Nobuhide Fujitake

l3C NMR spectra and elemental composition of fractions with different particle sizes from an andosol humic acid

Abstract Elemental composition and solution 13C NMR spectra for six humic acid fractions with different particle sizes (i.e. 3K, 10K, 30K, l00K, 300K, and 500K) which were prepared from a humic acid in an Umbric Andosol by successive gel permeation chromatography were determined. Elemental composition of the particle size fractions clearly differed from one another. Contents of nitrogen and hydrogen increased with the increase of the particle size. Small and middle particle size fractions (3K to l00K) showed low contents of hydrogen and nitrogen corresponding to those in typical Andosol humic acids, while the contents in the large fractions (300K and 500K) were distributed in the ranges of those in the other humic acids. As the particle size increased, the HIC ratio increased whereas the O/H decreased. In the HIC versus OIC diagram, the large particle size fractions (300K and 500K) were observed in the area around humic acids with a low humification degree. Variation of the chemical structural properties ...

Relation of chemical properties of soil humic acids to decolorization by white rot fungus–Coriolus consors

Abstract Humic acids (HAs) from 15 different soil samples were added to Czapek-Dox media inoculated with Coriolus consors IFO 9078. After 14 d incubation, decolorization of these culture media at 600 nm absorbance was measured. The aromaticity, the E 1% 600 value, the total acidity, and the elemental composition of the HAs were also determined, and the relationships between the decolorization and the chemical properties of HAs were examined. Percentage of decolorization of these culture media ranged from 8.8 to 39.5%. Andisol HAs showed a lower percentage of decolorization than the Inceptisol HAs. Percentage of decolorization showed highly negative correlations for the aromaticity, the E 1% 600 value, and the O / H ratio, and highly positive correlations for the hydrogen content and the H / C ratio. In particular, the highest correlation coefficient (r = −0.836**) was obtained between the aromati city and the decolorization. In addition, the HAs with a lower decolorization were arranged in the direction of dehydration on the H / C versus O / C diagram. These results showed that HAs with a higher aromaticity and a higher humification degree, showed a higher resistance to microbial decolorization by C. consors.

Properties of Soil Humic Substances in Fractions Obtained by Sequential Extraction with Pyrophosphate Solutions at Different pHs : II. Elemental Composition and UV-VIS Spectra of Humic Acids

Abstract The FT-IR and 1H NMR spectra of humic acids, which were obtained from four soils of different types (a Fibric Histosol, Dystric Cambisol, Umbric Andosol, and buried Umbric Andosol) by sequential extraction with pyrophosphate solutions at different pH values (i.e. at pH 3, 5, 7, 9, 11, and 13), were measured. The shape of the IR spectra for each humic acid depended on the differences in the soil origin rather than the pH values. The IR spectra of humic acids in the Histosol and Cambisol showed typical absorption associated with lignin. The humic acids in the Andosol and buried Andosol were characterized by the disappearance of the absorption assigned to aliphatic C-H and the prominence of the absorption attributed to aromatic C=C and COOH groups. The humic acids in the Histosol and Cambisol showed aliphatic properties compared with those in the Andosol and buried Andosol. As the pH values of tile extractant increased, the absorption strength of the bands attributed to aliphatic and amide groups in...

Comparability of composition of carbon functional groups in humic acids between inverse-gated decoupling and cross polarization/magic angle spinning 13C nuclear magnetic resonance techniques

To find a certain relation between the composition of carbon functional groups of humic acids derived from liquid state (13)C nuclear magnetic resonance (NMR) spectra acquired with inverse-gated decoupling (IGD), known as a quantitative pulse sequence, and that by solid-state (13)C NMR with cross polarization/magic angle spinning (CPMAS) techniques, fifteen soil humic acid samples with a wide range of aromaticity were analyzed. Relationships between the proportions of humic acid carbon as alkyl, O-alkyl, and aromatic carbon assessed by the two methods could be regressed to y=ax (r=0.932-0.956; P<0.005), respectively. The contents of alkyl, O-alkyl, and aromatic carbon assessed by CPMAS method were larger than those found by IGD method. However, the differences between the two methods were small and exclusive regression to y=x was also significant (r=0.775-0.941; P<0.005). Aromaticity calculated from (13)C CPMAS NMR data also did not differ significantly from those computed from (13)C NMR spectra with IGD. These observations indicated the comparability of the relative content of carbon functional groups in humic acids except for carboxyl and carbonyl carbon.

Molecular size fractionation of soil humic acids using preparative high performance size-exclusion chromatography

High performance size-exclusion chromatography (HPSEC) is useful for the molecular size separation of soil humic acids (HAs), but there is no method available for various HAs with different chemical properties. In this paper the authors propose a new preparative HPSEC method for various soil HAs. Three soil HAs with different chemical properties were fractionated by a Shodex OHpak SB-2004 HQ column with 10mM sodium phosphate buffer (pH 7.0)/acetonitrile (3:1, v/v) as an eluent. The HAs eluted within a reasonable column range time (12-25 min) without peak tailing. Preparative HPSEC chromatograms of these HAs indicated that non-size-exclusion effects were suppressed. The separated fractions were analyzed by HPSEC to determine their apparent molecular weights. These decreased sequentially from fraction 1 to fraction 10, suggesting that the HAs had been separated by their molecular size. The size-separated fractions of the soil HA were mixed to compare them with unfractionated HA. The analytical HPSEC chromatogram of the mixed HA was almost identical to that of the unfractionated HA. It appears that the HAs do not adsorb specifically to the column during preparative HPSEC. Our preparative HPSEC method allows for rapid and reproducible separation of various soil HAs by molecular size.

Role of natural organic matter on iodine and (239)(,240)Pu distribution and mobility in environmental samples from the northwestern Fukushima Prefecture, Japan.

In order to assess how environmental factors are affecting the distribution and migration of radioiodine and plutonium that were emitted from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, we quantified iodine and (239,240)Pu concentration changes in soil samples with different land uses (urban, paddy, deciduous forest and coniferous forest), as well as iodine speciation in surface water and rainwater. Sampling locations were 53-63 km northwest of the FDNPP within a 75-km radius, in close proximity of each other. A ranking of the land uses by their surface soil (<4 cm) stable (127)I concentrations was coniferous forest > deciduous forest > urban > paddy, and (239,240)Pu concentrations ranked as deciduous forest > coniferous forest > paddy ≥ urban. Both were quite distinct from that of (134)Cs and (137)Cs: urban > coniferous forest > deciduous forest > paddy, indicating differences in their sources, deposition phases, and biogeochemical behavior in these soil systems. Although stable (127)I might not have fully equilibrated with Fukushima-derived (129)I, it likely still works as a proxy for the long-term fate of (129)I. Surficial soil (127)I content was well correlated to soil organic matter (SOM) content, regardless of land use type, suggesting that SOM might be an important factor affecting iodine biogeochemistry. Other soil chemical properties, such as Eh and pH, had strong correlations to soil (127)I content, but only within a given land use (e.g., within urban soils). Organic carbon (OC) concentrations and Eh were positively, and pH was negatively correlated to (127)I concentrations in surface water and rain samples. It is also noticeable that (127)I in the wet deposition was concentrated in both the deciduous and coniferous forest throughfall and stemfall water, respectively, comparing to the bulk rainwater. Further, both forest throughfall and stemflow water consisted exclusively of organo-iodine, suggesting all inorganic iodine in the original bulk deposition (∼ 28.6% of total iodine) have been completely converted to organo-iodine. Fukushima-derived (239,240)Pu was detectable at a distance ∼ 61 km away, NW of FDNPP. However, it is confined to the litter layer, even three years after the FDNPP accident-derived emissions. Plutonium-239,240 activities were significantly correlated with soil OC and nitrogen contents, indicating Pu may be associated with nitrogen-containing SOM, similar to what has been observed at other locations in the United States. Together, these finding suggest that natural organic matter (NOM) plays a key role in affecting the fate and transport of I and Pu and may warrant greater consideration for predicting long-term stewardship of contaminated areas and evaluating various remediation options in Japan.

Surface-active properties of particle size fractions in two humic acids

Abstract The relationships between surface active properties and humic acid (HA) particle sizes were investigated. Two HAs from an Ando soil and a Brown forest soil were separated into 6 particle size fractions by gel permeation chromatography. Surface-active properties characterized by surface excess value (\gT mol cm-2), cross-sectional surface area per molecule (A nm2), critical micelle concentration (CMC g L-1), efficiency and effectiveness of water surface tension reduction were obtained by the measurement of the surface tension of HA solutions from different particle size fractions. For the HA from the Ando soil, except for the smallest particle size fraction, increasing particle size enhanced the efficiency of reduction of the water surface tension and decreased the CMC, while the effectiveness of reduction of the water surface tension was about the same. The surface activity of the HA from the Ando soil increased with increasing particle size. This phenomenon was similar to the surface activity of...

Characterization and grouping of aquatic fulvic acids isolated from clear-water rivers and lakes in Japan.

Characteristics of aquatic fulvic acids (FAs) from 10 clear waters in Japan (around the temperate zone) were revealed by several analytical techniques-high performance size exclusion chromatography (HPSEC), elemental analysis, liquid-state (13)C NMR spectroscopy, isotopic analyses (delta(13)C and delta(15)N), and compared with those of International Humic Substances Society (IHSS) standard samples including FAs from brown waters (Suwannee, Pony, and Nordic FAs). Generally clear-water FAs were different from brown-water FAs in chemical properties. Weight-average molecular weights (Mw) of the clear-water FAs were similar to each other, whereas their elemental compositions and carbon species distribution were different. The clear-water FAs all exhibited a high proportion of alkyl carbons, which may be attributed to microbial activity. delta(13)C and delta(15)N values of the FAs indicated that there would be a huge gap between origin and chemical structure of clear-water FA. Results of the chemical structural analyses described above were not always linked to those of the isotopic analyses (delta(13)C and delta(15)N). Multivariate statistical analysis, i.e. cluster and principal component analysis was applied to reveal differences or similarities in a more objective manner. The FAs were always classified into two clear-water groups and one brown-water group. Aryl-C and O-Alkyl-C contents were important for the grouping. We speculate that the grouping might depend on the differences of aquatic microbial activity caused by the differences of residence time of water.

14C ages and δ13C of sclerotium grains found in forest soils

Abstract 14C ages and δ13C were examined for sclerotium grains to elucidate the characteristics of these grains distributed in forest soils. The ages of the grains from surface A horizons and buried A horizons were ca 100–200 bp and ca 300–1,200 bp, respectively. In comparison with humic acid extracts, the 14C ages were in the increasing order: humic acid fraction < humic acid Pg fraction < sclerotium grains. The δ13C values for sclerotium grains in surface A horizons and buried A horizons were approximately −31‰ to −28‰, and these values were approximately 2–4‰ smaller than those of humic acids and soils. The C content of the grains had a tendency to decrease with increasing 14C ages, while the C content of humic acid was constant with age. The 14C ages of sclerotium grains indicate the individual age of grain formation, which are more likely to assign closer ages to the beginning of soil forming than the 14C ages of humic acid. The low δ13C values for sclerotium grains have presumably originated from characteristically biological organics, which may be protected from attack in soils because of their structure.

Distribution and development of sclerotium grains as influenced by aluminum status in volcanic ash soils

Abstract The distribution of sclerotium grains, which are considered to be the resting bodies formed by fungi species, was studied in 5 Andosol profiles in central Japan. Sclerotium grains were detected in the surface A and buried A horizons of nonallophanic (Alp / Alo > 0.5) soils but not in allophanic (Alp / Alo < 0.5) soils. The maximum density of the sclerotium grains in each profile was approximately 2.5 g kg−1. A highly positive relationship was observed between the mean weight of the sclerotium grains and the content of exchangeable aluminum (Al3+) in soils. Aluminum concentration inside of the sclerotium grains was confirmed by energy dispersive X-ray spectrometer (EDS) analysis. The results obtained suggest that the status of active Al in soils is an important factor for sclerotium development.