@article{fdi:010053196,
  title = {{T}racing source and evolution of suspended particles in the {R}io {N}egro {B}asin ({B}razil) using chemical species of iron},
  author = {{A}llard, {T}. and {W}eber, {T}. and {B}ellot, {C}. and {D}amblans, {C}. and {B}ardy, {M}. and {B}ueno, {G}. and {N}ascimento, {N}. {R}. and {F}ritsch, {E}mmanuel and {B}enedetti, {M}. {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}uspended solids found in porewaters obtained in waterlogged soil sequences that included representative laterite-podzol transitions, associated brooks and major rivers of the {R}io {N}egro watershed ({B}razil) were studied using electron paramagnetic resonance ({EPR}) and {F}ourier-transform infrared spectroscopies. {T}he main goal was to ascertain sources and track the evolution of suspended matter using a ubiquitous chemical species, {F}e{III} complexed to organic matter ({F}e{OM}). {T}hree size fractions were separated by tangential-flow (ultra)filtration: particulate (>0.2 mu m), dense ({P}) and light ({P}s), and colloidal (5 k{D}<{C}ol.<0.2 mu m) fractions. {Q}uantitative results were acquired for {C}ol. and {P}s fractions which are predominantly organic in nature. {F}e{OM} concentration (in parts per thousand dry weight) was determined to be relatively low in suspended solids found in black waters from podzol porewaters and brooks whereas in the main rivers it was several times higher. {F}e{OM} concentrations were also correlated with {F}e({II})/{F}e({III}) ratios in solution; these ratios were high in podzol porewaters and low in the rivers. {C}onsidering that organic complexation of {F}e({II}) is minor when compared to that of {F}e({III}), two interpretations were proposed to account for the above observation. {F}irst, [{F}e{OM}] was assumed to be distributed along a mixing line, with the clear waters from laterites and the black waters from podzols being its end-members. {C}onsequently, [{F}e{OM}] can be used to trace the source of suspended material. {S}econd, dissolved {F}e({II}) from podzol areas was considered to be progressively oxidized as pore waters move towards the mainstream. {A}ccording to this mechanism, iron is complexed by organic matter or precipitated as oxides, thus producing an evolution of colloidal matter. {A}s a result of these mechanisms' action, both the high production of {F}e({II}) and organic matter at the waterlogged podzol-laterite transition areas are major factors affecting iron export in the {R}io {N}egro watershed.},
  keywords = {{I}ron ; {C}olloids ; {O}rganic matter ; {A}mazon {B}asin ; {EPR} ; {P}odzol},
  booktitle = {},
  journal = {{C}hemical {G}eology},
  volume = {280},
  numero = {1-2},
  pages = {79--88},
  ISSN = {0009-2541},
  year = {2011},
  DOI = {10.1016/j.chemgeo.2010.10.018},
  URL = {https://www.documentation.ird.fr/hor/fdi:010053196},
}