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Binding interactions of 1‐naphthol with dissolved organic matter of Lake Biwa and treated sewage wastewater: The role of microbial fulvic acid
Author(s) -
Ahmed Tanveer,
Ohta Keiichi,
Nagafuchi Osamu,
Maruo Masahiro
Publication year - 2012
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.1934
Subject(s) - dissolved organic carbon , chemistry , environmental chemistry , effluent , organic matter , fulvic acid , fluorescence spectroscopy , absorbance , fluorescence , humic acid , chromatography , environmental engineering , organic chemistry , environmental science , fertilizer , physics , quantum mechanics
The binding interactions of 1‐naphthol with effluent and whole natural dissolved organic matter (DOM) samples were analyzed by using a fluorescence quenching technique. Nonfractionated DOM samples from Lake Biwa (Japan), creek water, treated sewage effluents, and an extracted Lake Biwa fulvic acid (LBFA) standard were used as quenchers and compared at the same 1‐naphthol with DOM organic carbon ratios found for low natural dissolved organic carbon (DOC) levels (∼4.5 mg/L). Natural and effluent DOM (eDOM) samples were characterized by the DOC level, relative hydrophobicity (RH%), ultraviolet (UV)‐visible absorbance and fluorescence excitation emission spectroscopy. These parameters were compared with those of the reference LBFA standard. Concave‐up Stern‐Volmer plots accounted for both the partitioning and the adsorptive binding in the eDOM–polycyclic aromatic hydrocarbons (PAH) system as compared with the nonspecific partitioning in the natural DOM‐PAH system. Strong linear regressions ( r 2 > 0.80) between the log K DOC values, the RH%, the UV absorbances, and the Fl 340‐435 ‐UV 340 indices for the structural composition and molecular weights of the DOM samples were obtained. These results suggest that low molecular weight microbial fulvic acid (<800 Da) is dominant in the eDOM‐PAH binding interactions, as well as in the distinct molecular structure of the eDOM samples, which resulted in fivefold to sixfold higher binding magnitude for 1‐naphthol than for the other samples. Environ. Toxicol. Chem. 2012; 31: 2201–2209. © 2012 SETAC