Association of organic matter, iron and inorganic phosphorus in lake waters

1980 ◽  
Vol 3 (6) ◽  
pp. 485-490 ◽  
Author(s):  
S.J. Eisenreich ◽  
D.E. Armstrong
2008 ◽  
Vol 8 (6) ◽  
pp. 681-690 ◽  
Author(s):  
H. M. Szabo ◽  
I. Lindfors ◽  
T. Tuhkanen

In this study Natural organic matter (NOM) characteristics and variations of catchment samples (brooks and collector lakes) from Western Finland, and drinking water produced from the same catchment were examined. Seasonal and spatial NOM variations were followed by means of DOC and HPLC-SEC with UV and fluorescence detection. NOM decreased from drains to lakes by 35 to 75% and from drains to drinking water by 73 to 94%. Drains had a higher NOM content in summer and a lower NOM content in winter and spring. Lakes showed inverse patterns and had a higher NOM content in winter and spring and a lower NOM content in summer. HPLC-SEC separated 8 molecular weight fractions. In drains the HMW fractions represented up to 80% of the NOM, in lake waters HMW fractions accounted for 50 to 70% of the NOM. In drinking water IMW fractions dominated. Increased NOM in raw water during winter was associated with increased IMW fractions and the appearance of HMW fractions in drinking water, DOC increasing from 1.4 mg C/L in summer to 5.8 mg C/L in winter. SPH-Tryptophan correlated with the dissolved organic nitrogen and DOC of the samples. The drain affected by agriculture generally presented higher SPH-Tryptophan values than the unaffected drain.


2021 ◽  
pp. geochem2021-009
Author(s):  
Lamiae EL ALAOUI ◽  
Abdelilah Dekayir ◽  
Mohammed Rouai ◽  
EL Mehdi Benyassine

In the Zeida abandoned mine, pit lake waters exhibit alkaline pH and high conductivity. The concentrations of the total dissolved lead and zinc are very low due to their adsorption on clay minerals and iron oxyhydroxides. Conversely, arsenic concentrations in two lakes (ZL1 and ZA) exceeded WHO water quality guidelines. The As content is relatively high in ZL1 lake and exists mainly as As(V). In ZA lake, As(III) occurs in low concentration compared to the total dissolved arsenic, while dimethylarsenic acid [H2AsO2(CH3)2, DMA) prevails. This means that arsenic was methylated by organic matter produced by microorganisms such as chlorella. The sequential extraction of floor sediments in two lakes shows that the bioavailable arsenic contents change between the two lakes. In ZA lake, the sediments show high concentrations of lead and arsenic compared to ZL1 sediment since it is surrounded by mining waste tailings, which are rich in such chemical elements. An arsenic leaching test of ZA sediment shows that bioavailable arsenic is distributed in equal proportion between clay/carbonates, sulfide-organic matter, and iron oxides (HFO) phases, while in ZL1, most of the arsenic is linked to hydrous iron oxides (HFO).Thematic collection: This article is part of the Hydrochemistry related to exploration and environmental issues collection available at: https://www.lyellcollection.org/cc/hydrochemistry-related-to-exploration-and-environmental-issuesSupplementary material:https://doi.org/10.6084/m9.figshare.c.5545316


1969 ◽  
Vol 49 (3) ◽  
pp. 365-373 ◽  
Author(s):  
M. Lévesque

Fulvic acid–metal–phosphate complexes prepared in the laboratory and corresponding complexes extracted (0.1 N NaOH and chelating resin) from a soil were characterized by means of electrophoresis, Sephadex gel filtration, and methods for differentiation of organic and inorganic phosphorus. The findings can be summarized as follows:(1) The prepared material in aqueous solution (after purification by dialysis) comprised three different entities: a fulvic acid–metal–phosphate complex, a fulvic acid–metal complex, and unbonded inorganic phosphate. These entities were reaction products obtained during the formation of fulvic acid–metal–phosphate complexes.(2) Upon hydrolysis in mild alkaline media, the metal–phosphate bonds of the fulvic acid–metal–phosphate complexes were broken; the fulvic acid–metal complexes, freed from the phosphate, remained intact.(3) While metal ions were necessary for bridging phosphorus and fulvic acid, phosphorus in turn may have bridged the fulvic acid–metal units.(4) Significant amounts of complexed inorganic phosphorus were found intermixed with organic phosphorus compounds in soil extracts; this suggested the existence of organic matter metal–phosphate complexes in soil.


2021 ◽  
Vol 18 (9) ◽  
pp. 2981-3004
Author(s):  
Astrid Hylén ◽  
Sebastiaan J. van de Velde ◽  
Mikhail Kononets ◽  
Mingyue Luo ◽  
Elin Almroth-Rosell ◽  
...  

Abstract. Phosphorus fertilisation (eutrophication) is expanding oxygen depletion in coastal systems worldwide. Under low-oxygen bottom water conditions, phosphorus release from the sediment is elevated, which further stimulates primary production. It is commonly assumed that re-oxygenation could break this “vicious cycle” by increasing the sedimentary phosphorus retention. Recently, a deep-water inflow into the Baltic Sea created a natural in situ experiment that allowed us to investigate if temporary re-oxygenation stimulates sedimentary retention of dissolved inorganic phosphorus (DIP). Surprisingly, during this 3-year study, we observed a transient but considerable increase, rather than a decrease, in the sediment efflux of DIP and other dissolved biogenic compounds. This suggested that the oxygenated inflow elevated the organic matter degradation in the sediment, likely due to an increase in organic matter supply to the deeper basins, potentially combined with a transient stimulation of the mineralisation efficiency. As a result, the net sedimentary DIP release per m2 was 56 %–112 % higher over the years following the re-oxygenation than before. In contrast to previous assumptions, our results show that inflows of oxygenated water to anoxic bottom waters can increase the sedimentary phosphorus release.


2015 ◽  
Vol 12 (2) ◽  
pp. 1975-2019
Author(s):  
R. M. Manasypov ◽  
S. N. Vorobyev ◽  
S. V. Loiko ◽  
I. V. Kritzkov ◽  
L. S. Shirokova ◽  
...  

Abstract. Western Siberia's thermokarst (thaw) lakes extend over a territory spanning over a million km2; they are highly dynamic hydrochemical systems that receive chemical elements from the atmosphere and surrounding peat soil and vegetation, and exchange greenhouse gases with the atmosphere, delivering dissolved carbon and metals to adjacent hydrological systems. This work describes the chemical composition of ~ 130 thermokarst lakes of the size range from a few m2 to several km2, located in the discontinuous permafrost zone. Lakes were sampled during spring floods, just after the ice break (early June), the end of summer (August), the beginning of ice formation (October) and during the full freezing season in winter (February). Dissolved organic carbon (DOC) and the major and trace elements do not appreciably change their concentration with the lake size increase above 1000 m2 during all seasons. On the annual scale, the majority of dissolved elements including organic carbon increase their concentration from 30 to 500%, with a statistically significant (p < 0.05) trend from spring to winter. The maximal increase in trace element (TE) concentration occurred between spring and summer and autumn and winter. The ice formation in October included several stages: first, surface layer freezing followed by crack (fissure) formation with unfrozen water from the deeper layers spreading over the ice surface. This water was subsequently frozen and formed layered ice rich in organic matter. As a result, the DOC and metal concentrations were the highest at the beginning of the ice column and decreased from the surface to the depth. A number of elements demonstrated the accumulation, by more than a factor of 2, in the surface (0–20 cm) of the ice column relative to the rest of the ice core: Mn, Fe, Ni, Cu, Zn, As, Ba and Pb. The main consequences of discovered freeze-driven solute concentrations in thermokarst lake waters are enhanced colloidal coagulation and the removal of dissolved organic matter and associated insoluble metals from the water column to the sediments. The measured distribution coefficient of TE between amorphous organo-ferric coagulates and lake water (< 0.45 μm) were similar to those reported earlier for Fe-rich colloids and low molecular weight (< 1 kDa) fractions of thermokarst lake waters, suggesting massive co-precipitation of TE with amorphous Fe oxy(hydr)oxide stabilized by organic matter. Although the concentration of most elements is lowest in spring, this period of maximal water coverage of land creates a significant reservoir of DOC and soluble metals in the water column that can be easily mobilized to the hydrological network. The highest DOC concentration observed in the smallest (< 100 m2) water bodies in spring suggests their strongly heterotrophic status and, therefore, elevated CO2 flux from the lake surface to the atmosphere.


2021 ◽  
Author(s):  
Marina Dinu

&lt;p&gt;The reactions of toxicants with organic substances of a humic nature are complex and depend on many geochemical factors. Differences in the mechanisms of the selected toxicants binding with organic natural substances of various natural waters - atmospheric precipitation, lake waters (acidic and alkaline), lysimetric waters are especially interesting. Due to significant concentration differences, features of functional groups and size distribution of components, the inactivation features of humic substances are selective and highly variable. We studied the waters of an acid lake near the city of Valday (Valday National Park, conditionally a background lake) and alkaline lake Valday (city of Valday, local technogenic influence). Near each lake there was a sediment collector (a container for collecting atmospheric precipitation) and a lysimeter (a container under the soil for collecting soil moisture) under the humus horizon (about 20 cm). Particular attention was paid to soil (lysimetric) waters with varying degrees of anthropogenic impact. We considered the behavior of a large group of heavy metals, as well as benzopyrene. To assess the composition and qualitative features of organic substances, gas chromatography-mass spectrometric methods of analysis were used. Chromatographic methods were used to assess the molecular weight distribution of the components. Possible reaction mechanisms were studied by IR spectral methods. Evaluation of the reactivity of organic substances was carried out by the methods of dynamic light scattering (zeta potential, MM, size) using the &quot;Zeta-sizer nano&quot;. In addition to humic substances in the waters, the contents of autochthonous organic matter were estimated, especially in an alkaline lake, which in some periods prevailed over humic ones. In addition to humic substances in the waters, the contents of autochthonous organic matter were estimated, especially in an alkaline lake, which in some periods prevailed over humic ones. For separation, exchange technique and fluorometric evaluations were used. We conducted research in the period 2015-2020, sampling was carried out in spring, summer, autumn. Thus, we studied the circulation (in miniature) of changes in the protective properties of humic substances, depending on a large number of factors.&lt;/p&gt;


2007 ◽  
Vol 38 (3) ◽  
pp. 265-285 ◽  
Author(s):  
Birgot Paavel ◽  
Helgi Arst ◽  
Antti Herlevi

The study focuses on the analysis of inherent optical properties of lake waters characterized by consisting of several optically active substances (OAS) (phytoplankton, suspended particles and dissolved organic matter). The results obtained can be useful for deriving the algorithms of optical remote sensing models which need the spectral data on inherent optical properties of the aquatic environment. The spectral absorption and attenuation coefficients were measured in situ using the instrument ac-9 for eight wavelengths in the range of 400–700 nm. The investigation sites were five Finnish and six Estonian lakes. The concentrations of chlorophyll a and total suspended particulate matter, as well as the absorption coefficient of coloured dissolved organic matter (at 380 nm) were determined in a laboratory from water samples taken concurrently with ac-9 measurements. There are three main objectives: (1) to calculate the values of absorption and specific absorption coefficients of tripton on the basis of ac-9 and laboratory data; (2) to estimate the contribution of pure water, chlorophyll a, dissolved organic matter and tripton to the total absorption and attenuation coefficients (results for ac-9 wavelengths and also for the PAR region, 400–700 nm); and (3) to determine the slope (and its variability) of the scattering coefficient spectrum for each measurement series and to estimate the reasons of this variability. At the wavelength of 532 nm the values of the specific absorption coefficient of tripton varied between 0.013 and 0.098 L mg−1 m−1, while the slope of its spectrum ranged from 0.0060 to 0.0109 nm−1. The contributions of different components of the aquatic medium to the total absorption/attenuation coefficients varied noticeably from lake to lake. The slope of the scattering coefficient spectrum was in the range of 0.32–2.5, the multiple regression between the slope and three main optically active substances jointly gave the determination coefficient R2(adjusted)=0.655.


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