Common occurrence of a positive δ53Cr shift in Central European waters contaminated by geogenic/industrial chromium relative to source values.
Carcinogenic effects of hexavalent chromium in waters are of concern in many countries worldwide. We explored Cr isotope systematics at 11 sites in the Czech Republic and Poland. Geogenic Cr pollution was associated with serpentinite bodies at former convergent plate margins, while anthropogenic Cr pollution resulted from electroplating, tanning, and the chemical industry. Cr(VI) concentration in geogenic waters was less than 40 ppb. Anthropogenic waters contained up to 127,000 ppb Cr(VI). At both geogenic and anthropogenic sites, where known, the source of pollution had a low δ53Cr (<1‰). δ53Cr of geogenic and anthropogenic waters was up to 3.9 and 5.8‰, respectively. At both serpentinite-dominated and industrial sites, δ53Cr(VI)aq was shifted toward higher values, compared to the pollution source. At the industrial sites, this positive δ53Cr shift was related to Cr(VI) reduction, a process known to fractionate Cr isotopes. At geogenic sites, the origin of high δ53Cr(VI)aq is tentatively ascribed to preferential release of 53Cr during oxidation of soil Cr(III) and its mobilization to water. δ53Cr(VI) of industrially contaminated waters was significantly higher (p<0.001) compared to δ53Cr of waters carrying geogenic Cr(VI), implying that either the effective fractionation factor or process extent was greater for Cr(VI) reduction than for Cr(III) oxidation.
Division of Geochemistry and Laboratories, Czech Geological Survey , Geologicka 6, 152 00 Prague 5, Czech Republic.
Martin
M
Novak
Vladislav
V
Chrastny
Eva
E
Cadkova
Juraj
J
Farkas
Thomas D
TD
Bullen
Jiri
J
Tylcer
Zdenka
Z
Szurmanova
Marcel
M
Cron
Eva
E
Prechova
Jan
J
Curik
Marketa
M
Stepanova
Jan
J
Pasava
Lucie
L
Erbanova
Marie
M
Houskova
Karel
K
Puncochar
Lucas A
LA
Hellerich
D002857:Chromium / Q000032:analysis* / Q000737:chemistry; D002859:Chromium Isotopes / Q000032:analysis* / Q000737:chemistry; D018153:Czech Republic; D004787:Environmental Pollution / Q000032:analysis*; D007220:Industrial Waste / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D002859:Chromium Isotopes; D007220:Industrial Waste; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion