Iron and sulfur geochemistry in semi-arid mangrove soils (Ceará, Brazil) in relation to seasonal changes and shrimp farming effluents

Iron and sulfur are key elements in the biogeochemistry of estuarine soils, in which Fe and sulfate reduction (SR) pathways are important for organic matter decomposition. In the semi-arid coast of NE Brazil, mangroves are characterized by large seasonal variations in weather and the presence of numerous shrimp farms. The objective was to determine the impacts of shrimp farm effluents on iron and sulfur geochemistry in mangrove soils under the semi-arid climate of NE Brazil. A seasonal study was made of two mangrove forest soils (SF, a mangrove forest that directly receives wastewater from shrimp ponds and CS, a control site). Pyrite Fe, oxyhydroxides Fe, acid volatile sulfide, degree of pyritization (DOP), pH, Eh, total organic carbon (TOC) and total S were determined. There was a clear decrease in pyritic Fe and DOP in the SF soils, which may be related to the anaerobic oxidation of pyrite coupled with nitrate reduction, or to the dominance of denitrification over SR. Lower TOC contents in the SF site suggest that below ground decomposition increased in response to eutrophication. The seasonal variations led to important changes in the semi-arid mangrove soils. During the dry period, both soils experienced oxidizing conditions with remarkable loss of reduced and oxidized forms of Fe, which may have important environmental implications as Fe is biolimiting for marine primary production. The data show that both factors (seasonal weather variations and shrimp effluents) play important roles in the geochemical processes that occur in these soils and, thus, may affect their functioning and maintenance.     

A review of regulatory decisions for environmental protection: part II - the case-study of contaminated land management in Portugal

This paper provides a case-study analysis of the challenges in the implementation of national soil policies, which was developed by the authors in Part I of the review of regulatory decisions for environmental protection [Rodrigues SM, Pereira ME, Ferreira da Silva E, Hursthouse A, Duarte AC. A review of regulatory decisions for environmental management: Part I-challenges in the implementation of national soil policies. Environ Int 2009. doi:10.1016/j.envint.2008.08.007]. The Portuguese case was selected as a case-study since specific regulatory decisions for contaminated land management are still in the early stages of development. Given the gap between the situation at the EU level and the state of Portuguese soil policy development, it is of merit to consider national contaminated land policy regimes already in place within the EU and to see if these provide a suitable basis to define the main challenges and research needs for the implementation of a Portuguese contaminated land management strategy. A framework combining the D-P-S-I-R (drivers-pressures-sources-impacts-responses) structure of policy evaluation with the Source-Pathway-Receptor approach to health risk assessment is proposed to derive an effective regulatory framework for managing contaminated land in Portugal, using available information and only to develop new data and research where knowledge gaps exist. Funding site clean-up and assigning liability were identified as relevant factors currently hampering site remediation. Most relevant research needs for the development of contaminated land management practices in Portugal are those associated to the definition of a risk assessment framework and setting guidelines for the evaluation of risks posed to both humans and ecosystems. Other relevant and innovative features are the integration of soil function analysis into site investigations and the definition of a framework that combines risk assessment with soil function analysis. The analysis of the Portuguese case also provides insight into the discussions needed for the effective development of regulatory decisions for contaminated land management in countries with no history of implementing specific soil policies.     

Social acceptance of wind and solar power in the Brazilian electricity system

Renewable energy is often associated with the production of clean electricity and free of significant adverse impacts. However, several studies have been highlighting the importance of the assessment of social impacts of these technologies, including not only the benefits but also the potential negative aspects most frequently affecting local population. The energy matrix in Brazil is already built up on a renewable system largely supported on hydropower but other technologies with special emphasis on wind power start to have a major role, with a strong growth forecasted for this sector in the coming years. This article discusses the integration of solar and wind power in the Brazilian electricity system focusing on the social awareness and acceptance for the population living in high potential regions. For this, a questionnaire was proposed with the aim of evaluating the level of knowledge of wind and solar power, their social acceptance and perceptions towards cost, local development and environmental impacts. The questionnaire was implemented in an academic institution in the State of Rio Grande do Norte (RN) including students and professors as key actors for the present and future energy policy decision making. The implementation process and the obtained results are described allowing to conclude on the high level of acceptance of solar and wind power in the country and the region, with low evidence of not in my backyard syndrome.     

Efficiency of physicochemical and biological treatments of vinasse and their influence on indigenous microbiota for disposal into the environment

Molasses-based distilleries are one of the most polluting industries generating large volumes of high strength wastewater called vinasse. Different processes covering anaerobic, aerobic as well as physicochemical methods have been employed to treat this effluent. This study evaluated the microbial communities present in the vinasse during different stages of its treatment by traditional and molecular methods. The analysis of the efficiency of each treatment was performed by physicochemical parameters and toxicity analysis. The treatment of vinasse was performed in the following steps: high flow fermentation; filtration; chemical flakes; low-flow fermentation; filtration; and neutralization. The physicochemical analysis in different stages of the vinasse treatment demonstrated that phases of treatment influenced the performance of the evaluated parameters. Among the 37 parameters, 9 were within the limits established by the Commission for Environmental Policy of Minas Gerais, Brazil (COPAM), especially BOD (96.7% of pollution reduction), suspended solids (99.9%), pH, copper (88%), iron (92.9%), and manganese (88%). Some parameters, even after treatment, did not fit the maximum allowed by legislation. The microbial population decreased reaching 3 log CFU/ml present in the steps of the flakes chemical and disinfection treatment of vinasse. Lactobacillus brevis and Pichia kudriavzevii were present in all stages of the treatments, showing that these microorganisms were resistant and demonstrated that they might be important in the treatment of vinasse. The vinasse showed a significant reduction of pollution load after the disinfection treatment however still should not be discarded into water bodies because the high values of tannins and sediment solids, but suggest the use of the effluent in the cooling coil during the distillation process of the beverage.     

The environmental attitude of the urban population living in Macapá City,Brazilian Amazon region

Environment, Development and Sustainability - The human pressure on nature makes it imperative understanding how environmental issues can influence the world view of society. The aim of the current...     

Toxicological responses in Laeonereis acuta (annelida, polychaeta) after arsenic exposure

Several environmental pollutants, including metals, can induce oxidative stress. So, the objective of this study was to evaluate the effects of arsenic (As(III), as As(2)O(3)) on the antioxidant responses in the polychaete Laeonereis acuta. Worms were exposed to two environmentally relevant concentrations of As, including the highest previously allowed by Brazilian legislation (50 microg As/l). A control group was kept in saline water (10 per thousand) without added metal. It was observed that: (1) a peak concentration of lipid peroxide was registered after 2 days of exposure to 50 microg As/l (61+/-3.2 nmol CHP/g wet weight) compared to the control group (43+/-4.5 nmol CHP/g wet weight), together with a lowering of the activity of the antioxidant enzyme catalase (-47 and -48%, at 50 or 500 microg As/l respectively) and a higher superoxide dismutase activity (+305% at 50 microg As/l with respect to the control group); (2) a lower conjugation capacity through glutathione-S-transferase activity was observed after 7 days of exposure to 50 microg As/l (-48% compared to the control group); (3) a significant increase in As concentration was verified after 1 week of exposure to both As concentrations (50 and 500 microg/l); (4) worms exposed to As showed a limited accumulation of related methylated As species and the levels of non-toxic As species like arsenobetaine (AsB) and arsenocholine (AsC) remained unchanged during the exposure period when compared with the controls. Overall, it can be concluded that As interfered in the antioxidant defense system of L. acuta, even at low concentrations (50 microg/l) that Brazilian legislation previously considered safe. The fact that worms exposed to As showed high levels of methylated As species indicates the methylation capability of L. acuta, although the high levels of inorganic As suggest that not all the administered As(III) (as As(2)O(3)) is completely removed or biotransformed after 7 days of exposure.     

Evaluation of the toxicity of two soils from Jales Mine (Portugal) using aquatic bioassays

Soil contamination can be one path for streams and groundwater contamination. As a complement of chemical analysis and total contaminants determination, bioassays can provide information on the bioavailable fraction of chemical compounds, focusing on the retention and habitat function of soils. In this study the evaluation of the toxicity of two soils from the abandoned Jales Mine (Portugal) regarded both functions. The buffer capacity of soils was tested with bioassays carried out using the cladoceran Daphnia magna and the marine bacteria Vibrio fischeri. The habitat function of soils was evaluated with the reproduction bioassay with the collembolan Folsomia candida. The Microtox solid-phase test was performed with V. fischeri using soil as test medium, and soil elutriates were extracted to perform the Microtox basic test, and an immobilization and reproduction bioassay with D. magna. The marine bacteria showed high sensitivity to the soil with low heavy metal content (JNC soil) and to JNC soil elutriates, while the soil with highest heavy metal content (JC soil) or soil elutriates exposure did not cause any toxic effect. In the bioassays with D. magna, organisms showed sensitivity to JNC and also to JC soil elutriates. Both mobilization and reproduction features were inhibited. The bioassay with F. candida did not reflect any influence of the contaminants on their reproduction. Although JNC soil presented lower heavy metal contents, elutriates showed different patterns of contamination when compared to JC soil and elutriates, which indicates different retention and buffer capacities between soils. Results obtained in this study underlined the sensitivity and importance of soil elutriate bioassays with aquatic organisms in the evaluation strategy in soil ERA processes.     

EFFECTS OF SPATIAL ORIENTATION OF MULTIPLE PLATE ARTIFICIAL SUBSTRATES ON INVERTEBRATE COLONIZATION1

ABSTRACT: Jumbo multiple plate samplers were suspended in a river at 0.3 and 1 m depth in one of three orientations: interplate spaces closed to downwelling light and open to flow, open to light and flow, or open to light and closed to flow. Mean numbers of colonizing taxa and individuals were not significantly different among orientations after eight weeks of submergence. All variables tested decreased significantly with depth. Mean number of taxa, number of individuals (1 m only), and insect diversity decreased between samplings at four and eight weeks for samplers that were closed to light and open to flow. All orientations, depths, and durations had one-half to two-thirds of the total taxa. Colonization was affected by location in the river and position on sampler suspension equipment. The results indicate lack of orientation effects on colonization or high variability that obscured such effects. The sampler suspension equipment possibly increased among-sampler variability by forming artificial snag habitats, and interplate light and flow conditions at different orientations may not have been sufficiently distinct to elicit different biological responses. Individual samplers provided diverse microhabitats regardless of orientation, but it would be prudent to include orientation among the variables considered in use of multiple plate samplers.     

Application and sensitivity testing of a eutrophication assessment method on coastal systems in the United States and European Union

The Assessment of Estuarine Trophic Status (ASSETS) screening model has been extended to allow its application to both estuarine and coastal systems. The model, which combines elements of pressure, state and response, was tested on four systems: Maryland Coastal Bays and Long Island Sound in the United States and The Firth of Clyde (Scotland) and Tagus Estuary (Portugal) in the European Union. The overall scores were: Maryland Coastal Bays: Bad; Firth of Clyde: Poor; Tagus Estuary: Good. Long Island Sound was modelled along a timeline, using 1991 data (score: Bad) and 2002 data (score: Moderate). The improvement registered for Long Island Sound is a consequence of the reduction in nutrient loading, and the ASSETS score changed accordingly. The two main areas where developments are needed are (a) In the definition of type-specific ranges for eutrophication parameters, due to the recognition that natural or pristine conditions may vary widely, and the use of a uniform set of thresholds artificially penalizes some systems and potentially leads to misclassification; (b) In the definition and quantification of measures which will result in an improved state through a change in pressures, as well as in the definition of appropriate metrics through which response may be assessed. One possibility is the use of detailed research models where different response scenarios potentially produce changes in pressure and state. These outputs may be used to drive screening models and analyze the suitability of candidate metrics for evaluating management options.