@article{fdi:010035723,
  title = {{T}race element fractionation and transport in boreal rivers and soil porewaters of permafrost-dominated basaltic terrain in {C}entral {S}iberia},
  author = {{P}okrovsky, {O}. {S}. and {S}chott, {J}. and {D}upr{\'e}, {B}ernard},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he chemical status of similar to 40 major and trace elements ({TE}) and organic carbon ({OC}) in pristine boreal rivers draining the basaltic plateau of {C}entral {S}iberia ({P}utorana) and interstitial solutions of permafrost soils was investigated. {W}ater samples were filtered ill the field through progressively decreasing pore size (5 mu m -> 0.22 mu m -> 0.025 mu m -> 10 k{D}a -> 1 k{D}a) using cascade frontal filtration technique. {M}ost rivers and soil porewaters exhibit 2-5 times higher than the world average concentration of dissolved (i.e., < 0.22 mu m) iron (0.03-0.4 mg/{L}), aluminum (0.03-0.4 mg/{L}), {OC} (10-20 mg/{L}) and various trace elements that are usually considered as immobile in weathering processes ({T}i, {Z}r, {G}a, {Y}, {REE}s). {U}ltrafiltration revealed strong relationships between concentration of {TE} and that of colloidal {F}e and {A}l. {A}ccording to their partition during filtration and association with colloids, two groups of elements can be distinguished: (i) those weakly dependent on ultrafiltration and that are likely to be present as truly dissolved inorganic species ({L}i, {N}a, {K}, {S}i, {M}n, {M}o, {R}b, {C}s, {A}s, {S}b) or, partially (20-30%) associated with small size {F}e- and {A}l-colloids ({C}a, {M}g, {S}r, {B}a) and to small (< 1-10 k{D}a) organic complexes ({C}o, {N}i, {C}u, {Z}n), and (ii) elements strongly associated with colloidal iron and aluminum ill all ultrafiltrates largely present in 1-100 k{D}a fraction ({G}a, {Y}, {REE}s, {P}b. {V}. {C}r. {T}i. {G}e, {Z}r, {T}h, {U}). {TE} concentrations and partition coefficients did not show any detectable variations between different colloidal fractions for soil porewaters, suprapermafrost flow and surface streams. {TE} concentration measurements in river suspended particles demonstrated significant contribution (i.e.. >= 30%) of conventionally dissolved (< 0.22 mu {M}) forms for usually "immobile" elements such as divalent transition metals, {C}d. {P}b. {V}, {S}ri. {Y}, {REE}s, {Z}r, {H}f, {T}h. {T}he {A}l-normalized accumulation coefficients of {TE} in vegetation litter compared to basalts achieve 10-100 for {B}. {M}n, {Z}n, {A}s. {S}r, {S}ri., {S}b, and the larch litter degradation is able to provide the major contribution to the annual dissolved flux of most trace elements. {I}t is hypothesized that the decomposition of plant litter in the topsoil horizon leads to {F}e({III})-, {A}l-organic colloids formation and serves as an important source of elements in downward percolating fluids. (c) 2006 {P}ublished by {E}lsevier {I}nc.},
  keywords = {},
  booktitle = {},
  journal = {{G}eochimica {E}t {C}osmochimica {A}cta},
  volume = {70},
  numero = {13},
  pages = {3239--3260},
  ISSN = {0016-7037},
  year = {2006},
  DOI = {10.1016/j.gca.2006.04.008},
  URL = {https://www.documentation.ird.fr/hor/fdi:010035723},
}