Evaluation of optimal conditions for determination of low selenium content in shellfish samples collected at Todos os Santos Bay,Bahia, Brazil using HG-AFS

This work proposes a procedure for the determination of total selenium content in shellfish after digestion of samples in block using cold finger system and detection using atomic fluorescent spectrometry coupled hydride generation (HG AFS). The optimal conditions for HG such as effect and volume of prereduction KBr 10 % (m/v) (1.0 and 2.0 ml) and concentration of hydrochloric acid (3.0 and 6.0 mol L^?1) were evaluated. The best results were obtained using 3 mL of HCl (6 mol L^?1) and 1 mL of KBr 10 % (m/v), followed by 30 min of prereduction for the volume of 1 mL of the digested sample. The precision and accuracy were assessed by the analysis of the Certified Reference Material NIST 1566b. Under the optimized conditions, the detection and quantification limits were 6.06 and 21.21 μg kg^?1, respectively. The developed method was applied to samples of shellfish (oysters, clams, and mussels) collected at Todos os Santos Bay, Bahia, Brazil. Selenium concentrations ranged from 0.23?±?0.02 to 3.70?±?0.27 mg kg^?1 for Mytella guyanensis and Anomalocardia brasiliana, respectively. The developed method proved to be accurate, precise, cheap, fast, and could be used for monitoring Se in shellfish samples.     

Water quality of the Ribeirão Preto Stream, a watercourse under anthropogenic influence in the southeast of Brazil

It is known that Brazil still has a privileged position of water quantity and quality, but water use has not proceeded in a responsible manner and often results in impairment of quality. This study aims to evaluate limnological parameters, parasites and bacteria, and concentrations of heavy metals (Cd, Pb, Cu, Cr, Mn, Hg, and Zn) in surface water of Ribeirão Preto Stream. The Ribeirão Preto Stream is located in urban areas under anthropogenic influence. The results showed that the levels of dissolved oxygen values were lower than those established by the National Environmental Council (CONAMA Resolution No 357/2005). The reading of electrical conductivity showed values typical of impacted environments. The parasitological analysis revealed the presence of nematode larvae. The bacteriological analysis showed higher values for total coliform and Escherichia coli than those set by the Brazilian National Environment Council (CONAMA). The heavy metals Cd, Pb, Cu, Cr, Mn, Hg, and Zn showed concentrations in accordance with the guidelines established by CONAMA. The results provide data on the quality of these waters and showed the necessity to protect the watercourse from point sources of contamination, recommending their continued monitoring.     

A systematic indoor air quality audit approach for public buildings

Good indoor air quality (IAQ) in buildings provides a comfortable and healthy environment for the occupants to work, learn, study, etc. Therefore, it is important to ascertain the IAQ status in the buildings. This study is aimed to establish and demonstrate the comprehensive IAQ audit approach for public buildings, based on Portugal national laws. Four public buildings in Portugal are used to demonstrate the IAQ audit application. The systematic approach involves the measurement of physical parameters (temperature, relative humidity, and concentration of the suspended particulate matter), monitoring of the concentrations of selected chemical indicators [carbon dioxide (CO₂), carbon monoxide, formaldehyde, ozone, and total volatile organic compounds], and the measurements of biological indicators (bacteria and fungi). In addition, air exchange rates are measured by the concentration decay method using metabolic CO₂ as the tracer gas. The comprehensive audits indicated some situations of common IAQ problems in buildings, namely: (1) insufficient ventilation rate, (2) too high particle concentration; and (3) poor filtration effectiveness and hygienic conditions in most of the air handling units. Accordingly, a set of recommendations for the improvement of IAQ conditions were advised to the building owner/managers.     

Spatial distribution and enteroparasite contamination in peridomiciliar soil and water in the Apucaraninha Indigenous Land,southern Brazil

The prevalence and distribution of soil and water samples contaminated with enteroparasites of humans and animals with zoonotic potential (EHAZP) in Apucaraninha Indigenous Land (AIL), southern Brazil, was evaluated. An environmental survey was conducted to evaluate the presence of parasitic forms in peridomiciliary soil and associated variables. Soil samples were collected from 40/293 domiciles (10 domiciles per season), from November 2010 to June 2011, and evaluated by modified methods of Faust et al. and Lutz. Analyses of water from seven consumption sites were also performed. The overall prevalence of soil samples contaminated by EHAZP was 23.8 %. The most prevalent parasitic forms were cyst of Entamoeba spp. and eggs of Ascaris spp. The highest prevalence of contaminated soil samples was observed in winter (31 %). The probability map obtained with geostatistical analyses showed an average of 47 % soil contamination at a distance of approximately 140 m. The parasitological analysis of water did not detect Giardia spp. or Cryptosporidium spp. and showed that all collection points were within the standards of the Brazilian law. However, the microbiological analysis showed the presence of Escherichia coli in 6/7 sampled points. Despite the low level of contamination by EHAZP in peridomiciliar soil and the absence of pathogenic protozoa in water, the AIL soil and water (due to the presence of fecal coliforms) are potential sources of infection for the population, indicating the need for improvements in sanitation and water treatment, in addition periodic treatment of the population with antiparasitic.     

Horizon scanning for South African biodiversity: A need for social engagement as well as science

Ambio - A horizon scan was conducted to identify emerging and intensifying issues for biodiversity conservation in South Africa over the next 5–10 years. South African biodiversity...     

Utilization of UV‐A and UV‐C radiation in advanced oxidation processes with the intention of removing color and organic matter from the gross leachate of a stabilized sanitary landfill

The present work investigated color and biochemical oxygen demand (COD) removal from treated landfill leachate via advanced oxidative processes (AOPs) artificially emitted. The AOP H₂O₂/UV, TiO₂/UV, and photolysis were tested in two bench‐scale photoreactors: The first one with UV‐C lamp and the other with UV‐A lamp associated or not with coagulation / flocculation pretreatment. Crude leachate samples with pH ranging from 8 to 3 were used, and time varied in 30, 45, and 60 minutes. Experiments were performed in two stages: step 1 with a 20 mL volume from each sample and step 2 with repetition of the best results from the previous step, adopting the 150 mL volume. In step 1, the AOP applied in the crude leachate sample showed the best results, standing out H₂O₂/UV‐C with 30 minutes and TiO₂/UV‐A with 60 minutes. In step 2, H₂O₂/UV‐C had a 60% color removal and 25% COD reduction, while TiO₂/UV‐A had a 10% color removal and 20% COD reduction. Therefore, the H₂O₂/UV‐C process was the most efficient, because the complex characteristics of the effluent interfered in the TiO₂/UV‐A efficiency, but it is necessary to eliminate the process interferences. The use of artificial radiation is a viable alternative; however, it can be costly, being relevant in the associations between processes with artificial UV and solar UV, as the natural radiation becomes more attractive and allows the process operating costs reduction.     

Valorization of winery waste vs. the costs of not recycling

Wine production generates huge amounts of waste. Before the 1990s, the most economical option for waste removal was the payment of a disposal fee usually being of around 3000 Euros. However, in recent years the disposal fee and fines for unauthorized discharges have increased considerably, often reaching 30,000–40,000 Euros, and a prison sentence is sometimes also imposed. Some environmental friendly technologies have been proposed for the valorization of winery waste products. Fermentation of grape marc, trimming vine shoot or vinification lees has been reported to produce lactic acid, biosurfactants, xylitol, ethanol and other compounds. Furthermore, grape marc and seeds are rich in phenolic compounds, which have antioxidants properties, and vinasse contains tartaric acid that can be extracted and commercialized. Companies must therefore invest in new technologies to decrease the impact of agro-industrial residues on the environment and to establish new processes that will provide additional sources of income.     

Environmental monitoring model for a drainage basin obtained through spectral analysis of time series

The quality of results of an environmental monitoring plan is limited to the weakest component, which could be the analytical approach or sampling method. Considering both the possibilities and the fragility that sampling methods offer, this environmental monitoring study focused on the uncertainties caused by the time component. Four time series of nutrient concentration at two sampling points (PB1 and PB2) in the Ribeir?o Garcia basin in Blumenau, Brazil, which were significantly correlated to the spatial component, were considered with a 2-hour resolution to develop efficient sampling models. These models were based on the time at which there was the highest tendency toward adverse environmental effects. Fourier spectral analysis was used to evaluated the time series and resulted in two sampling models: (1) the SMCP (sampling model for critical period) that operated with 100% efficiency for registering the highest concentration of nutrients and was valid for 83% of the studied parameters; and (2) the SMGCP (sampling model for global critical period) that operated with 83 and 50% efficiency for PB1 and PB2, respectively.