Temporal changes in Cr fluxes and d53Cr values in runoff from a small serpentinite catchment (Slavkov Forest, Czech Republic)

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F17%3A00000188" target="_blank" >RIV/00025798:_____/17:00000188 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1016/j.chemgeo.2017.09.023" target="_blank" >http://dx.doi.org/10.1016/j.chemgeo.2017.09.023</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.chemgeo.2017.09.023" target="_blank" >10.1016/j.chemgeo.2017.09.023</a>

Result language

angličtina

Original language name

Temporal changes in Cr fluxes and d53Cr values in runoff from a small serpentinite catchment (Slavkov Forest, Czech Republic)

Original language description

Headwater catchments underlain by ultramafic bedrock may release toxic amounts of hexavalent chromium [Cr(VI)] into runoff. Redox cycling of Cr during weathering, pedogenesis and runoff generation can be constrained by studying 53Cr/52Cr isotope systematics. We report a 12-month time-series of d53Cr values of runoff from a small serpentinite-dominated catchment in Central Europe, complemented with a 5-year monitoring of Cr and DOC concentrations. d53Cr values of bulk bedrock, rock-forming minerals, and bulk soil were also determined. Cr(VI) concentrations in runoff exceeded the 10-ppb maximum contaminant level by 70 %. Concentrations of Cr(VI) in runoff were positively correlated with water discharge and DOC concentrations. Chromium export flux in winter was significantly higher than in summer. Runoff d53Cr exhibited a temporal trend, with negative values (-0.6 ‰) in winter and positive values (0.5 ‰) in summer. On an annual basis, the mass-weighted d53Cr value of runoff was -0.4 ‰. Dissolved Cr exported in winter was isotopically lighter than the within-site Cr sources: d53Cr of bulk bedrock ranged from -0.2 to 0.0 ‰, and d53Cr of soil ranged from -0.2 to 0.3 ‰. Chromium isotope analysis of seven rock-forming minerals separated from serpentinites, tremolite/actinolite shists and amphibolites revealed a much wider range of d53Cr values, from -0.4 ‰ (hornblende) to 1.7 ‰ (albite). Most of the variability in runoff d53Cr can be explained by incongruent oxidative weathering, with a contribution of isotope-selective processes associated with pedogenesis. Isotopically light Cr was preferentially mobilized from weathered bedrock and soil in cold, water-rich periods and exported via stream water. In these periods, precipitation water more rapidly penetrates into the soil than in summer months, characterized by lower rainfall and larger evapotranspiration, and more efficiently leaches the accumulated Cr(VI).

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10618 - Ecology

Project

<a href="/en/project/GA15-21373S" target="_blank" >GA15-21373S: Isotope mass balance for chromium-contaminated sites based on 53Cr/52Cr ratios of solid and liquid samples</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2017

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Chemical Geology

ISSN

0009-2541

e-ISSN

—

Volume of the periodical

472

Issue of the periodical within the volume

November

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

9

Pages from-to

22-30

UT code for WoS article

000414191700003

EID of the result in the Scopus database

2-s2.0-85030750767