Arsenic's Interaction with Humic Acid

2005 ◽  
Vol 2 (2) ◽  
pp. 119 ◽  
Author(s):  
Peter Warwick ◽  
Edu Inam ◽  
Nick Evans
Keyword(s):  
Humic Acid ◽  
Ionic Strength ◽  
Humic Substances ◽  
Environmental Concern ◽  
Arsenic Concentration ◽  
Mining Industry ◽  
Arsenic Species ◽  
Oxide Content ◽  
Dimethylarsinic Acid ◽  
Arsenic Mobility

Environmental Context. Arsenic is of significant environmental concern in much of the world because of its contamination of waters, from mining, industry, sewage disposal, and agriculture. The environmental mobility of arsenic is controlled primarily by adsorption onto metal oxides, especially iron. Humic substances (natural organic matter), which are ubiquitous in aquatic and soil environments, may interfere with this adsorption and arsenic mobility may be increased. Thus, even if it is assumed that humic substances sorb arsenic less strongly than hydrous iron oxides, they may, nevertheless, influence arsenic sorption and mobility, particularly when the iron oxide content in the environment is low. Abstract. The environmental mobility of arsenic is primarily controlled by adsorption onto metal oxide surfaces, particularly iron, aluminium, and manganese. Humic acid (HA) may interfere with this adsorption, thereby increasing arsenic mobility. This study has characterized the interaction of arsenic with HA in a system consisting of HA with As(iii), As(v), and dimethylarsinic acid (DMAA). Three sets of batch experiments were performed at varying pH (3–12), ionic strength (0–0.4 mol dm−3), concentration of each arsenic species (0–100 mg dm−3), and HA concentration (0–10 g dm−3). Arsenic species were shown to react with humic acid. The interaction is postulated to involve bridging metals and deprotonated functional groups within the HA. The association is dependent on pH, ionic strength, and arsenic concentration. The extent of the interaction was greater in the pH range 8–10 for As(v) and DMAA, while it extended to pH 12 for As(iii). The strong pH dependency is probably due to the aqueous speciation of arsenic. The logarithmic conditional association constants for the reactions were found to be 1.97 ± 0.02, 1.58 ± 0.07, and 1.50 ± 0.10 for As(v), As(iii), and DMAA respectively. These values indicate the formation of weak complexes with humic acid.

Occurrence and Speciation of Arsenic in Common Australian Coastal Polychaete Species

2005 ◽  
Vol 2 (2) ◽  
pp. 108 ◽  
Author(s):  
Joel Waring ◽  
William Maher ◽  
Simon Foster ◽  
Frank Krikowa
Keyword(s):  
Arsenic Concentration ◽  
Habitat Type ◽  
Arsenic Species ◽  
Water Soluble ◽  
Dimethylarsinic Acid ◽  
Total Arsenic ◽  
Arsenic Compounds ◽  
Feeding Guild ◽  
Polychaete Species ◽  
Deposit Feeders

Environmental Context. In well-oxygenated water and sediments, nearly all arsenic is present as arsenate (AsO43−). As arsenate is a phosphate (PO43−) analogue, organisms living in arsenate-rich environments must acquire the nutrient phosphorus yet avoid arsenic toxicity. Organisms take in and transform arsenic compounds by many means. Three major modes of arsenic biotransformation have been found to occur in the environment—redox transformation between arsenate and arsenite (AsO2−), the reduction and methylation of arsenic, and the biosynthesis of organoarsenic compounds such as arsenobetaine. These biotransformations lead to biogeochemical cycling of arsenic compounds and bioconcentration of arsenic in aquatic organisms and thence into the food web. Abstract. The paper reports the whole-tissue total arsenic concentrations and water-soluble arsenic species in eight common coastal Australian polychaete species. Laboratory experiments showed the period of depuration did not significantly alter the whole-tissue total arsenic concentrations in the two estuarine polychaete species tested. Significant differences were found between the whole-tissue total arsenic concentrations of the eight polychaete species (mean arsenic concentrations ranged from 18 to 101 µg g−1 dry mass). Total arsenic concentrations in polychaete species, grouped on the basis of a combination of their feeding guild and habitat type, were also significantly different with a significant interaction between these factors indicating that both factors simultaneously influence arsenic concentration in polychaetes. A large number of polychaete species contained similar arsenic species with high proportions of arsenobetaine (AB; 57–88%) and relatively low proportions of As3+, As5+, methyarsonic acid, dimethylarsinic acid, arsenocholine, trimethylarsoniopropionate, and tetramethylarsonium ion (not detected to 12%). All polychaete species contained arsenoribosides (5–30%). This study identified two Australian polychaete species with particularly unusual whole-tissue water-soluble arsenic species proportions: Australonuphis parateres contained a very high proportion of trimethylarsoniopropionate (~33%), while Notomastus estuarius had a very low proportion of arsenobetaine (9%) and high proportions of As3+ (~30%), As5+ (~8%), arsenoribosides (30%), and an unknown anionic arsenic species (~4%). Most polychaetes accumulate arsenobetaine, except deposit feeders inhabiting estuarine mud habitats. Thus most polychaetes, which are prey for higher organisms, are a source of arsenobetaine in benthic food webs. Deposit feeders inhabiting estuarine muddy substrates contain appreciable quantities of inorganic arsenic and arsenoribosides that may be metabolized to different end products in higher organisms.

scholarly journals Groundwater Irrigation and Arsenic Speciation in Rice in Cambodia

2018 ◽  
Vol 8 (19) ◽  
Author(s):  
Tom Murphy ◽  
Kongkea Phan ◽  
Emmanuel Yumvihoze ◽  
Kim Irvine ◽  
Ken Wilson ◽  
...  
Keyword(s):  
Arsenic Speciation ◽  
Arsenic Concentration ◽  
Arsenic Exposure ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Dimethylarsinic Acid ◽  
Total Arsenic ◽  
Groundwater Irrigation ◽  
Financial Interests ◽  
Rice Consumption

Background. Arsenic bioaccumulation in rice is a global concern affecting food security and public health. Objective. The present study examined arsenic species in rice in Cambodia to characterize health risks with rice consumption and to clarify uncertainties with Codex guidelines. Methods. The present study collected 61 well water samples, 105 rice samples, 70 soil samples, and conducted interviews with 44 families in Preak Russey near the Bassac River and Kandal Province along the Mekong River in Cambodia. Analyses of metals, total arsenic and arsenic species were conducted in laboratories in Canada, Cambodia and Singapore. Results. Unlike in Bangladesh, rice with the highest total arsenic concentrations in Cambodia contains mostly organic arsenic, dimethylarsinic acid (DMA), which is unregulated and much less toxic than inorganic arsenic. The present study found that storing surface runoff in ditches prior to irrigation can significantly reduce the arsenic concentration in rice. It is possible to remove > 95% of arsenic from groundwater prior to irrigation with natural reactions. Conclusions. The provision of high quality drinking water in 2015 to Preak Russey removed about 95% of the dietary inorganic arsenic exposure. The extremes in arsenic toxicity that are still obvious in these farmers should become less common. Rice from the site with the highest documented levels of arsenic in soils and water in Cambodia passes current Codex guidelines for arsenic. Informed Consent. Obtained Competing Interests. The authors declare no competing financial interests.

Corrigendum to: Effect of humic acid, fulvic acid, pH, ionic strength and temperature on 63Ni(II) sorption to MnO2

2020 ◽  
Vol 108 (7) ◽  
pp. 591
Author(s):  
Guodong Sheng ◽  
Jun Hu ◽  
Han Jing ◽  
Shitong Yang ◽  
Xuemei Ren ◽  
...  
Keyword(s):  
Humic Acid ◽  
Ionic Strength ◽  
Fulvic Acid ◽  
Acid Ph

scholarly journals Determination of Organic Compounds, Fulvic Acid, Humic Acid, and Humin in Peat and Sapropel Alkaline Extracts

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2995
Author(s):  
Laurynas Jarukas ◽  
Liudas Ivanauskas ◽  
Giedre Kasparaviciene ◽  
Juste Baranauskaite ◽  
Mindaugas Marksa ◽  
...  
Keyword(s):  
Humic Acid ◽  
Fulvic Acid ◽  
Humic Substances ◽  
Organic Compounds ◽  
Chemical Constituents ◽  
Acid Amide ◽  
Extraction Methods ◽  
Ultrasound Extraction ◽  
Different Origins

Black, brown, and light peat and sapropel were analyzed as natural sources of organic and humic substances. These specific substances are applicable in industry, agriculture, the environment, and biomedicine with well-known and novel approaches. Analysis of the organic compounds fulvic acid, humic acid, and humin in different peat and sapropel extracts from Lithuania was performed in this study. The dominant organic compound was bis(tert-butyldimethylsilyl) carbonate, which varied from 6.90% to 25.68% in peat extracts. The highest mass fraction of malonic acid amide was in the sapropel extract; it varied from 12.44% to 26.84%. Significant amounts of acetohydroxamic, lactic, and glycolic acid derivatives were identified in peat and sapropel extracts. Comparing the two extraction methods, it was concluded that active maceration was more efficient than ultrasound extraction in yielding higher amounts of organic compounds. The highest amounts of fulvic acid (1%) and humic acid and humin (15.3%) were determined in pure brown peat samples. This research on humic substances is useful to characterize the peat of different origins, to develop possible aspects of standardization, and to describe potential of the chemical constituents.

Methylation of Arsenic by Freshwater Green Algae

1983 ◽  
Vol 40 (8) ◽  
pp. 1254-1257 ◽  
Author(s):  
M. D. Baker ◽  
P. T. S. Wong ◽  
Y. K. Chau ◽  
C. I. Mayfield ◽  
W. E. Inniss
Keyword(s):  
Green Algae ◽  
Lake Water ◽  
Sodium Arsenite ◽  
Basal Medium ◽  
Arsenic Species ◽  
Freshwater Ecosystems ◽  
Dimethylarsinic Acid ◽  
Additional Source ◽  
Arsenic Compounds ◽  
Methylarsonic Acid

Isolates from four genera of freshwater green algae were capable of methylating sodium arsenite in lake water and Bold's basal medium. Analysis of the liquid phase of the methylation flasks revealed the presence of methylarsonic acid, dimethylarsinic acid, and trimethylarsine oxide. Volatile arsine and methylarsines were not detected in the headspace gases presumably because of the inability of the algae to reduce completely the methylated–arsenic species. Although the algae varied with respect to their methylating abilities, the levels of methylated–arsenic compounds were always significantly higher when the algae were grown in lake water. This may have been due to the lower phosphate concentration in the lake water. We suggest that arsenic methylation by green algae constitutes an additional source for the formation and cycling of organo-arsenic compounds in freshwater ecosystems.

Arsenic Contamination and its Speciation in the Water System around the Abandoned Dongil Au-Ag Mine in Korea

2005 ◽  
Vol 277-279 ◽  
pp. 503-509 ◽  
Author(s):  
Ji Min Yi ◽  
Jin Soo Lee ◽  
Hyo Taek Chon
Keyword(s):  
Stream Water ◽  
Arsenic Concentration ◽  
Water System ◽  
Arsenic Species ◽  
High Concentration ◽  
Aqua Regia ◽  
Sequential Extraction Analysis ◽  
Fe Oxyhydroxides ◽  
High Level ◽  
Stream Waters

This study was made to investigate the extent and degree of As contamination in waters and sediments influenced by previous mining activity in the abandoned Dongil Au-Ag mine. Arsenic species was also identified in surface waters and groundwater. The chemical form of As in sediments was examined using sequential extraction analysis. The major contamination source of As in the mine area is suggested to be tailings with elevated levels of 8,718 As mg/kg. This was associated with the release of high level of As into the water system in the study area. The pH values of water samples ranged from 7.7 to 10.1, which was neutral to strong alkaline due to buffering effect by high concentration of Ca and Mg dissolved from carbonate mineral and weathering of concrete. Stream waters contained high level of As within the range of 40.5 to 150.4 ㎍/L and most waters exceeded the permissible level (50 ㎍/L) of As for stream water in Korea. The concentration ratios of As(Ⅲ) to As (total), however, extended in the range of 5.8 to 75% and increased at low pH condition in stream waters. Arsenic concentration in sediments digested by aqua regia (HNO3+HCl) ranged from 162 to 2,077 mg/kg. The highest concentration of As may be due to the direct inflow of tailings. The relatively high percentage (17.1~35.3%) of As coprecipitated with amorphous Fe oxyhydroxides indicates that more severe contamination of As can occur by re-extracting due to changes of chemical environment such as reducing condition.

Soil Augmentation by Humus: Replenishing lost soils and supplementing new ones

2021 ◽  
Author(s):  
Hemlata Bagla ◽  
Asma Khan
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Plant Growth ◽  
Humic Substances ◽  
Soil Degradation ◽  
Lunar Regolith ◽  
Radioactive Waste Disposal ◽  
Saline Stress ◽  
Plant Metabolites ◽  
Growth Phenomenon

<p>Earth’s regolith consists of a vital component that is lacking on other planets ­­– the pedosphere or soil body – that is rich in organic matter, soil fauna, minerals, water, gases, that together support life and is thus essential for plant growth. In stark contrast to our blue planet, Martian regolith is devoid of organic matter and contains crushed volcanic rocks, with high mineral content and toxic chemicals like perchlorates. Nevertheless, Martian and Lunar regolith simulants formulated by NASA, have been experimented for crop growth by addition of organic matter suitable to bind xenobiotics and provide ample nutrients, as an essential step towards expanding our horizon in the extensive field of soil sciences.</p><p>Soil is an ecosystem as a whole and acts as a modifier of planet Earth’s atmosphere. The organic matter present in it originates mainly from plant metabolites with the onset of senescence and humification. Humic substances thus formed in the pedosphere exhibit exceptional characteristics for soil conditioning. Besides providing nutrients and aeration to the soil, they interact and bind with toxic heavy metals, radionuclides, pesticides, industrial dyes, and other xenobiotics that may be present as pollutants in the ecosystem, thus acting as natural sieves. As top soils have maximum organic matter, essential for plant growth, phenomenon like soil erosion leave the soils devoid of humic substances. Another major reason for soil degradation is excessive salinity, leading to osmotic and ionic stress in plants, eventually reducing their growth. Addition of humic acid in soils provides protection against high saline stress and minimizes yield losses. In India, one of the leading agrarian countries, it is a common practice to enrich soils with manure, which is an inexpensive form of humus-boost for the crops. Such practices aid the cyclic flow of organic matter in the environment, against the background of widespread soil degradation.</p><p>Another global form of soil degradation is radioactive contamination of soils which occurs mainly due to nuclear accidents and improper practices of radioactive waste disposal. In order to explore such interactions with humic acid following Green technique, batch biosorption studies were performed over a range of parameters, with radionuclides Cs and Sr that are found in low level radioactive wastes. Biosorption percentages of 91±2% and 84±1% were obtained for Cs and Sr respectively. The technique is chemical-free and emphasizes the ‘nature for nature’ outlook of solving environmental problems. Humic acid and its various forms thus act as traps for radionuclides and work as excellent restorative soil stimulants that supplement depleted soils, boost plant growth, and play a vital role in sustaining life on Earth.</p>

Bioavailability of a nonylphenol isomer in dependence on the association to dissolved humic substances

2004 ◽  
Vol 50 (5) ◽  
pp. 277-283 ◽  
Author(s):  
R. Vinken ◽  
A. Höllrigl-Rosta ◽  
B. Schmidt ◽  
A. Schäffer ◽  
P.F.-X. Corvini
Keyword(s):  
Humic Acid ◽  
Carbon Source ◽  
Humic Substances ◽  
Organic Compounds ◽  
Sole Carbon Source ◽  
Equilibrium Dialysis ◽  
Fulvic Acids ◽  
Degrading Bacterium ◽  
Bacterium Strain ◽  
Dissolved Humic Substances

Humic substances are important environmental components since they represent a very large part of organic compounds on earth. According to many reports, dissolved humic substances are a determinant parameter for the bioavailability of xenobiotic compounds. For the present bioavailability studies, two kinds of dissolved humic substances, a commercially available humic acid and fulvic acids isolated from peat were used. As the relevant xenobiotic, a defined branched nonylphenol isomer, 4(3′,5′-dimethyl-3′-heptyl)-phenol (p353NP) was synthesised according to Friedel-Crafts alkylation. Equilibrium dialysis studies were implemented in order to investigate the association between 14C-labelled p353NP and dissolved humic substances. The biodegradability in the presence of dissolved humic substances was examined in experiments with the nonylphenol degrading bacterium strain Sphingomonas TTNP3 and with p353NP as sole carbon source. The results showed that p353NP-humic acid associates were formed in high amounts, whereas no adducts with fulvic acids occurred. In the degradation studies with Sphingomonas TTNP3, no effects of dissolved humic substances on the bioavailability of p353NP could be observed. It was assumed that the association between nonylphenol and humic acids occurs rapidly and is reversible. Thus, the formation of "labile" complexes did not influence biodegradation rates, which were quite low.

Sign in / Sign up

Export Citation Format

Share Document