Chromium reduction by Escherichia coli ATCC 33456 quantitatively transferred hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III). The reduced chromium was predominantly present in the external medium. Supernatant fluids of cell extract, obtained by centrifugation at 12,000 and 150,000 x g, showed almost the same Cr(VI) reduction activity, indicating that Cr(VI) reduction by E. coli ATCC...

Chromium has been and is extensively used worldwide in multiple industrial processes and is routinely discharged to the environment from such processes. Therefore, this heavy metal is a potential threat to the environment and to public health, primarily because it is non-biodegradable and environmentally persistent. Chromium exists in several oxidation states, the most stable of which are triva...

Chromium exists usually in the (III) or (VI) oxidation states. In contrast to Cr(III), which is essential to mammalian systems, Cr(VI) is dangerous for humans due to its toxicity and carcinogenic properties. Cr(VI) compounds are highly soluble, mobile and bioavailable compared to Cr(III) species. Chromium is usually analyzed using instrumental methods such as AAS or ICP, which are accurate and ...

High levels of hexavalent chromium (Cr(VI)) in groundwater are typically attributed to anthropogenic sources. However, scientific reports over the last decade have demonstrated that relatively high levels of Cr(VI) in groundwater may also be due to natural processes. Cr(VI) is among the most significant groundwater contaminants, since it is a potential carcinogenic compound that is commonly fou...

BACKGROUND The current study evaluates the mortality of 2,354 workers first employed at a Baltimore chromate production plant between 1950 and 1974. METHODS The National Death Index (NDI Plus) was used to determine vital status and cause of death. Cumulative chromium (VI) exposure and nasal and skin irritation were evaluated as risk factors for lung cancer mortality. RESULTS There are 91,18...

Large-scale industrial use of chromium(VI) has resulted in widespread contamination with carcinogenic chromium(VI). The abilities of microorganisms to survive in these environments and to detoxify chromate require the presence of specific resistance systems. Here we report identification of the transposon-located (TnOtChr) chromate resistance genes from the highly tolerant strain Ochrobactrum t...

In the different compartments of the environmental chromium occurs mainly in the oxidation states (III) and (VI). Although Cr(III) is an essential trace element for humans, Cr(VI) is highly cancerogenic and mutagenic. It is, therefore, necessary for risk assessment not only to determine total chromium, but also to determine chromium species, especially Cr(VI). Hexavalent chromium can be determi...

Biosorption is a process, which represents a biotechnological innovation as well as a cost effective excellent tool for removing heavy metals from aqueous solutions. The kinetics and equilibrium of the biosorption of Chromium (VI) from aqueous solution were investigated using immobilized mixed biosorbents of Annona squamosa seeds and Aspergillus niger in a batch system. The biosorption characte...

A fast, simple, and reliable method for determination of hexavalent chromium species in soil aqueous and alkaline extracts has been developed. The procedure is based on the ion-pair extraction of Cr(VI) with methyltrioctylammonium chloride (Aliquat 336) into xylene. The extract is analyzed by flame (FAAS) or electrothermal atomic absorption spectrometry (ETAAS). The method allows the detection ...

Chromium contamination in the area of the Radomka river basin in Poland has lead to significant environmental problems. Therefore, chromium redox transformations were investigated in the aquatic environment under conditions as close to natural as possible at intermediate pH and in the presence of original bottom sediment and dissolved oxygen. Reduction of Cr(VI) in the Radomka river water occur...