Chromium Manufacturer

In the past decades the increased use of  Chromium Manufacturer (Cr) in several anthropogenic activities and consequent contamination of soil and water have become an increasing concern. Cr exists in several oxidation states but the most stable and common forms are Cr(0), Cr(III) and Cr(VI) species. Cr toxicity in plants depends on its valence state. Cr(VI) as being highly mobile is toxic, while Cr(III) as less mobile is less toxic. Cr is taken up by plants through carriers of essential ions such as sulphate. Cr uptake, translocation, and accumulation depend on its speciation, which also conditions its toxicity to plants. Symptoms of Cr toxicity in plants are diverse and include decrease of seed germination, reduction of growth, decrease of yield, inhibition of enzymatic activities, impairment of photosynthesis, nutrient and oxidative imbalances, and mutagenesis.

Chromium Manufacturer  in Water
Chromium may enter the natural waters by weathering of Cr-containing rocks, direct discharge from industrial operations, leaching of soils, among others. In the aquatic environment Cr may suffer reduction, oxidation, sorption, desorption, dissolution, and precipitation [6].

The aqueous solubility of Cr(III) is a function of the pH of the water. Under neutral to basic pH, Cr(III) will precipitate and conversely under acidic pH it will tend to solubilize. The forms of Cr(VI) chromate and dichromate are extremely soluble under all pH conditions, but they can precipitate with divalent cations [6]. The recommended limits for Cr concentration in water are 8 μg L−1 for Cr(III) and 1 μg L−1 for Cr(VI). In the effluents in the vicinity of Cr industries the levels of Cr range from 2 to 5 g L−1

Chromium Manufacturer  in Plants

The pathway of Cr uptake in plants is not yet clearly elucidated. However, being a nonessential element, Cr does not have any specific mechanism for its uptake and is also dependent on Cr speciation. Plant uptake of Cr(III) is a passive process, that is, no energy expenditure is required by the plant [3, 18]. The uptake of Cr(VI) is thought to be an active mechanism performed by carriers for the uptake of essential elements such as sulphate [19, 20]. Cr also competes with Fe, S, and P for carrier binding .Chromium Manufacturer Chromium Manufacturer Chromium Manufacturer

Cr(VI) has higher solubility and thus bioavailability is more toxic at lower concentrations than Cr(III), which tends to form stable complexes in the soil [17]. There are conflicting results concerning the uptake and translocation of Cr(VI). While some authors defend that Cr(VI) is reduced to Cr(III) on the root surface [21, 22], others suggest that dissolved Cr(VI) is taken up by plants without reduction [23].

Thus, Cr toxicity is dependent on metal speciation, which is determinant for its uptake, translocation, accumulation. Cr is toxic for agronomic plants at about 0.5 to 5.0 mgm L−1 in nutrient solution and 5 to 100 mg g−1 in soil [24]. Under normal conditions, concentration of Cr in plants is less than 1 μg g−1