TY - JOUR
T1 - Evaluating the ameliorative effect of natural dissolved organic matter (DOM) quality on copper toxicity to daphnia magna
T2 - Improving the BLM
AU - Al-Reasi, Hassan A.
AU - Smith, D. Scott
AU - Wood, Chris M.
N1 - Funding Information:
Acknowledgments 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. NSERC also provided support to DSS.
PY - 2012/3
Y1 - 2012/3
N2 - Various quality predictors of seven different natural dissolved organic matter (DOM) and humic substances were evaluated for their influence on protection of Daphnia magna neonates against copper (Cu) toxicity. Protection was examined at 3 and 6 mg l-1 of dissolved organic carbon (DOC) of each DOM isolate added to moderately hard, dechlorinated water. Other water chemistry parameters (pH, concentrations of DOC, calcium, magnesium and sodium) were kept relatively constant. Predictors included absorbance ratios Abs 254/365 (index of molecular weight) and Abs-octanol 254/Abs-water254 (index of ipophilicity), specific absorption coefficient (SAC340; index of aromaticity), and fluorescence index (FI; index of source). In addition, the fluorescent components (humic-like, fulviclike, tryptophan-like, and tyrosine-like) of the isolates were quantified by parallel factor analysis (PARAFAC). Up to 4-fold source-dependent differences in protection were observed amongst the different DOMs. Significant correlations in toxicity amelioration were found with Abs 254/365, Abs-octanol254/Abs-water254, SAC340, and with the humiclike fluorescent component. The relationships with FI were not significant and there were no relationships with the tryptophan-like or tyrosine-like fluorescent components at 3 mg C l-1, whereas a negative correlation was seen with the fulvic-like component. In general, the results indicate that larger, optically dark, more lipophilic, more aromatic DOMs of terrigenous origin, with higher humic-like content, are more protective against Cu toxicity. A method for incorporating SAC340 as a DOM quality indicator into the Biotic Ligand Model is presented; this may increase the accuracy for predicting Cu toxicity in natural waters.
AB - Various quality predictors of seven different natural dissolved organic matter (DOM) and humic substances were evaluated for their influence on protection of Daphnia magna neonates against copper (Cu) toxicity. Protection was examined at 3 and 6 mg l-1 of dissolved organic carbon (DOC) of each DOM isolate added to moderately hard, dechlorinated water. Other water chemistry parameters (pH, concentrations of DOC, calcium, magnesium and sodium) were kept relatively constant. Predictors included absorbance ratios Abs 254/365 (index of molecular weight) and Abs-octanol 254/Abs-water254 (index of ipophilicity), specific absorption coefficient (SAC340; index of aromaticity), and fluorescence index (FI; index of source). In addition, the fluorescent components (humic-like, fulviclike, tryptophan-like, and tyrosine-like) of the isolates were quantified by parallel factor analysis (PARAFAC). Up to 4-fold source-dependent differences in protection were observed amongst the different DOMs. Significant correlations in toxicity amelioration were found with Abs 254/365, Abs-octanol254/Abs-water254, SAC340, and with the humiclike fluorescent component. The relationships with FI were not significant and there were no relationships with the tryptophan-like or tyrosine-like fluorescent components at 3 mg C l-1, whereas a negative correlation was seen with the fulvic-like component. In general, the results indicate that larger, optically dark, more lipophilic, more aromatic DOMs of terrigenous origin, with higher humic-like content, are more protective against Cu toxicity. A method for incorporating SAC340 as a DOM quality indicator into the Biotic Ligand Model is presented; this may increase the accuracy for predicting Cu toxicity in natural waters.
KW - Absorbance and fluorescence quality parameters
KW - Biotic ligand model
KW - Copper
KW - Daphnia magna
KW - Dissolved organic matter
UR - http://www.scopus.com/inward/record.url?scp=84861683903&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84861683903&partnerID=8YFLogxK
U2 - 10.1007/s10646-011-0813-z
DO - 10.1007/s10646-011-0813-z
M3 - Article
C2 - 22072428
AN - SCOPUS:84861683903
SN - 0963-9292
VL - 21
SP - 524
EP - 537
JO - Ecotoxicology
JF - Ecotoxicology
IS - 2
ER -