The influence of dissolved natural organic matter (NOM) source on copper toxicity was investigated with larval fathead minnows (Pimephales promelas) in reconstituted moderately hard water. Ninety-six-hour static renewal toxicity tests were conducted to investigate an assumption of the biotic ligand model (BLM) that NOM source does not need to be considered to adequately predict copper toxicity. The nine different NOM isolates used in these toxicity tests were chemically well-characterized substances that were obtained by reverse osmosis as part of an NOM typing project based in southern Norway. Three median lethal concentration (LC50) values were estimated for toxicity tests conducted with each NOM, at nominal dissolved organic carbon (DOC) concentrations of 2, 5, and 10 mg/L. Tests also were conducted in dilution waters in which no NOM was added. Regression analyses were conducted to compare NOM-specific (specific NOM source) LC50s versus DOC concentration relationships to each other, as well as to the overall LC50 versus DOC concentration relationship. Statistical differences were found regarding the effects of NOM source on copper toxicity. Similar analyses were conducted with humic acid (HA) concentrations and spectral absorbance, and differences in the effect of NOM source on copper toxicity were similarly concluded. These results do not support the assumption that copper toxicity can be adequately predicted by utilizing DOC concentration, regardless of NOM source. Evaluation of relationships between LC50 values and other NOM characteristics revealed that despite significant differences due to NOM source on copper toxicity, DOC and HA concentrations were the most effective parameters in explaining variability in LC50 values. When BLM-predicted LC50 values were compared to observed LC50 values, predicted values showed reasonable agreement with observed values, but some deviations occurred due to NOM source and DOC concentration.
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Environ Sci Process Impacts
January 2025
College of Environment, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
JMIR Cancer
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Chom-rom-nom-yen, Breast Cancer Survivors Support Group, Songklanagarind Hospital, Prince of Songkla University, Songkhla, Thailand.
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Water Res
March 2025
School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China. Electronic address:
Lignin- and tannin-like phenolic compounds are shown to be the major compositions of electron donating moieties (EDM) of aquatic natural organic matter (NOM). However, little is known about the compositions of EDMs within effluent organic matter (EfOM). In the present study, chlorine dioxide (ClO) was used as a selectively oxidative probe to investigate the difference in the molecular composition of EDM between NOM and EfOM due to its high selectivity towards electron-rich compounds.
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Bayer Crop Science, St. Louis, MO, USA 63141-7843.
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LG Chem Japan Co., Ltd., Kyobashi Trust Tower 12F, 2-1-3 Kyobashi Chuo-ku, Tokyo 104-0031, Japan.
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