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

2012 ◽  
Vol 9 (4) ◽  
pp. 356 ◽  
Author(s):  
Kristin K. Mueller ◽  
Stephen Lofts ◽  
Claude Fortin ◽  
Peter G. C. Campbell
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Trace Metal ◽  
Metal Binding ◽  
Natural Waters ◽  
Metal Speciation ◽  
Chemical Species ◽  
Metal Species ◽  
Fluorescence Measurements ◽  
Shield Lakes

Environmental contextTo 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. AbstractTo 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 Cd2+, Cu2+, Ni2+ and Zn2+ 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 Cd2+ and Zn2+ fall within the range of values predicted by WHAM; the measured proportion of Cu2+ falls within this range for only half of the lakes sampled, whereas for Ni, WHAM systematically overestimated the proportion of Ni2+. 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.

Complexation of Dissolved Organic Matter with Trace Metal Ions in Natural Waters

2012 ◽  
pp. 769-849 ◽  
Author(s):  
Khan M. G. Mostofa ◽  
Cong-qiang Liu ◽  
Xinbin Feng ◽  
Takahito Yoshioka ◽  
Davide Vione ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Trace Metal ◽  
Metal Ions ◽  
Natural Waters ◽  
Trace Metal Ions

scholarly journals Impact of forest harvesting on water quality and fluorescence characteristics of dissolved organic matter in eastern Canadian Boreal Shield lakes in summer

2015 ◽  
Vol 12 (23) ◽  
pp. 6999-7011 ◽  
Author(s):  
P. Glaz ◽  
J.-P. Gagné ◽  
P. Archambault ◽  
P. Sirois ◽  
C. Nozais
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Forest Harvesting ◽  
Spectroscopic Techniques ◽  
Clear Cutting ◽  
Fluorescence Measurements ◽  
Fluorescence Characteristics ◽  
Boreal Shield ◽  
Shield Lakes

Abstract. Forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. Water quality and fluorescence characteristics of dissolved organic matter (DOM) were measured over a 3-year period in eight eastern Boreal Shield lakes: four lakes were studied before, 1 and 2 years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. ANOVAs showed a significant increase in total phosphorus (TP) in perturbed lakes when the three sampling dates were considered and in DOC concentrations when considering 1 year before and 1 year after the perturbation only. At 1 year post-clear cutting DOC concentrations were about 15 % greater in the perturbed lakes at ~ 15 mgC L−1 compared to 12.5 mgC L−1 in the unperturbed lakes. In contrast, absorbance and fluorescence measurements showed that all metrics remained within narrow ranges compared to the range observed in natural waters, indicating that forest harvesting did not affect the nature of DOM characterized with spectroscopic techniques. These results confirm an impact of forestry activities 1 year after the perturbation. However, this effect seems to be mitigated 2 years after, indicating that the system shows high resilience and may be able to return to its original condition in terms of water quality parameters assessed in this study.

scholarly journals The optical characteristics and sources of chromophoric dissolved organic matter (CDOM) in seasonal snow of northwestern China

2018 ◽  
Author(s):  
Yue Zhou ◽  
Hui Wen ◽  
Jun Liu ◽  
Wei Pu ◽  
Qingcai Chen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Chemical Species ◽  
Anthropogenic Pollution ◽  
Northwestern China ◽  
Chromophoric Dissolved Organic Matter ◽  
Seasonal Snow ◽  
The North ◽  
Fluorescence Measurements ◽  
Potential Sources

Abstract. Chromophoric dissolved organic matter (CDOM) plays an important role in the global carbon cycle and energy budget. A field campaign was conducted across northwestern China from January to February 2012, and surface seasonal snow samples were collected at 39 sites in Xinjiang and Qinghai provinces. Light-absorption measurements, fluorescence measurements and chemical analysis were conducted to investigate the optical properties and potential sources of CDOM in seasonal snow. The abundance of CDOM (the absorption coefficient at 280 nm, a280) and the spectral slope from 275 to 295 nm (S275–295) ranged from 0.15–10.57 m−1 and 0.0129–0.0389 nm−1, respectively. The highest average a280 (2.30±0.52 m−1) and lowest average S275–295 (0.0188±0.0015 nm−1) in Qinghai indicated that the snow CDOM in this region had strongly terrestrial characteristic. Relatively low regional average a280 values were found in sites located to the north of the Tianshan Mountains and northwestern Xinjiang along the border of China (0.93±0.68 m−1 and 0.80±0.62 m−1, respectively). Parallel factor analysis (PARAFAC) identified three types of chromophores that were attributed to two humic-like substances (HULIS, C1 and C2) and one protein-like material (C3). C1 was mainly from soil HULIS, while the potential sources of C2 were complex and included soil, microbial activities, anthropogenic pollution and biomass burning. The good relationship between a280 and the intensity of C1 (R2 = 0.938, p<0.001) indicated that the CDOM abundance in the surface snow across northwestern China was mainly controlled by terrestrial sources. In addition, the regional variations of sources for CDOM in snow were further assessed by the analysis of chemical species (e.g., soluble ions) and air mass backward trajectories combined with satellite fire locations.

Toxicity of Heavy Metals to the Marine Diatom Ditylum Brightwellii (West) Grunow: Correlation between Toxicity and Metal Speciation

1980 ◽  
Vol 60 (1) ◽  
pp. 227-242 ◽  
Author(s):  
G. S. Canterford ◽  
D. R. Canterford
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Natural Waters ◽  
Chelating Agents ◽  
Sea Water ◽  
Metal Speciation ◽  
Marine Diatom ◽  
Dissolved Organic Compounds ◽  
Inorganic Ligands

The possibility of dissolved organic compounds acting as complexing or chelating agents in natural waters has received considerable attention in the last two to three decades. Stumm & Morgan (1970) have expressed doubts about the existence of humicmetal ion complexes in natural waters. Strickland (1972) has also stated that although the addition of chelating agents to sea water often improved the growth of phytoplankton, there was little evidence that the function of dissolved organic matter in oceans and lakes was to complex metals so as to increase or decrease their availability to phytoplankton. Strickland argued that even if all dissolved organic carbon were present as a compound of strong complexing ability it would not be able to compete for most metals with inorganic ligands such as chloride, sulphate and hydroxide. However, there is an increasing amount of data indicating that metals in natural waters may exist in chelated forms with dissolved organic matter (see, for example, Davey, Morgan & Erickson, 1973; Chau & Lum-Shue-Chan, 1974).

scholarly journals Impact of forest harvesting on water quality and fluorescence characteristics of dissolved organic matter in Eastern Canadian Boreal Shield lakes

2015 ◽  
Vol 12 (12) ◽  
pp. 9307-9339 ◽  
Author(s):  
P. Glaz ◽  
J.-P. Gagné ◽  
P. Archambault ◽  
P. Sirois ◽  
C. Nozais
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Forest Harvesting ◽  
Clear Cutting ◽  
Fluorescence Measurements ◽  
Fluorescence Characteristics ◽  
Boreal Shield ◽  
One Year ◽  
Shield Lakes

Abstract. Forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. Water quality and fluorescence characteristics of dissolved organic matter (DOM) were measured over a three-year period in eight Eastern Boreal Shield lakes: four lakes were studied before, one and two years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. ANOVAs showed a significant increase in total phosphorus (TP) in perturbed lakes when the three sampling dates were considered and in DOC concentrations when considering one year before and one year after the perturbation only. At one year post-clear cutting DOC concentrations were about 15 % greater in the perturbed lakes at ~15 mg C L−1 compared to 12.5 mg C L−1 in the unperturbed lakes. In contrast, absorbance and fluorescence measurements showed that all metrics remained within narrow ranges compared to the range observed in natural waters, indicating that forest harvesting did not affect the nature of DOM characterised with spectroscopic techniques. Multivariate statistical analysis showed lakes to be significantly different one year after the perturbation. These results confirm an impact of forestry activities one year after the perturbation. However, this effect seems to be mitigated two years after, indicating that the system shows high resilience and may be able to return to its original condition.

scholarly journals Photochemical effects on the interaction of enzymes and dissolved organic matter in natural waters

2003 ◽  
Vol 48 (5) ◽  
pp. 1818-1824 ◽  
Author(s):  
Norman M. Scully ◽  
Lars J. Tranvik ◽  
William J. Cooper
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Natural Waters

Effect of dissolved organic matter composition on metal speciation in soil solutions

2015 ◽  
Vol 398 ◽  
pp. 61-69 ◽  
Author(s):  
Zong-Ling Ren ◽  
Marie Tella ◽  
Matthieu N. Bravin ◽  
Rob N.J. Comans ◽  
Jun Dai ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Metal Speciation ◽  
Organic Matter Composition ◽  
Soil Solutions

scholarly journals Optical Properties of Dissolved Organic Matter in Finnish and Estonian Lakes

2003 ◽  
Vol 34 (4) ◽  
pp. 361-386 ◽  
Author(s):  
L. Sipelgas ◽  
H. Arst ◽  
K. Kallio ◽  
A. Erm ◽  
P. Oja ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Natural Waters ◽  
Mean Value ◽  
Published Data ◽  
Optical Parameters ◽  
Exponential Approximation ◽  
Absorption Coefficients ◽  
Specific Absorption ◽  
The Mean

The main objective of the present study is to test various methods for describing the absorption spectra of coloured dissolved organic matter (CDOM) and to determine the numerical values of some optical parameters of CDOM in lakes with diverse water quality. First, the parameters of an exponential model in different spectral intervals were determined. In addition, the suitability of some other models for the approximation of CDOM spectra was estimated. Specific absorption coefficients of CDOM were calculated from the absorption coefficients and dissolved organic carbon (DOC) concentrations. The experimental initial data were differences between spectral attenuation coefficients of filtered and distilled water. Two datasets were used: 1) for 13 Estonian and 7 Finnish lakes (altogether 404 spectra between 350 and 700 nm) measured by the Estonian Marine Institute (EMI); 2) for 10 Finnish lakes (73 spectra) measured by the Finnish Environment Institute (FEI). The spectra of CDOM absorption coefficients (aCDOM) were calculated from experimental data taking into account the correction due to scattering properties of colloids in the filtered water. The total content of CDOM in natural waters of Estonian and Finnish lakes was expressed by means of aCDOM at the wavelength of 380 nm. It varied significantly, from 0.71 to 19.5 m−1, the mean value (of all the investigated lakes) being around 6.6 m−1. Slopes of the exponential approximation varied widely, from 0.006 to 0.03 nm−1. Averaged over all lakes values of slope for the interval 380-500 nm obtained from the EMI dataset are close to those obtained from the FEI dataset: from 0.014 nm−1 (without correction) to 0.016-0.017 nm-1 (with different types of correction). These results are in good correspondence with most published data. Attempts to describe the spectra in the region of 350-700 nm by means of hyperexponential functions (∽ exp(-αλη)) show that: (1) η &lt; 1 (in the case of traditional exponential approximation η = 1); (2) a promising idea is to seek the best fit only for wavelengths λ &gt; λ1, where λ1 will be chosen taking into account the real shape of aCDOM spectra. The mean value of the specific absorption coefficient (a*CDOM) at the wavelength 380 nm obtained in this study (0.44 L mg−1 m−1) is close to the values published in the literature, if we assume that a*CDOM (380) is calculated using the data of dissolved organic matter (DOM). The optically non-active fraction of DOM in our study was high and therefore a*CDOM (380) was considerably higher (1.01 L mg−1 m−1) than a*CDOM (380). The results of the present work could be used in the modeling of underwater light field as well as in the interpretation of radiation measurements and optical remote sensing results.

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