An FTIR-DRIFT study on river sediment particle structure: implications for biofilm dynamics and pollutant binding.
Diffuse reflectance infrared Fourier transform (DRIFT) spectrometry was applied to a set of sediment samples collected by traps over one and a half years in a mid-mountainous river. Dynamic changes in hydrological and life-cycle conditions generated sediment particles of different C(org) content and organic composition. Periods in the midst of or shortly after flood events left particles poor in C(org) content with spectral features that were enriched in carboxylic and aromatic signals. These are characteristic of terrestrial oxidized vascular plant debris. Low-flow conditions saw the consequent build-up of amide, aliphatic, and polysaccharide moieties as expected for autochthonous biofilm derived material. A peak ratio of two bands representing the alternation of these two types of organic matter showed that flood particle C(org) had a higher affinity for metals than the high C(org) of mature biofilms, probably owing to higher COO- contents in the first. The relative dietary bioavailability of the metals from sediment C(org), which is related to the nutritional value of the substrate, is therefore probably lower in the aftermath of a flood than in prolonged low-flow situations. This needs to be accounted for in future metal speciation and bioavailability modeling approaches.
Resource Centre for Environmental Technologies (CRTE), CRP-Henri Tudor, 66 rue de Luxembourg, BP 144 L-4002 Esch-sur-Alzette, Grand Duchy of Luxembourg. tom.galle@tudor.lu
Tom
T
Gallé
Barend
B
Van Lagen
Andreas
A
Kurtenbach
Reinhard
R
Bierl
D000327:Adsorption; D018441:Biofilms / Q000254:growth & development*; D002244:Carbon / Q000032:analysis; D016000:Cluster Analysis; D003300:Copper / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000032:analysis*; D008670:Metals / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis; D010316:Particle Size; D015203:Reproducibility of Results; D045483:Rivers / Q000737:chemistry*; D044444:Scenedesmus; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis*; D015032:Zinc / Q000032:analysis
D008670:Metals; D014874:Water Pollutants, Chemical; D002244:Carbon; D003300:Copper; D015032:Zinc; D009584:Nitrogen