Genetic toxicity in surface water from Guaíba Hydrographic Region under the influence of industrial, urban and agricultural sewage in the Drosophila wing-spot test

Mutagenic and recombinagenic activity of surface waters in the Guaíba Hydrographic Region (RS, Brazil) was investigated using the SMART in Drosophila melanogaster. Two positive results in Caí River (September 2000 and August 2001) and in Taquari River (August 2001 and February 2002)--linked to direct recombinagenic toxicants were observed. In Jacuí samples, an indirect mutagenic and recombinagenic action was detected in a September 2000 collection and a direct recombinational activity was observed in February 2002. Also in February 2002--samples from Dilúvio Brook and Guaíba Lake (GPC) were able to induce wing spots by mitotic recombinagenesis. The former sampling site showed toxicants to have a direct action, and the latter an increment in mitotic recombination that depended on metabolic action. The SMART wing test shows that all positive responses were mainly related to homologous mitotic recombination.     

Assessing ecological function in the context of species recovery

Species interactions matter to conservation. Setting an ambitious recovery target for a species requires considering the size, density, and demographic structure of its populations such that they fulfill the interactions, roles, and functions of the species in the ecosystems in which they are embedded. A recently proposed framework for an International Union for Conservation of Nature Green List of Species formalizes this requirement by defining a fully recovered species in terms of representation, viability, and functionality. Defining and quantifying ecological function from the viewpoint of species recovery is challenging in concept and application, but also an opportunity to insert ecological theory into conservation practice. We propose 2 complementary approaches to assessing a species’ ecological functions: confirmation (listing interactions of the species, identifying ecological processes and other species involved in these interactions, and quantifying the extent to which the species contributes to the identified ecological process) and elimination (inferring functionality by ruling out symptoms of reduced functionality, analogous to the red-list approach that focuses on symptoms of reduced viability). Despite the challenges, incorporation of functionality into species recovery planning is possible in most cases and it is essential to a conservation vision that goes beyond preventing extinctions and aims to restore a species to levels beyond what is required for its viability. This vision focuses on conservation and recovery at the species level and sees species as embedded in ecosystems, influencing and being influenced by the processes in those ecosystems. Thus, it connects and integrates conservation at the species and ecosystem levels.     

Exposure to Selected Heavy Metals Through Water Ingestion in an Area Under the Influence of Tanneries

This study evaluated the potential toxicological risk posed to human health due to the exposure to heavy metals by water ingestion in an area affected by tanneries – the Cadeia-Feitoria hydrographic basin (Brazil). River water was collected at 10 sites, every 3 months, from July 1999 to April 2000. After acid digestion, total metal concentration was determined by inductively coupled plasma optical emission spectrometry (Cd, Cu, Cr, Ni, Zn), flame atomic absorption (Al, Fe, Pb, Mn), or cold vapor atomic absorption spectrometry (Hg). Cr(VI) was complexed with diphenyl-carbazide and detected by UV–vis spectrometry. In order to quantify the risk of exposure, the risk assessment methodology employed by the Environmental Protection Agency of the United States was applied at a screening level. The assumed scenarios included extreme exposure patterns (ingestion of untreated water, conversion of Cr(III) to Cr(VI), temporal peaks of pollution). Fe, Al, Cd, Hg, and Pb were not included in the risk analysis, since they showed a low toxicity potential or were undetected in the samples. The selected metals presented Hazard Quotients < 1, in the following order of increasing risk: Cu < Cr(III) < Zn < Ni < Mn < Cr(VI). Hazard indexes, representing the additive effect of contaminants, were also low in the basin (< 1), but comparatively increased in the lower reach of Feitoria and Cadeia Rivers. Although noncarcinogenic risk levels did not suggest possible adverse toxicological effects to the human population, a considerable deviation from background conditions was observed downstream the area where tanneries are mainly located.     

Alterations in some renal parameters of rats induced by aqueous soil extracts

Soil ingestion can be an important route of exposure to contaminants present in the environment. This study examined the effects of exposure to contaminants in aqueous soil extracts from an industrial urban settlement in renal biochemical parameters of treated rats. Male Wistar rats were gavaged with an aqueous soil extract, from the municipality of Rio Grande, Southern Brazil. After exposure, plasma and urine concentrations and plasma protein were assessed compared to rats treated with aqueous soil from relatively unpolluted site (control soil). There was increase in plasma creatinine and total protein in urine, and a decreased glomerular filtration rate in treated rats compared to control. It is possible that Cd, Cr, As, Cu, Pb, Zn, and Ni analyzed in the soil samples and unidentified components may have provoked the observed changes in renal biochemistry of the exposed rat. This may suggest that exposure to contaminated soils can cause damage to the viscera in mammals and it is of public health importance.     

Biological impacts of ocean acidification: a postgraduate perspective on research priorities

Research into the effects of ocean acidification (OA) on marine organisms has greatly increased during the past decade, as realization of the potential dramatic impacts has grown. Studies have revealed the multifarious responses of organisms to OA conditions, indicating a high level of intra- and interspecific variation in species’ ability to accommodate these alterations. If we are to provide policy makers with sound, scientific input regarding the expected consequences of OA, we need a broader understanding of these predicted changes. As a group of 20 multi-disciplinary postgraduate students from around the globe, with a study focus on OA, we are a strong representation of ‘next generation’ scientists in this field. In this unique cumulative paper, we review knowledge gaps in terms of assessing the biological impacts of OA, outlining directions for future research.     

DNA damage in oral epithelial cells of individuals chronically exposed to indoor radon (<Superscript>222</Superscript>Rn) in a hydrothermal area

Hydrothermal areas are potentially hazardous to humans as volcanic gases such as radon (²²²Rn) are continuously released from soil diffuse degassing. Exposure to radon is estimated to be the second leading cause of lung cancer, but little is known about radon health-associated risks in hydrothermal regions. This cross-sectional study was designed to evaluate the DNA damage in the buccal epithelial cells of individuals chronically exposed to indoor radon in a volcanic area (Furnas volcano, Azores, Portugal) with a hydrothermal system. Buccal epithelial cells were collected from 33 individuals inhabiting the hydrothermal area (Ribeira Quente village) and from 49 individuals inhabiting a non-hydrothermal area (Ponta Delgada city). Indoor radon was measured with Ramon 2.2 detectors. Chromosome damage was measured by micronucleus cytome assay, and RAPD-PCR was used as a complementary tool to evaluate DNA damage, using three 10-mer primers (D11, F1 and F12). Indoor radon concentration correlated positively with the frequency of micronucleated cells (r _s = 0.325, p = 0.003). Exposure to radon is a risk factor for the occurrence micronucleated cells in the inhabitants of the hydrothermal area (RR = 1.71; 95% CI, 1.2–2.4; p = 0.003). One RAPD-PCR primer (F12) produced differences in the banding pattern, a fact that can indicate its potential for detecting radon-induced specific genomic alterations. The observed association between chronic exposure to indoor radon and the occurrence of chromosome damage in human oral epithelial cells evidences the usefulness of biological surveillance to assess mutations involved in pre-carcinogenesis in hydrothermal areas, reinforcing the need for further studies with human populations living in these areas.     

Analysis of the global warming dynamics from temperature time series

Global warming is the observed increase of the average temperature of the Earth. The primary cause of this phenomenon is the release of the greenhouse gases by burning of fossil fuels, land cleaning, agriculture, among others, leading to the increase of the so-called greenhouse effect. An approach to deal with this important problem is the time series analysis. In this regard, different techniques can be applied to evaluate the global warming dynamics. This kind of analysis allows one to make better predictions increasing our comprehension of the phenomenon. This article applies nonlinear tools to analyze temperature time series establishing state space reconstruction and prediction. Since noise contamination is unavoidable in data acquisition, it is important to employ robust techniques. The method of delay coordinates is employed for state space reconstruction and delay parameters are evaluated using the method of average mutual information and the method of false nearest neighbors. Afterwards, the simple nonlinear prediction method is employed to estimate temperatures of the future. Temperature time series from different places of the planet are used. Initially, the approach is verified considering known parts of the time series and afterwards, results are extrapolated for future values estimating temperature until 2028. Results show that these techniques are interesting to estimate temperature time history, presenting coherent estimations.     

Using stochastic volatility models to analyse weekly ozone averages in Mexico City

In this paper we make use of some stochastic volatility models to analyse the behaviour of a weekly ozone average measurements series. The models considered here have been used previously in problems related to financial time series. Two models are considered and their parameters are estimated using a Bayesian approach based on Markov chain Monte Carlo (MCMC) methods. Both models are applied to the data provided by the monitoring network of the Metropolitan Area of Mexico City. The selection of the best model for that specific data set is performed using the Deviance Information Criterion and the Conditional Predictive Ordinate method.     

Cement industry: sustainability, challenges and perspectives

Cement-based materials, such as concrete and mortars, are used in extremely large amounts. For instance, in 2009 concrete production was superior to 10 billion tons. Cement plays an important role in terms of economic and social relevance since it is fundamental to build and improve infrastructure. On the other hand, this industry is also a heavy polluter. Cement production releases 5–6% of all carbon dioxide generated by human activities, accounting for about 4% of global warming. It can release huge amounts of persistent organic pollutants, such as dioxins and heavy metals and particles. Energy consumption is also considerable. Cement production use approximately 0.6% of all energy produced in the United States. On the other hand, the chemistry underlying cement production and its applications can be very helpful to overcome these environmental issues. In terms of manufacture, there are many alternative materials that can be used to minimize carbon dioxide production and reduce energy consumption, such as calcium sulfoaluminates and β-Ca₂SiO₄—rich cements. Using residues from other industrial sectors can also improve the sustainability of cement industry. Under adequate conditions, waste materials such as tyres, oils, municipal solid waste and solvents can be used as supplementary fuel in cement plants. Concrete can be used for encapsulation of waste materials such as tyres, plastics and glasses. In this review, we discuss some aspects of the cement industry associated with environmental science. Other issues such as economic aspects, the chemistry of cement manufacture and its properties are also presented. Special attention is given to the role that cement chemistry can play in terms of sustainability. The most relevant aspects are outlined, such as the use of alternative materials, new possibilities and also the recycling of materials. It is also argued that an important aspect is the role of research and development necessary to improve cement sustainability.