TY - JOUR
T1 - Physicochemical and spectroscopic properties of natural organic matter (NOM) from various sources and implications for ameliorative effects on metal toxicity to aquatic biota
AU - Al-Reasi, Hassan A.
AU - Wood, Chris M.
AU - Smith, D. Scott
N1 - Funding Information:
Hassan A. Al-Reasi is supported by a doctoral scholarship from the Government of Oman . This work was funded by a Discovery grant from the Natural Sciences and Engineering Research Council of Canada (NSERC) to CMW, who is supported by the Canada Research Chair program. Dr. Jim McGeer and his student, K. Hicks, and C. Gheorghiu from DSS's lab are thanked for their participation in sample collection and measurements. We gratefully acknowledge personnel in the laboratory of the late R.C. Playle, Department of Biology, Wilfrid Laurier University for the use of their published characterization data of many NOM samples.
PY - 2011/6
Y1 - 2011/6
N2 - Natural organic matter (NOM), expressed as dissolved organic carbon (DOC in mgCL-1), is an ubiquitous complexing agent in natural waters, and is now recognized as an important factor mitigating waterborne metal toxicity. However, the magnitude of the protective effect, judged by toxicity measures (e.g. LC50), varies substantially among different NOM sources even for similar DOC concentrations, implying a potential role of NOM physicochemical properties or quality of NOM. This review summarizes some key quality parameters for NOM samples, obtained by reverse osmosis, and by using correlation analyses, investigates their contribution to ameliorating metal toxicity towards aquatic biota. At comparable and environmentally realistic DOC levels, molecular spectroscopic characteristics (specific absorbance coefficient, SAC, and fluorescence index, FI) as well as concentrations of fluorescent fractions obtained from mathematical mixture resolution techniques (PARAFAC), explain considerable variability in the protective effects. NOM quality clearly influences the toxicity of copper (Cu) and lead (Pb). NOM quality may also influence the toxicity of silver (Ag), cadmium (Cd) and inorganic mercury (Hg), but as yet insufficient data are available to unequivocally support the latter correlations between toxicity reduction and NOM quality predictors. Cu binding capacities, protein-to-carbohydrate ratio, and lipophilicity, show insignificant correlation to the amelioration offered by NOMs, but these conclusions are based on data for Norwegian NOMs with very narrow ranges for the latter two parameters. Certainly, various NOMs alleviate metal toxicity differentially and therefore their quality measures should be considered in addition to their quantity.
AB - Natural organic matter (NOM), expressed as dissolved organic carbon (DOC in mgCL-1), is an ubiquitous complexing agent in natural waters, and is now recognized as an important factor mitigating waterborne metal toxicity. However, the magnitude of the protective effect, judged by toxicity measures (e.g. LC50), varies substantially among different NOM sources even for similar DOC concentrations, implying a potential role of NOM physicochemical properties or quality of NOM. This review summarizes some key quality parameters for NOM samples, obtained by reverse osmosis, and by using correlation analyses, investigates their contribution to ameliorating metal toxicity towards aquatic biota. At comparable and environmentally realistic DOC levels, molecular spectroscopic characteristics (specific absorbance coefficient, SAC, and fluorescence index, FI) as well as concentrations of fluorescent fractions obtained from mathematical mixture resolution techniques (PARAFAC), explain considerable variability in the protective effects. NOM quality clearly influences the toxicity of copper (Cu) and lead (Pb). NOM quality may also influence the toxicity of silver (Ag), cadmium (Cd) and inorganic mercury (Hg), but as yet insufficient data are available to unequivocally support the latter correlations between toxicity reduction and NOM quality predictors. Cu binding capacities, protein-to-carbohydrate ratio, and lipophilicity, show insignificant correlation to the amelioration offered by NOMs, but these conclusions are based on data for Norwegian NOMs with very narrow ranges for the latter two parameters. Certainly, various NOMs alleviate metal toxicity differentially and therefore their quality measures should be considered in addition to their quantity.
KW - Aquatic organisms
KW - Metal toxicity
KW - Natural organic matter
KW - Physicochemical characteristics
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U2 - 10.1016/j.aquatox.2011.02.015
DO - 10.1016/j.aquatox.2011.02.015
M3 - Review article
C2 - 21470554
AN - SCOPUS:79953256804
SN - 0166-445X
VL - 103
SP - 179
EP - 190
JO - Aquatic Toxicology
JF - Aquatic Toxicology
IS - 3-4
ER -