The panel opened with a request to J. LaVelle (U.S. EPA) to enlarge upon his presentation of a bimodlal disposition for the plasma reduction of hexavalent chromium (and subsequent urine concentration) in an occupational group exposed to chromium. He replie(d that he did not know the size of the population that was exposed, but that the group consisted of workers at a dichromate plant, and the s...

Nine bacterial colonies were screened for the Cr(VI) removal efficiency and out of these three bacterial strains Pseudomonas putida, Pseudomonas aeruginosa and Bacillus sp. were isolated from soil and used to remove Cr(VI) from aqueous solution. The effect of time and concentrations on the removal rate of hexavalent chromium were studied using batch experiment. Maximum Cr (VI) removal was noted...

Trace measurements of the element chromium (Cr) are of interest in a wide range of applications and matrices. In the environment, Cr exists in two different oxidation states, the trivalent Cr(III) cation and hexavalent Cr(VI) anion. In mammals, Cr(III) is an essential element involved in the regulation of glucose; however, the element in its hexavalent form demonstrates mutagenic and carcinogen...

he strict corrosion-control requirements in the aerospace inT dustry were developed based on the performance of hexavalent chromium (chromates). With the recent rash of environmental regulations targeting hexavalent chromium, it is reasonable to ask what the industry’s response has been to identify acceptable replacement technologies. Does the aerospace industry take the “ostrich response,” whi...

Carcinogenic heavy metal chromium, in its hexavalent form (Cr(VI)), is spuriously used in various industrial operations because of its hardness and stability and is found in industrial effluents in concentrations much above WHO’s prescribed limit (50 mg/L). Conventional methods for removing toxic chromium ion (by chemical reduction followed by precipitation, ionexchange and adsorption on activa...

The development of hexavalent chromium remediating fibrous biocomposite mats through the immobilization of a hexavalent chromium reducing bacterial strain, Morganella morganii STB5, on the surfaces of electrospun polystyrene and polysulfone webs is described. The bacteria-immobilized biocomposite webs have shown removal yields of 93.60 and 93.79 % for 10 mg/L, 99.47 and 90.78 % for 15 mg/L and ...

Metal-on-metal bearings for total hip replacements have been introduced as an alternative to polyethylene in young and more active patients. These have, however, been shown to be prone to implant malpositioning and have been limited by some specific design features. In that context, coatings present an option to increase wear resistance by keeping the high fracture strength of the metal substra...

in this study, the adsorption of hexavalent chromium and zinc ions from the solution is investigated by raw red mud and mechanical-chemical activated red mud along with the possibility of selective reclamation of these ions from the solution. the mechanical-chemical activation of red mud was done by employing high-energy milling and subsequent acid treatment with hno3. raw red mud (rrm) and mec...