Sorption and desorption of the herbicide alachlor on humic acid fractions from two vermicomposts.

The present study focuses on the analysis of two vermicomposts, that have been used as alternative sources of restitution of soil organic matter, as well as sources of nutrient replacements. For this purpose, two samples of vermicomposts from different Brazilian regions (S?o Carlos-SP and Londrina-PR) were characterized according to their humic acid content. Both samples had a pH value near 7.0, and the humic acids present showed high cationic exchange capacities and low values for the C/N ratios. The infrared spectra showed bands that suggested the presence of aliphatic and aromatic components bound to phenolic, carboxylic and amide groups. The effect of vermicompost added to soil on the application of alachlor was evaluated. Alachlor sorption, Freundlich isotherms and alachlor desorption curves in the soil matrix and the vermicompost/soil mixture matrix were determined.     

Artificial lakes as a climate change adaptation strategy in drylands: evaluating the trade-off on non-target ecosystem services

Drylands are very susceptible to the effects of climate change due to water stress. One possible climate change adaptation measure is the construction of lakes to increase water availability for drinking and irrigation (food production) and decrease fire risk. These lakes can also increase local biodiversity and human well-being. However, other non-target services such as carbon (C) storage, water purification, and sediment retention might also change. Our main aim was to evaluate the trade-offs on non-targeted ecosystem services due to lakes construction in drylands. This was done using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) modeling tools, comparing a Mediterranean area located in southwest (SW) Europe, with and without artificial lakes. Results showed that the construction of artificial lakes caused an increase of 9.4% in C storage. However, the consequent increase in agricultural area decreased water purification and sediment retention services. This could diminish the life span of the lakes changing the initial beneficial cost-benefit analysis on lakes as adaptation measures to climate change. As a global measure for mitigation and adaptation to climate change strategy, we consider lake construction in drylands to be positive since it can store C in sediments and reduces the vulnerability to water scarcity. However, as a general recommendation and when built to support or increase agriculture in semi-arid landscapes, we consider that lakes should be complemented with additional measures to reduce soil erosion and nutrient leaching such as (i) locate agricultural areas outside the lakes water basin, (ii) afforestation surrounding the lakes, and (iii) adopt the best local agriculture practices to prevent and control soil erosion and nutrient leaching.     

The impact of fragmentation and density regulation on forest succession in the Atlantic rain forest

The Atlantic Rain Forest, an important biodiversity hot spot, has faced severe habitat loss since the last century which has resulted in a highly fragmented landscape with a large number of small forest patches (<100 ha). For conservation planning it is essential to understand how current and future forest regeneration depends on ecological processes, fragment size and the connection to the regional seed pool. We have investigated the following questions by applying the forest growth simulation model FORMIND to the situation of the Atlantic Forest in the state of São Paulo, SE Brazil: (1) which set of parameters describing the local regeneration and level of density regulation can reproduce the biomass distribution and stem density of an old growth forest in a reserve? (2) Which additional processes apart from those describing the dynamics of an old growth forest, drive forest succession of small isolated fragments? (3) Which role does external seed input play during succession? Therefore, more than 300 tree species have been classified into nine plant functional types (PFTs), which are characterized by maximum potential height and shade tolerance. We differentiate between two seed dispersal modes: (i) local dispersal, i.e. all seedlings originated from fertile trees within the simulated area and (ii) external seed rain. Local seed dispersal has been parameterized following the pattern oriented approach, using biomass estimates of old growth forest. We have found that moderate density regulation is essential to achieve coexistence for a broad range of regeneration parameters. Considering the expected uncertainty and variability in the regeneration processes it is important that the forest dynamics are robust to variations in the regeneration parameters. Furthermore, edge effects such as increased mortality at the border and external seed rain have been necessary to reproduce the patterns for small isolated fragments. Overall, simulated biomass is much lower in the fragments compared to the continuous forest, whereas shade tolerant species are affected most strongly by fragmentation. Our simulations can supplement empirical studies by extrapolating local knowledge on edge effects of fragments to larger temporal and spatial scales. In particular our results show the importance of external seed rain and therefore highlight the importance of structural connectivity between regenerating fragments and mature forest stands.     

Acute toxicity of sugarcane vinasse to aquatic organisms before and after pH adjustment

The purpose of this study was to investigate the toxicity of vinasse to cladocerans and fish before and after pH adjustment using an acute toxicity test. Linear and quadratic regression models were adjusted to demonstrate the concentration–response relationship between vinasse and the endpoints evaluated. The median lethal concentrations (LC_50–48h) of vinasse before pH adjustment for Ceriodaphnia dubia and Daphnia magna were 0.67% and 0.80% respectively, and the median lethal concentrations (LC_50–96h) for Danio rerio was 2.62%. After pH adjustment, the values increased for all organisms, demonstrating a decrease in toxicity. This study reported marked toxicity for vinasse to aquatic organisms with toxicity reduction after pH adjustment.     

Evaluation of the biomethane potential of solid fish waste

Manufacturing processes in fish canning industries generate a considerable amount of solid waste that can be digested anaerobically. The aim of this research was to study the biochemical methane potential of different solid fish waste. For tuna, sardine and needle fish waste, around 0.47g COD-CH(4)/g COD(added) was obtained in batch experiments with 1%TS; whereas for mackerel waste, the methane production attained 0.59g COD-CH(4)/g COD(added). The increase in the waste/inoculum ratio, from 1.1-1.3 to 2.8-3.3g VS(waste)/g VS(inoculum), led to overload due to VFA and LCFA accumulation. Afterward, co-digestion assays of fish waste with gorse were undertaken but the biochemical methane potential did not improve.     

Aerosols concentration in the Candiota area applying different gravimetric methods of sampling and numeric modelling

The main purpose of the present work is to study the concentration of atmospheric particles in the Candiota region, in the state of Rio Grande do Sul, where the Presidente Médici coal power plant is located. Aerosol samples were collected at the studied locations between December 2000 and December 2001 during 24 h periods at 15 day intervals using HV PM10 and dichotomous samplers. Then, the values obtained with the ISCST (Industrial Source Complex Term) model, with the HV PM10 sampler at all studied stations, and with the dichotomous sampler at the 8 de Agosto station were compared with each other. The results show that the values for the model had been underestimated in relation to the HV PM10 data for the studied stations, but agreed with the values obtained with the dichotomous sampler.     

The influence of urbanization on natural radiation levels in anomalous areas

This paper verifies the effects of urbanization on the original levels of environmental gamma radiation in an anomalous area. The fieldwork was done in the city of Guarapari, on the seacoast of the state of Espírito Santo, Brazil. This place was chosen because the whole region is naturally rich in monazite sand, which contains thorium and uranium. A similar study was also carried out in the 1960s. The measurements were done using an inorganic NaI scintillometer detector with Cu+Pb filters coupled to a scaler. The methodology of measurements used was similar to the one applied in the fieldwork carried out in the 1960s. In addition, a simulation was performed in the laboratory, to determine the attenuation of the materials used in the urbanization of the region. The results of this work clearly show that there was a reduction in the levels of external radiation in the streets and squares of Guarapari. It was concluded that the reduction was due to attenuation by the materials used in the urbanization.     

Cancer and occupational exposure to pesticides: a bibliometric study of the past 10 years

Environmental Science and Pollution Research - Occupational exposure to pesticides has been identified as a major trigger of the development of cancer. Pesticides can cause intoxication in the...