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Environmental fate of nonylphenol ethoxylates: Differential adsorption of homologs to components of river sediment
Author(s) -
John Dominic M.,
House W. Alan,
White Graham F.
Publication year - 2000
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.5620190207
Subject(s) - adsorption , nonylphenol , chemistry , sediment , environmental chemistry , partition coefficient , kaolinite , sewage sludge , chromatography , sewage , organic chemistry , mineralogy , environmental engineering , environmental science , geology , paleontology
Nonylphenol ethoxylate (NPEO x ) homologs present in commercial mixtures were rapidly adsorbed to and desorbed from native river sediment. Adsorption isotherms, established using high‐performance liquid chromatography analysis to monitor individual homologs NPEO 3 to NPEO 13 simultaneously, were linear for each component adsorbing to native sediment, organic‐free sediment, and kaolinite, usually with small positive intercepts on the isotherms indicating an additional low‐capacity, high‐affinity binding site. The adsorption partition coefficients ( K d ) for the native sediment decreased progressively from 1,460 L/kg for NPEO3 to 450 L/kg for NPEO 10 , then increased again slightly for higher homologs. In contrast, K d values for organic‐free sediment (range 230–590 L/kg) or kaolinite (190–490 L/kg) increased steadily from NPEO 3 to NPEO 13 . Adsorptions to silica and alumina were very weak, but to sewage sludge all components adsorbed strongly ( K d values 12,000–33,000, with a maximum at NPEO 7 ). The adsorption to sewage sludge was related to the low‐capacity, high‐affinity sites observed for native sediment. Dependence of K d values on ethoxylate chain length was analyzed, in terms of both possible adsorption mechanisms, and the environmental fate and impact of NPEO x s as endocrine disruptors.