We investigated the effects of chromate (CrVI) and phosphate (P) on their uptake and translocation in As-hyperaccumulator Pteris vittata (PV). Plants were exposed to 1) 0.05 mM CrVI and 0, 0.05, 0.25 or 1.25 mM P or 2) 0.25 mM P and 0, 0.05, 0.25 or 1.25 mM CrVI for 24 h in hydroponics. PV accumulated 2,919 mg/kg Cr in the roots at CrVI0.05, and 5,100 and 3,500 mg/kg P in the fronds and roots a...

We investigated the effects of chromate (CrVI) and phosphate (P) on their uptake and translocation in As-hyperaccumulator Pteris vittata (PV). Plants were exposed to 1) 0.10 mM CrVI and 0, 0.25, 1.25, or 2.50 mM P or 2) 0.25 mM P and 0, 0.50, 2.5 or 5.0 mM CrVI for 24 h in hydroponics. PV accumulated 2919 mg/kg Cr in the roots at CrVI₀.₁₀, and 5100 and 3500 mg/kg P in the fronds and roots at P₀...

The major links in the cycling of chromium in soils and in natural waters are between chromium(III) and chromium (VI). Between the larger links are lesser links involving processes of mobilization and oxidation of CrIII and reduction of CrVI. The gaps are mainly in our understanding of the factors that control these processes. If soluble CrIII is added to an "average" soil, a portion of it will...

Chromate (CrVI) reduction by sulfide was conducted in anaerobic batch experimental systems. The molar ratio of the reduced CrVI to the oxidized S(-II) was 1:1.5 during the reaction, suggesting that the product of sulfide oxidation was elemental sulfur. Under the anaerobic condition, the reaction was pseudo first order initially with respect to CrVI, but the rate was dramatically accelerated at ...

National Institute for Occupational Safety and Health method 7703 is a portable field procedure for the analysis of workplace air filter samples for hexavalent chromium (CrVI) content immediately after the samples are collected. The field method prescribes CrVI extraction from air filter samples with an ammonium sulfate/ammonium hydroxide extraction buffer using ultrasonic extraction (UE). Stro...

The oxidation of D-ribose and 2-deoxy-D-ribose by CrVI yields the aldonic acid and Cr3+ as final products when an excess of sugar over CrVI is used. The redox reaction occurs through CrVI→CrIII and CrVI→CrV→CrIII paths. The complete rate laws for the CrVI oxidation reactions are expressed by –d[CrVI]/dt = kH[H +]2 [ribose][CrVI], where kH = (5.9 ± 0.1) × 10–2 mol–3 dm9 s–1, and –d[CrVI]/dt = (k...

We investigated effects of arsenate (AsV), chromate (CrVI) and sulfate on As and Cr uptake and translocation by arsenic hyperaccumulator Pteris vittata (PV), which was exposed to AsV, CrVI and sulfate at 0, 0.05, 0.25 or 1.25 mM for 2-wk in hydroponic system. PV was effective in accumulating large amounts of As (4598 and 1160 mg/kg in the fronds and roots at 0.05 mM AsV) and Cr (234 and 12,630 ...

Heavy metals that contaminate soils and water usually exist in various oxidation states and form a number of compounds with different physical and chemical characteristics. These differences are often reflected in dramatic variation in toxicokinetic and biologic properties. Such variation in properties, critical in determining intrinsic toxicity, often causes a great deal of uncertainty in anal...

The remediation of chromium-contaminated sites requires knowledge of the processes that control the migration and transformation of chromium. Advection, dispersion, and diffusion are physical processes affecting the rate at which contaminants can migrate in the subsurface. Heterogeneity is an important factor that affects the contribution of each of these mechanisms to the migration of chromium...

Conventional soil solution sampling of species-sensitive inorganic contaminants, such as hexavalent chromium (CrVI), may induce interconversions due to disruption system equilibrium. The temporal resolution that these methods afford also be insufficient capture dynamic interactions or require time-consuming and expensive analysis. Microdialysis (MD) is emerging a minimally invasive passive meth...