Antifungal efficiency assessment of the TiO2 coating on façade paints

The work studies the photocatalytic activity and the antifungal efficiency of the TiO₂/Zn-Al coatings placed on the target commercial façade paints. The photocatalytic active nanocomposite based on TiO₂ and Zn-Al-layered double hydroxides (ZnAl-LDHs) was synthesized by a wet impregnation technique with 3 % w/w TiO₂. The freshly prepared suspension was applied by spray technique on the surfaces of the white façade paints. The goal of the work was to develop a method that quickly quantifies the antifungal activity of the commercial façade paints with and without biocidal components covered with a photocatalytic coating. The essence of the proposed method is the monitoring of the fungal growth (artificial ageing conditions) and the quantification of its development (UV-A 0.13 mWcm^?2) on the façade paint surfaces. A special fungus nutrient (potato dextrose agar (PDA)) was inoculated with the spores of the Aspergillus niger ATCC 6275, and the test samples (façade paints with and without photocatalytic coating) were placed on the inoculated nutrient in the petri dishes. The images of the fungal growth on the samples of the facade paints, during a period of 5 days, were imported into Matlab R2012a where they were converted to binary images (BW), based on the adequate threshold. The percentage of the surface coverage was calculated by applying the specifically written program code which determines the ratio of the black and white pixels. The black pixels correspond to the surface covered with hyphae and mycelia of the fungus.     

Removal of PCBs from a Contaminated Soil Using CF-Systems® Solvent Extraction Process

ABSTRACT

The U.S. Environmental Protection Agency’s (EPA) Superfund Technical Assistance Response Team (START) in cooperation with EPA’s Superfund Innovative Technology Evaluation (SITE) program evaluated a pilot scale solvent extraction process developed by CF-Systems. This process uses liquefied propane to extract organic contaminants from soils, sludges, and sediments. A pilot-scale evaluation was conducted in Golden, CO at Hazen Research, Inc., using CF-Systems’ trailer-mounted organics extraction unit. Approximately 1,000 pounds of soil, with an average poly-chlorinated biphenyl (PCB) concentration of 260 mg/kg, was obtained from a remote Superfund site. Six 100-pound batches of the contaminated soil were extracted using multiple extraction sequences. Three of the six batch runs were subjected to three extraction sequences each, so that process variability could be evaluated. Results showed that PCB removal efficiencies varied between 91.4 and 99.4%, with the propane-extracted soils retaining low concentrations of PCBs (19.0–1.8 mg/kg). Removal efficiencies of oil and grease (O&G) were found to be 96.0 to 99.6% with propane-extracted soils retaining O&G concentrations from 279 to <20 mg/kg. Overall extraction efficiency was found to be dependant upon the numberof extraction cycles used.     

Ectopic expression of Arabidopsis ABC transporter MRP7 modifies cadmium root-to-shoot transport and accumulation

Arabidopsis MRPs/ABCCs have been shown to remove various organic and inorganic substrates from the cytosol to other subcellular compartments. Here we first demonstrate that heterologous expression of AtMRP7 in tobacco (Nicotiana tabacum var. Xanthi) modifies cadmium accumulation, distribution and tolerance. Arabidopsis MRP7 was localized both in the tonoplast and in the plasma membrane when expressed in tobacco. Its overexpression increased tobacco Cd-tolerance and resulted in enhanced cadmium concentration in leaf vacuoles, indicating more efficient detoxification by means of vacuolar storage. Heterologous AtMRP7 expression also led to more efficient retention of Cd in roots, suggesting a contribution to the control of cadmium root-to-shoot translocation. The results underscore the use of AtMRP7 in plant genetic engineering to modify the heavy-metal accumulation pattern for a broad range of applications.