On the composition and properties of humic substances isolated from deep groundwater and surface waters

Pettersson, Catharina; Ephraim, James H.; Allard, Bert

doi:10.1016/0146-6380(94)90096-5

Cited by 86 publications

(57 citation statements)

References 15 publications

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“…This is in agreement with the stronger refractory character of NRFA and NRHA during volatilisation compared to ISOM (Nyeki et al, 2003). Distinctly larger molar masses (number averaged) of 2180 kg/kmol and 4410 kg/kmol for NRFA and NRHA, respectively, have previously been reported by Pettersson et al (1994). However, they used size exclusion chromatography which has been reported to give higher average molar mass estimates for humic substances than other techniques (Leenheer et al, 2001).…”

Section: ≥18 M)mentioning

confidence: 86%

Hygroscopic properties of water-soluble matter and humic-like organics in atmospheric fine aerosol

et al. 2004

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Abstract. Ambient continental-rural fine aerosol (K-puszta, Hungary, PM 1.5 ) was sampled on quartz fibre filters in winter and summer 2001. Water-soluble matter (WSM) was extracted in MilliQ-water, and, in a second step, solid phase extraction was used to isolate the less hydrophilic fraction (ISOM) of the water-soluble organic matter (WSOM) from remaining inorganic salts and "most" hydrophilic organic matter (MHOM). This approach allowed ISOM, which constitutes the major fraction of WSOM, to be isolated from ambient aerosols and investigated in pure form. Hygroscopic properties of both WSM and ISOM extracts as well as of aquatic reference fulvic and humic acids were investigated using a Hygroscopicity Tandem Differential Mobility Analyser (H-TDMA). ISOM deliquesced between 30% and 60% relative humidity (RH), and hygroscopic growth factors at 90% RH ranged from 1.08 to 1.17. The hygroscopicity of ISOM is comparable to secondary organic aerosols obtained in smog chamber experiments, but lower than the hygroscopicity of highly soluble organic acids. The hygroscopic behaviour of investigated fulvic and humic acids had similarities to ISOM, but hygroscopic growth factors were slightly smaller and deliquescence was observed at higher RH (75-85% and 85-95% RH for fulvic acid and humic acid, respectively). These differences probably originate from larger average molecular mass and lower solubility of fulvic and humic acids.Inorganic composition data, measured ISOM hygroscopicity, and a presumed value for the hygroscopicity of the small remaining MHOM fraction were used to predict hygroscopic growth of WSM extracts. Good agreement between model prediction and measured water uptake was observed with differences (by volume) ranging from +1% to −18%. While deliquescence properties of WSM extracts were mainly determined by the inorganic salts (42-53 wt % Correspondence to: E. Weingartner (ernest.weingartner@psi.ch) of WSM), the WSOM accounted for a significant fraction of particulate water. At 90% RH, according to model predictions and measurements, about 80-62% of particulate water in the samples are associated with inorganic salts and about 20-38% with WSOM. The relative contributions of both distinguished WSOM fractions, ISOM and MHOM, remains uncertain since MHOM was not available in isolated form, but the results suggest that the less abundant MHOM is also important due to its presumably larger hygroscopicity.

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Section: ≥18 M)mentioning

confidence: 86%

Hygroscopic properties of water-soluble matter and humic-like organics in atmospheric fine aerosol

et al. 2004

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“…First, the 1,000-Da retentates are very brown, implying the presence of humic material that typically has molecular weights between 2,000-10,000 (MacCarthy and Suffet 1989; Higgo et al 1992;Pettersson et al 1994) and would therefore be retained by the 1,000-Da membrane. Second, organic carbon occurs in millimolar concentrations in 0.45-m filtrates, whereas Si, Al, and Fe, other phases that may form colloidal particles, occur in micromolar amounts.…”

Section: Resultsmentioning

confidence: 99%

Role of colloids and fine particles in the transport of metals in rivers draining carbonate and silicate terrains

Hill

Aplin

2001

Limnology & Oceanography

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We have used cross flow filtration (CFF) to determine the pools of fine particulate (0.1-0.45 m), colloidal (1,000 Dalton to 0.1 m), and dissolved (Ͻ1,000 Dalton) metals in seven rivers that are all relatively rich in organic matter but have differing pH, alkalinity, and ionic strength. The metal content of Ͻ0.45-m filtered river water primarily reflects a mixing of two metal pools with differing elemental compositions: a truly dissolved pool and a colloidal pool. Fine particulate metals contribute Ͻ10% of the total metal load of Ͻ0.45-m filtered water. Colloidal metals generally comprise at least the following percentages of the metal load of Ͻ0.45-m filtered water: Ͼ50% of Fe, Al, and trace metals; 30% Mn, 25% Ca and Mg; 15% Na and K; and a few percent Si. We believe that these figures are minima because recovery experiments with the CFF apparatus suggest that whilst recoveries of pure metal salt solutions are close to 100%, only 70% of particle-reactive metals are recovered from metal salt solutions spiked with humic acid. We propose that the metal composition of riverine colloids is primarily controlled by element mobility during weathering. In organic-rich soils with low acid-neutralizing capacity, low pH solutions drive the dissolution of aluminosilicates and oxides. Uptake of Al, Fe, and trace metals onto colloidal organic matter helps to maintain low activities of dissolved metals and enhances mineral dissolution. Colloids derived from these soils are thus enriched in Al, Fe, Mn, and trace metals, resulting in high concentrations of these elements in Ͻ0.45-m filtered water. In carbonate-rich soils, rapid neutralization of rainwater by carbonate minerals restricts the mobilization of aluminosilicates and oxides. Compared to colloids from rivers draining silicate terrains, colloids in carbonate-rich systems have higher total loadings of metals, are enriched in alkali and alkaline earth metals, but are depleted in Al, Fe, and trace metals.Quantifying weathering processes and the subsequent transport of elements to the ocean is a fundamental aim of geochemistry. Although the abundance of dissolved elements has been commonly and pragmatically quantified by filtering water at 0.45 m, it is well known that sub-0.1-m colloidal phases, such as organic matter and oxides, interact strongly with dissolved metals (for reviews see Buffle 1988;Stumm 1992Stumm , 1993Gustafsson and Gschwend 1997). Several previous studies suggest that colloids can be important metal carriers in freshwater (e.g., Giesy and Briese 1977;Reuter and Perdue 1977;Hoffmann et al. 1981;Salbu et al. 1985;Tanizaki et al. 1992;Dai and Martin 1995;Ross and Sherrell 1999), and it is likely that the loss of metals from estuarine water is related to the coagulation of colloids (Sholkovitz 1976;Boyle et al. 1977).This paper reports the results of a study aimed at determining the importance of colloids as metal carriers in a series of rivers of widely varying pH and ionic strength. Cross flow filtration (CFF) is developed as a method of fraction-1...

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“…They are produced in sediments in the decay process of plant and animal tissues as an intermediate step in the eogenetic pathway from higher plant material to kerogen and eventually coal (16,20). Humic substances are divided into humic acids and fulvic acids based on differences in elemental characteristics and chemical properties (16)(17)(18)(19)30). Recently, humic substances from the Skagen aquifer were characterized in detail (18,30).…”

Section: Discussionmentioning

confidence: 99%

Iodine in drinking water in Denmark is bound in humic substances

Andersen

Petersen

Laurberg

2002

European Journal of Endocrinology

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Objective: The iodine intake level is important for the occurrence of thyroid disorders in a population. We have previously found that iodine in drinking water is related to iodine excretion but whether iodine is present as iodide or bound in other molecules remains unknown. Design: We measured iodine in drinking water from 22 locations in Denmark. Six locations were selected by iodine content for further tap water analysis (Skagen 140 mg/l, Samsoe 56 mg/l, Nykoebing S. 50 mg/l, Nakskov 40 mg/l, Ringsted 38 mg/l, Copenhagen 19 mg/l). Methods: HPLC size exclusion before (Skagen) and after (all sites) freeze drying and measurement of absorbance (280 nm) and iodine in fractions, and fluorescence spectroscopy of bulk organic matter in Skagen drinking water. Results: Iodine content was unaltered after 3 years ðP ¼ 0:2Þ: All samples contained organic molecules with characteristics similar to humic substances. Most iodine eluted with humic substances (Skagen 99%, Ringsted 98%, Nykoebing S. 90%, Copenhagen 90%, Samsoe 75%, Nakskov 40%). Changing pH and ionic strength and preincubation with iodide indicated that iodine was bound in humic substances. Humic substances may affect thyroid function but differ with geology. Geological and geochemical data agree with tap water humic substances having been released from marine deposits. Iodine is abundant in the marine environment and marine deposits are particularly rich in iodine. Correlation analysis ðr ¼ 0:85; P ¼ 0:03Þ conform to iodine in drinking water, suggesting marine humic substances at the source rock. Conclusion: Iodine in Danish drinking water varied considerably. In drinking water with a high iodine content, the iodine mainly eluted with humic substances derived from marine source rock. We hypothesize that iodine in drinking water in general suggests coexisting humic substances of marine origin.

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On the composition and properties of humic substances isolated from deep groundwater and surface waters

Cited by 86 publications

References 15 publications

Hygroscopic properties of water-soluble matter and humic-like organics in atmospheric fine aerosol

Hygroscopic properties of water-soluble matter and humic-like organics in atmospheric fine aerosol

Role of colloids and fine particles in the transport of metals in rivers draining carbonate and silicate terrains

Iodine in drinking water in Denmark is bound in humic substances

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