Rates of Hexavalent Chromium Reduction in Anoxic Estuarine Sediments: pH Effects and the Role of Acid Volatile Sulfides

2010 ◽  
Vol 44 (1) ◽  
pp. 136-142 ◽  
Author(s):  
Andrew M. Graham ◽  
Edward J. Bouwer
Keyword(s):  
Hexavalent Chromium ◽  
Estuarine Sediments ◽  
Ph Effects ◽  
Chromium Reduction ◽  
Acid Volatile Sulfides

The role of iron in hexavalent chromium reduction by municipal landfill leachate

2009 ◽  
Vol 161 (2-3) ◽  
pp. 657-662 ◽  
Author(s):  
Yarong Li ◽  
Gary K.-C. Low ◽  
Jason A. Scott ◽  
Rose Amal
Keyword(s):  
Hexavalent Chromium ◽  
Landfill Leachate ◽  
Chromium Reduction ◽  
Municipal Landfill

Hexavalent chromium reduction by Providencia sp.

2006 ◽  
Vol 41 (6) ◽  
pp. 1332-1337 ◽  
Author(s):  
Urvashi Thacker ◽  
Rasesh Parikh ◽  
Yogesh Shouche ◽  
Datta Madamwar
Keyword(s):  
Hexavalent Chromium ◽  
Chromium Reduction

scholarly journals Golgi-Colonnier method: correlation of the degree of chromium reduction and pH change with quality of staining.

1994 ◽  
Vol 42 (3) ◽  
pp. 393-403 ◽  
Author(s):  
A Angulo ◽  
J A Merchán ◽  
M Molina
Keyword(s):  
Chromium Reduction ◽  
Ph Change ◽  
Total Chromium ◽  
Chromium Species ◽  
Cell Staining ◽  
Before And After ◽  
Neuronal Proteins ◽  
Ph Increase

We examined the role of chromium reduction in the Golgi-Colonnier method, correlating the quality of neuronal impregnation with the levels of hexavalent (CrVI) and trivalent (CrIII) chromium in the tissue and in the chromation fluid (CF). The concentrations of both chromium species were assessed by measuring spectrophotometrically the CrVI before and after oxidizing the sample and by calculating the ratio of CrVI to total chromium (chromium ratio, CrR). The CrR was almost identical in the tissue and the CF, decreasing exponentially during chromation due to a progressive consumption of CrVI to form CrIII. Satisfactory cell impregnation was obtained only when the CrR was 0.45-0.7, regardless of other factors. The CrR values could be accurately predicted by the pH increase of the CF; this increase has proven to be a most reliable criterion to decide the endpoint of the chromation process. The dependence of cell staining on the [CrIII], together with the well-known ability of this species to bridge proteins, suggests that the key event for cell impregnation is the cross-linking of neuronal proteins by CrIII polymers.

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