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AIM: The main objective of the study was to evaluate the limnological characteristics of rivers flowing through urban and rural areas in the upper Uruguay River basin in western Santa Catarina (SC), Brazil. METHODS: Sampling sites in the tributaries were selected along the longitudinal gradient and the different use of the soil in adjacent areas. Samples were collected bimonthly from March 2005 to August 2006. The following were analysed: depth, pH, electrical conductivity, dissolved oxygen concentration (DO), water temperature, chemical oxygen demand (COD), total alkalinity, ammonia, nitrite, nitrate and phosphorus were analysed. RESULTS: In most of the rivers analysed, we found a continuum from the spring to the river mouth that was characterised by a gradual increase in electrical conductivity, COD, phosphorus, alkalinity, nitrite and nitrate. However, an alteration from this pattern was found in rivers passing through urban areas. This deviation was due to high organic matter input poured into the rivers from these areas. CONCLUSIONS: Degraded riparian forest was observed along most of the bodies of water, which facilitates the entry of pollutants. Although the studied area suffers from intense farming activity (agriculture and livestock) and has the highest concentration of swine livestock in the country, the rivers that were most altered from their natural state were those that were influenced by sewage and industrial effluents from urban development.

The aim of this study was to assess the use of pesticides on farms located in the Lambedor River watershed in Guatambu, State of Santa Catarina, as well as to determine, by micronucleus testing, the risk of genotoxic impact. Samples from locally collected Cyprinus carpio, Hypostomus punctatus, Rhamdia quelen and Oreochromis niloticus gave evidence of a mean increase in micronuclei frequency from 6.21 to 13.78 in 1,000 erythrocytes, a clear indication of the genotoxic potenciality of pesticide residues in regional dams, and their significant contribution to local environmental contamination.

A practical and economical method was developed for the production of an antibacterial cotton fabric using zinc oxide nanostructures without the use of surface modifying agents. In this process, zinc nitrate hexahydrate and potassium hydroxide were used as starting materials and the reaction was performed at 50°C. The in situ growth of ZnO nanostructures on cotton fabric occurred in a single-stage process, and it started when the fabric samples were dipped for 1 min in the solution containing all the starting materials. The treated and untreated fabric samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and EDS. The cotton fabrics coated with ZnO nanostructures presented an antibacterial efficiency towards Pseudomonas aeruginosa, a gram-negative bacteria, and Staphylococcus aureus (S. aureus), a gram-positive bacteria.

Currently the use of nanotechnology has been seeking to develop additives that have antimicrobial and low toxicity, enabling applications in various industrial sectors, in particular the paint industry. Inks with antimicrobial properties enable greater security to the user, eliminating pathogens that can cause disease when in contact with humans and animals. Thus, the zinc oxide nanoparticles have attracted a great scientific and technological interest as inorganic antimicrobial agent due to its oligodynamic effect. This work aims to study the effect oligodynamic zinc oxide nanoparticles in antimicrobial properties of acrylic paints. The acrylic paints were developed with various concentrations of zinc oxide nanoparticles, and were subsequently conducted microbiological characterization of death curve and agar diffusion. To evaluation the physico-chemical properties were used the techniques differential scanning calorimetry (DSC); Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results demonstrate that there was a reduction in the high antimicrobial activity of paints containing zinc oxide nanoparticles as compared to standard paint. Even with the addition of zinc oxide nanoparticles did not change the microstructure and chemical properties of acrylic coatings.