality, the percentage of active FA needed to fit modelled and measured free metal concentrations was compared with the lake-to-lake variation in the spectroscopic quality of the DOM, as determined by absorbance and fluorescence measurements. Relationships between the percentage of active FA and DOM quality were apparent for Cd, Cu, Ni and Zn, suggesting the possibility of estimating the percentage of active FA spectroscopically and then using this information to refine model predictions. The relationships for Ni differed markedly from those observed for the other metals, suggesting that the DOM binding sites active in Cd, Cu and Zn complexation are different from those involved in Ni complexation. To our knowledge, this is the first time that such a distinction has been resolved in natural water samples.

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Section: Metal Speciation Calculationsmentioning

confidence: 99%

Trace metal speciation predictions in natural aquatic systems: incorporation of dissolved organic matter (DOM) spectroscopic quality

et al. 2012

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“…Otopljeni minerali (natrij, kloridi i sulfati) su odabrani iz razloga što su upravo navedeni ioni najučestaliji i najzastupljeniji kationi/anioni u prirodno zaslanjenim vodnim i/ili zemljišnim resursima koji se koriste u poljoprivrednoj proizvodnji, ne samo na području delte Neretve (Ondrasek et al, 2011), nego i drugim (semi)aridnim poljoprivrednim površinama (Rhoades et al, 1999). Kemijska specijacija Cd je u sva tri modela izvedena u rasponu pH od 3.5. do 9.5., što vrlo dobro korespondira pH vrijednostima većine prirodnih pedosfernih uvjeta (Tipping, 2005). Anorganska specijacija Cd je modelirana pomoću standardne termodinamičke baze i osnovnih postavki (npr.…”

Section: Materijal I Metode Radaunclassified

Procjena specijacije kadmija u saliniziranim okolišnim uvjetima

et al. 2012

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SažetakPovećanje saliniteta i sadržaja elemenata u tragovima u površini tla putem neodgovarajućih praksi gospodarenja zemljištem (fertirigacija, aplikacija kondicionera tla) predstavlja jednu od najraširenijih prijetnji sigurnosti i zaštiti hrane u suvremenoj poljoprivredi. Fitodepozicija, kao najznačajniji način unosa biotoksičnog i neesencijalnog kadmija (Cd) u ljudske namirnice, korespondira pozitivno sa salinitetom rizosfere. Pomoću kemijsko specijacijskog računalnog pristupa (Visual MINTEQ) procijenjen je biogeokemizam Cd-kontaminirane (1µM) otopine s različitim razinama (nizak-visok) jednih od najzastupljenijih prirodnih minerala (Na + 15-150, Cl -12-90 i SO 4 2-1.5-30 mM) u širokom pH (3.5-9.5) rasponu i niskom prisustvu otopljenog organskog ugljika (1 mg DOC/L). Na temelju modeliranih rezultata, koncentracija slobodnog Cd 2+ je dominirala u većini testiranog pH raspona kod niskog saliniteta, dok su u okruženju srednjeg do visokog saliniteta prevladavale koncentracije Cd-Cl-i Cd-SO 4 -kompleksiranog sadržaja Cd. NICADonnan modeliranjem je potvrđena važnost Cd-organo-kompleksiranog sadržaja jedino pri višim pH vrijednostima (>8.0) i nižem salinitetu. Rezultati potvrđuju da kao posljedica smanjenog otopljenog organskog sadržaja uslijed povećanog saliniteta (npr. prirodno salinizirana tla, vode korištene za navodnjavanje u poljoprivredi) biogeokemizam Cd u rizosferi može pospješiti mobilnost Cd, a time i njegovu fitoekstrakciju od strane navodnjavanih kultura.Ključne riječi: salinitet rizosfere, elementi u tragovima, geokemijsko modeliranje Uvod Zaslanjivanje ili salinizacija prirodnih zemljišnih i/ili vodnih resursa korištenih u poljoprivrednoj proizvodnji predstavlja jedan od najbrže rastućih problema u održivoj proizvodnji hrane (Ondrasek et al., 2011). Salinizacija obradivih površina može biti

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“…Soluble copper may precipitate or form insoluble organocomplexes at higher pH or higher levels of dissolved organic carbon. Other trace metals can sorb to organic material as well, thereby affecting the overall trace metal accumulation in soils and possible competition for available binding sites in the organic material fraction of these soils (Benedetti et al 1995;Nierop et al 2002;Tipping et al 2002;Tipping, 2005). Additionally, the EPA decided not to include iron as a pollutant in Part 503 because reports of toxicity were only observed at atypically high concentrations (Walker & Stein, 1995).…”

Section: Introductionmentioning

confidence: 99%

Mechanisms Controlling Copper Transport in Natural Soils

Luisi¹

2018

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Modelling Al competition for heavy metal binding by dissolved organic matter in soil and surface waters of acid and neutral pH

Cited by 79 publications

References 33 publications

Trace metal speciation predictions in natural aquatic systems: incorporation of dissolved organic matter (DOM) spectroscopic quality

Trace metal speciation predictions in natural aquatic systems: incorporation of dissolved organic matter (DOM) spectroscopic quality

Procjena specijacije kadmija u saliniziranim okolišnim uvjetima

Mechanisms Controlling Copper Transport in Natural Soils

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