Degradability and Sediment Sorption of an Alcohol Polyglycol Ether Surfactant Putatively Useful for the Control of Red Swamp Crayfish in Rice Fields

This work reports studies of the degradation rates of a fattyalcohol polyglycol ether non-ionic surfactant, Genapol OXD-080, putatively useful for the control of red swamp crayfish (Procambarus clarkii Girard) in rice fields under laboratory and field conditions. The influence of temperature,sediment site specificity and sorption were taken into account.The degradation kinetics of the surfactant depends on the experimental conditions: type of inocula and temperature. Thedistribution of this chemical in aquatic systems was also examined. Genapol OXD-080 was removed into the sedimentsreadily after application, and sorption was considered the majorpath of removal from the water phase. Data suggest that furtherstudies are required regarding the effects of Genapol OXD-080 in aquatic organisms resident in rice fields, in parallelwith the development of technologies related with the use ofsurfactants to control P. clarkii populations.     

Biochemical biomarkers in Nile tilapia (Oreochromis niloticus) after short-term exposure to diesel oil, pure biodiesel and biodiesel blends

Fossil fuels such as diesel are being gradually replaced by biodiesel, a renewable energy source, cheaper and less polluting. However, little is known about the toxic effects of this new energy source on aquatic organisms. Thus, we evaluated biochemical biomarkers related to oxidative stress in Nile tilapia (Oreochromis niloticus) after two and seven exposure days to diesel and pure biodiesel (B100) and blends B5 and B20 at concentrations of 0.01 and 0.1 mL L⁻¹. The hepatic ethoxyresorufin-O-deethylase activity was highly induced in all groups, except for those animals exposed to B100. There was an increase in lipid peroxidation in liver and gills in the group exposed to the higher concentration of B5. All treatments caused a significant increase in the levels of 1-hydroxypyrene excreted in the bile after 2 and 7 d, except for those fish exposed to B100. The hepatic glutathione-S-transferase increased after 7 d in animals exposed to the higher concentration of diesel and in the gill of fish exposed to the higher concentration of pure diesel and B5, but decreased for the two tested concentrations of B100. Superoxide dismutase, catalase and glutathione peroxidase also presented significant changes according to the treatments for all groups, including B100. Biodiesel B20 in the conditions tested had fewer adverse effects than diesel and B5 for the Nile tilapia, and can be suggested as a less harmful fuel in substitution to diesel. However, even B100 could activate biochemical responses in fish, at the experimental conditions tested, indicating that this fuel can also represent a risk to the aquatic biota.     

Green marketing mix: A case study of Brazilian retail enterprises

The challenges posed by the limited availability of resources means that retail operations and methods must be revised and redesigned. Against the current backdrop of changes, companies are seeking to innovate the way in which they market their wares. Within this context, this article discusses the “green marketing mix” from the perspective of Brazilian retail enterprises. In addition, the study described in this article sought to identify and highlight the elements that should be considered when defining strategically each variable within the green retail marketing mix. As part of this work, a case study was carried out on two Brazilian retail companies. The case analysis revealed that despite defining themselves as “green,” when their retail marketing mix was analyzed, the companies presented differing degrees of sustainability. Furthermore, expanding the theoretical framework for the green retail marketing mix is a crucial issue in the services sector, and it has significant, practical repercussions.     

Report: New guidelines for characterization of municipal solid waste: the Portuguese case

This report proposes a new set of guidelines for the characterization of municipal solid waste. It is based on an analysis of reference methodologies, used internationally, and a case study of Valorsul (a company that handles recovery and treatment of solid waste in the North Lisbon Metropolitan Area). In particular, the suggested guidelines present a new definition of the waste to be analysed, change the sampling unit and establish statistical standards for the results obtained. In these new guidelines, the sampling level is the waste collection vehicle and contamination and moisture are taken into consideration. Finally, focus is on the quality of the resulting data, which is essential for comparability of data between countries. These new guidelines may also be applicable outside Portugal because the methodology includes, besides municipal mixed waste, separately collected fractions of municipal waste. They are a response to the need for information concerning Portugal (e.g. Eurostat or OECD inquiries) and follow European Union municipal solid waste management policies (e.g. packaging waste recovery and recycling targets and the reduction of biodegradable waste going to landfill).     

Dibenzothiophene oxidation by horseradish peroxidase in organic media: effect of the DBT:H2O2 molar ratio and H2O2 addition mode

Its is well known that in the biodesulfurization (BDS) process the low water solubility of sulfur compounds hinders its transference from the oil phase to the cells being the rate-limiting step in the metabolism of dibenzothiophenes (DBT). Thus sulfur compounds derivatives with high water solubility could be more easily transported increasing the BDS efficiency. The present work performed a stepwise evaluation of the enzymatic oxidation of DBT by horseradish peroxidase (HRP). Reactions were carried out in monophasic organic media containing 25% (v/v) acetonitrile. The following parameters were evaluated: DBT:H2O2 molar ratio (1:1-1:20); H2O2 addition mode (single or stepwise); pH (6.0-8.0) and temperature (37-50 degrees C). Best results were observed in a reaction medium at pH 8.0 presenting HRP 0.06IUml(-1), DBT 0.267mM, DBT:H2O2 molar ratio of 1:20 (stepwise hydrogen peroxide addition) and incubated at 45 degrees C for 60min. Under these conditions 60% of DBT was converted into dibenzothiophene sulfoxide (12%) and dibenzothiophene sulfone (46%). The DBT oxidation rate observed in this work, of 5mmolmin(-1)g(-1) of HRP, was 250-fold higher than the BDS rate, 20mumolmin(-1)g(-1) of catalyst. As such a combined enzyme-microbial desulfurization process could be envisaged. Products were determined by HPLC RP C-18.     

Accurate DTM generation in sand beaches using mobile mapping

A Mobile Mapping System (MMS) is composed by a set of sensors placed on a mobile platform whose main objective is to obtain attitude and position over time of a referential in the platform together with the image of the objects surrounding the platform. The acquired data allows to obtain georeferenced positions of object points captured by the object sensors. This paper describes a methodology to automatically extract accurate Digital Terrain Models (DTM) of sand beach areas using a Terrestrial Mobile Mapping System (TMMS). The main goal of the presented TMMS is to obtain accurate 3D models of sand beaches. A very important consequence of this will be the abbility to track spatial and temporal changes in coastal geomorphology. The presented methodology has several advantages over more classical approaches: the overall cost, flexibility for regular surveys or at the most convenient epoch, such as after storms. Besides one of the major constraints in Mobile Mapping, that is poor GNSS (Global Navigation Satellite Systems) observation conditions, is usually not present in these areas. The TMMS uses two progressive colour video cameras and can work with any type of direct georeferencing system, which obvoiusly has impact in the final accuracy of the derived DTM. For the results herein reported, a dual frequency GNSS receiver and a low grade type of IMU (Inertial Measurement System) were used. The moving platform where the system was installed is a moto quad. The developed methodology for the DTM generation relies on an automatic choice of terrain points whose three-dimensional coordinates are calculated using a presented image matching technique. A cloud of points obtained in a nearly regular grid pattern is the base for the DTM. The proposed methodology was applied on a sector of the Vila Nova de Gaia Coast, in northern Portugal, and the results presented here show that it is possible with this methodology to produce DTMs with a precision of a few centimetres.     

Application of the Fenton’s process in a bubble column reactor for hydroquinone degradation

The aim of this study was to assess the degradation and mineralization of hydroquinone (HQ) by the Fenton’s process in a bubble column reactor (BCR). The effect of the main operating variables, namely, air flow rate, effluent volume, hydrogen peroxide (H₂O₂) concentration, catalyst (Fe²⁺) dose, initial pH, and temperature, were assessed. For all air flow rates tested, no concentration gradients along the column were noticed, evidencing that a good mixing was reached in the BCR. For the best conditions tested ([H₂O₂] = 500 mg/L, [Fe²⁺] = 45 mg/L, T = 24 °C, Q _air = 2.5 mL/min, pH = 3.0, and V = 5 L), complete HQ degradation was reached, with ~ 39% of total organic carbon (TOC) removal, and an efficiency of the oxidant use—η _H2O2—of 0.39 (ratio between TOC removed per H₂O₂ consumed normalized by the theoretical stoichiometric value); moreover, a non-toxic effluent was generated. Under these conditions, the intermediates and final oxidation compounds identified and quantified were a few carboxylic acids, namely, maleic, pyruvic, and oxalic. As a strategy to improve the TOC removal, a gradual dosage of the optimal H₂O₂ concentration was implemented, being obtained ~ 55% of mineralization (with complete HQ degradation). Finally, the matrix effect was evaluated, for which a real wastewater was spiked with 100 mg/L of HQ; no reduction in terms of HQ degradation and mineralization was observed compared to the solution in distilled water.     

Synthetic olive mill wastewater treatment by Fenton’s process in batch and continuous reactors operation

Degradation of total phenol (TPh) and organic matter, (expressed as total organic carbon TOC), of a simulated olive mill wastewater was evaluated by the Fenton oxidation process under batch and continuous mode conditions. A mixture of six phenolic acids usually found in these agro-industrial wastewaters was used for this purpose. The study focused on the optimization of key operational parameters of the Fenton process in a batch reactor, namely Fe²⁺ dosage, hydrogen peroxide concentration, pH, and reaction temperature. On the assessment of the process efficiency, > 99% of TPh and > 56% of TOC removal were attained when [Fe²⁺] = 100 ppm, [H₂O₂] = 2.0 g/L, T = 30 °C, and initial pH = 5.0, after 300 min of reaction. Under those operational conditions, experiments on a continuous stirred-tank reactor (CSTR) were performed for different space-time values (τ). TOC and TPh removals of 47.5 and 96.9%, respectively, were reached at steady-state (for τ = 120 min). High removal of COD (> 75%) and BOD₅ (> 70%) was achieved for both batch and CSTR optimum conditions; analysis of the BOD₅/COD ratio also revealed an increase in the effluent’s biodegradability. Despite the high removal of lumped parameters, the treated effluent did not met the Portuguese legal limits for direct discharge of wastewaters into water bodies, which indicates that coupled chemical-biological process may be the best solution for real olive mill wastewater treatment.     

Macroalgae mitigation potential for fish aquaculture effluents: an approach coupling nitrogen uptake and metabolic pathways using Ulva rigida and Enteromorpha clathrata

Aquaculture effluents are rich in nitrogen compounds that may enhance local primary productivity, leading to the development of algae blooms. The goal of this study was to assess the potential use of naturally occurring green macroalgae (Ulva and Enteromorpha) as bioremediators for nitrogen-rich effluents from a fish aquaculture plant, by evaluating their respective uptake dynamics under controlled conditions. Ulva and Enteromorpha were incubated separately in aquaculture effluent from a local pilot station. Algae tissue and water samples were collected periodically along 4 h. For each sample, nitrate, nitrite, and ammonia concentrations were quantified in the effluent, while internal algae reserve pools and nitrate reductase activity (NRA) were determined within the algae tissues. Both macroalgae absorbed all dissolved inorganic nitrogen compounds in less than 1 h, favoring ammonia over nitrate. Ulva stored nitrate temporarily as an internal reserve and only used it after ammonia availability decreased, whereas Enteromorpha stored and metabolized ammonia and nitrate simultaneously. These distinct dynamics of ammonia and nitrate uptake supported an increase in NRA during the experiment. This study supports the hypothesis that Ulva or Enteromorpha can be used as bioremediators in aquaculture effluents to mitigate excess of dissolved inorganic nitrogen.     

Use of multiple tools to assess the feeding preference of coastal dolphins

The feeding preferences of the coastal dolphins Pontoporia blainvillei and Sotalia guianensis in south-eastern Brazil (21o18′S–22o25′S) were assessed through the prey’s index of relative importance (IRI), total mercury concentration (Hg_tot), and stable isotopic (δ¹⁵N and δ¹³C) to compare their efficiency in the discrimination of prey contribution to the predators’ diet. The IRI was the best tool to describe the dolphins’ preference, while Hg_tot and δ¹⁵N seemed to be efficient as a trophic marker when the diet is made up of prey of varying sizes, as observed in S. guianensis. Both dolphins presented lighter δ¹⁵N than their prey species, which is an unusual pattern. However, as the sample size to isotope ratios analysis was small, especially to the dolphins, the results should be considered with caution, and further studies are necessary to corroborate these findings. The δ¹³C values characterized a typical coastal food chain, confirming the preferential area of these species.