Fluorescence characterization of the natural organic matter in deep ground waters from the Canadian Shield, Ontario, Canada

Sharp-King, Karen; Siemann, Stefan; Smith, D. Scott

doi:10.1007/s10967-010-0735-x

Cited by 7 publications

(2 citation statements)

References 28 publications

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“…RGW fluorescence was essentially similar to that of our laboratory water used as a blank, water that has been extensively purified to remove DOM. A PARAFAC fluorescence model of deep groundwater (>600 m) taken from a borehole in the Canadian Shield (Ontario, Canada) showed substantially reduced intensity compared to shallow groundwater, especially in humic‐like components matching C1 and C4 from the La Selva model in this study (Caron et al, ). While the residence time in that study was not reported, the presence of fluorescent DOM, albeit at low intensities, suggests that RGW feeding streams at La Selva were far more altered than bedrock groundwater analyzed by Caron et al ().…”

Section: Discussionmentioning

confidence: 49%

“…A PARAFAC fluorescence model of deep groundwater (>600 m) taken from a borehole in the Canadian Shield (Ontario, Canada) showed substantially reduced intensity compared to shallow groundwater, especially in humic‐like components matching C1 and C4 from the La Selva model in this study (Caron et al, ). While the residence time in that study was not reported, the presence of fluorescent DOM, albeit at low intensities, suggests that RGW feeding streams at La Selva were far more altered than bedrock groundwater analyzed by Caron et al (). Altogether, these results strongly suggest that RGW's residence time of about 3,000 years in the regional volcanic bedrock aquifer system and upslope of La Selva (Genereux et al, ) affords ample time to remove DOM's fluorescence properties as well as produce DOM exhibiting SUVA 254 values <1 L mg C −1 m −1 and S R values >5.…”

Section: Discussionmentioning

confidence: 49%

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Regional Groundwater and Storms Are Hydrologic Controls on the Quality and Export of Dissolved Organic Matter in Two Tropical Rainforest Streams, Costa Rica

et al. 2018

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A paired‐watershed approach was used to compare the quality and fluxes of dissolved organic matter (DOM) during stormflow and baseflow in two lowland tropical rainforest streams located in northeastern Costa Rica. The Arboleda stream received regional groundwater (RGW) flow, whereas the Taconazo stream did not. DOM quality was assessed with absorbance and fluorescence and stable carbon isotope (δ13C‐DOC) values. RGW DOM lacked detectable fluorescence and had specific ultraviolet absorption (SUVA254) and absorbance slope ratio (SR) values consistent with low aromaticity and low molecular weight material, respectively. We attributed these properties to microbial degradation and sorption of humic DOM to mineral surfaces during transport through bedrock. SUVA254 values were lower and SR values were higher in the Arboleda stream during baseflow compared to the Taconazo stream, presumably due to dilution by RGW. However, no significant difference in SUVA254 or SR occurred between the streams during stormflow. SUVA254 was negatively correlated to δ13C‐DOC (r2 = 0.61, P < 0.001), demonstrating a strong linkage between stream DOM characteristics and the relative amounts of RGW flow and local watershed runoff containing soil and throughfall C sources. Mean DOC export from the Taconazo stream during the study period was 2.62 ± 0.39 g C m−2 year−1, consistent with other tropical streams, yet mean DOC export from the Arboleda stream was 13.79 ± 2.07 g C m−2 year−1, one of the highest exports reported and demonstrating a substantial impact of old RGW from outside the watershed boundary can have on surface water carbon cycling.

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Section: Discussionmentioning

confidence: 49%

Section: Discussionmentioning

confidence: 49%

Regional Groundwater and Storms Are Hydrologic Controls on the Quality and Export of Dissolved Organic Matter in Two Tropical Rainforest Streams, Costa Rica

et al. 2018

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Fluorescence Characterization of Natural Organic Matter at a Northern Ontario Wastewater Treatment Plant

Riopel

Siemann

2014

Water Air Soil Pollut

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Binding of Cu, Co, and Cs to fluorescent components of natural organic matter (NOM) from three contrasting sites

Hume

Siemann

2018

Environ Sci Pollut Res

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Aqueous natural organic matter (NOM) contains different types of functional groups (carboxylic, phenolic, sulfidic, etc.), and hence could change the speciation of metals in environmental systems. This work is a proof-of-concept study on the interaction of three metals (Cu, Co, and Cs) with NOM using fluorescence spectroscopy. The specific aim was to determine the conditional stability constants for these three metals with NOM optical components, obtained from the quenching of fluorescence signals. Three contrasting water types were sampled in Northern Ontario: a pristine source (Cross Rd.), an urban-impacted source (Junction Creek), and an industrially impacted creek (Copper Cliff creek). In this investigation, Cu was used as a benchmark, whereas Co and Cs analyses were novel applications of this technique. Humic-like (H-like; terrestrial and microbial), fulvic-like (F-like), and protein-like (P-like) fluorescence components were found in various proportions at the three sampling sites. For these samples, the fluorescence signals of the H-, F-, and P-like components were quenched upon additions of Cu. The computed conditional stability constants (as log K) ranged from 4.46 to 6.06. In contrast, K values with Co were measurable only for the two H-like components of the pristine sample (log K 3.02-4.05). Cesium (Cs) induced quenching only for the P-like component at the industrial-impacted site (log K 4.82-5.03). While this study corroborates earlier reports that Cu-NOM interactions can be measured by fluorescence, we are showing for the first time a direct chemical interaction of Co and Cs with specific NOM components, as reported by fluorescence quenching.

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Fluorescence characterization of the natural organic matter in deep ground waters from the Canadian Shield, Ontario, Canada

Cited by 7 publications

References 28 publications

Regional Groundwater and Storms Are Hydrologic Controls on the Quality and Export of Dissolved Organic Matter in Two Tropical Rainforest Streams, Costa Rica

Regional Groundwater and Storms Are Hydrologic Controls on the Quality and Export of Dissolved Organic Matter in Two Tropical Rainforest Streams, Costa Rica

Fluorescence Characterization of Natural Organic Matter at a Northern Ontario Wastewater Treatment Plant

Binding of Cu, Co, and Cs to fluorescent components of natural organic matter (NOM) from three contrasting sites

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