Induced alkoxyresorufin-O-dealkylases in tilapias (Oreochromis niloticus) from Guandu river, Rio de Janeiro, Brazil

The activity of fish monooxygenases has been extensively used as a monitoring tool to detect contamination of water bodies by cytochrome P450-inducing agents. In this study we evaluated the activities of ethoxy- (EROD), methoxy- (MROD) and pentoxy- (PROD) resorufin-O-dealkylases in the liver of Nile tilapias (Oreochromis niloticus) collected at the Guandu river, at a reference clean site (Lake 1) and at two other sampling sites (Lakes 2 and 3) in Rio de Janeiro state, Brazil. Alkoxyresorufin-O-dealkylases were measured fluorimetrically in the hepatic S9 fraction. EROD (17.7-fold), MROD (14.2-fold) as well as PROD activities were considerably higher in tilapias from Guandu river. A moderate increase of EROD (5.0-fold) and MROD (5.4-fold) was also found in tilapias from Lake 3. These findings suggest that Guandu river watershed, the main source of urban drinking water supply in Rio de Janeiro, is polluted with CYP1A-inducing xenobiotics. Furthermore, we also found a good linear relationship between EROD and MROD, a finding that agrees with the hypothesis that the two reactions are catalysed by the same CYP1A isoform in O. niloticus.     

Kinetics of photodegradation and ozonation of pentachlorophenol

The oxidation of 2,3,4,5,6-pentachlorophenol (PCP) has been carried out by a photodecomposition process using a polychromatic UV irradiation, and by an ozonation process. In the photodegradation process, the pH accelerated the decomposition rate and the approximate first-order rate constants were evaluated, with values between 0.16+/-0.005 min(-1) at pH=3 and 0.26+/-0.007 min(-1) at pH=9. A more rigorous kinetic study led to the determination of the quantum yields of the reaction, with values of 200+/-7x10(-3) mol/Eins for pH=3 and 22+/-1.1x10(-3) mol/Eins for pH=9. In the ozonation process, the rate constants for the reaction between ozone and PCP were determined by means of a competition kinetics, with values in the range from 0.67x10(5) to 314x10(5) l/mols. The specific rate constants for the un-dissociated and dissociated forms of PCP were also calculated. Finally, in both processes, the intermediate reaction products were identified, the most important being tetrachlorocatechol, tetrachlorohydroquinone and tetra-p-chlorobenzoquinone. Free chloride ion released, which was favored at high pHs, was also followed in both processes.     

Spectrophotometric determination of the fungicide captan

A spectrophotometric method for the determination of the fungicide captan has been developed based on its reaction with thiosemicarbazide. The absorbance was measured at 315 nm. The effects of the proportion of water, thiosemicarbazide concentration, pH and temperature on this reaction was studied to select the best chemical conditions. The calibration graph was obtained between 1.2 and 30 ppm and the detection limit is 0.5 ppm. The RSD (n = 10) was 1.34%. Possible interference of various pesticides was examined. The method was applied to the determination of captan in agrochemical formulations. Results agree well with the labelled values and also with results that were obtained by a polarographic method.     

Comparative study on the susceptibility of freshwater species to copper-based pesticides

Copper compounds have been intentionally introduced into water bodies as aquatic plant herbicides, algicides and molluscicides. Copper-based fertilizers and fungicides have been widely used in agriculture as well. Despite the fact that copper is an essential element for all biota, elevated concentrations of this metal have been shown to affect a variety of aquatic organisms. Nonetheless, comparative studies on the susceptibility of different freshwater species to copper compounds have seldom been performed. This study was conducted to compare toxicity of copper-based pesticides (copper oxychloride, cuprous oxide and copper sulfate) to different freshwater target (Raphidocelis subcapitata, a planktonic alga and Biomphalaria glabrata, a snail) and non-target (Daphnia similis, a planktonic crustacean and Danio rerio, a fish) organisms. Test water parameters were as follows: pH = 7.4 +/- 0.1; hardness 44 +/- 1 mg/l as CaCO3; DO 8-9 mg/l at the beginning and > 4 mg/l at the end; temperature, fish and snails 25 +/- 1 degrees C, Daphnia 20 +/- 2 degrees C, algae 24 +/- 1 degrees C. D. similis (immobilization), 48-h EC50s (95% CLs) ranging from 0.013 (0.011-0.016) to 0.043 (0.033-0.057) mg Cu/l, and R. subcapitata (growth inhibition), 96-h IC50s from 0.071 (0.045-0.099) to 0.137 (0.090-0.174) mg Cu/l, were the most susceptible species. B. glabrata (lethality), 48-h LC50s from 0.179 (0.102-0.270) to 0.854 (0.553-1.457) mg Cu/l, and D. rerio (lethality), 48-h LC50s 0.063 (0.045-0.089), 0.192 (0.133-0.272) and 0.714 (0.494-1.016) mg Cu/l, were less susceptible than Daphnia to copper-based pesticides. Findings from the present study therefore suggest that increased levels of copper in water bodies is likely to adversely affect a variety of aquatic species.     

The role of environmental and fisheries multi-controls in white seabream (Diplodus sargus) artisanal fisheries in Portuguese coast

Evaluating the effects of fishing and environmental factors on fish populations are fundamental tenets of fisheries science. In this study, we assess associations between environmental variables (sea surface temperature; North Atlantic Oscillation index; upwelling; wind magnitude; westerly winds; northerly winds; river discharge) and fishing variables (fishing effort) in Diplodus sagus catch rates accounting for regional analyses (northwest coast; southwest coast and Algarve—Algarve south coast). Different time series models for data fitting (multi-model approach) were used. The models were lagged, according to species fishing recruitment age based on the hypothesis that fisheries catches depend on larvae recruitment and survivorship. D. sargus catch rates across areas were unrelated to fishing effort but correlated to environmental variables, with seasonal events explaining much of the variability in trends. On the northwestern coast, the catch rates were mainly set by sea surface temperature (SST) and wind magnitude; however, southwestern coast catch rates were set by NAO winter. On the south coast, only one statistical model (SST, upwelling and westerly winds) associated spring conditions with D. sargus catch rates. The multi-model approach revealed autumn, winter and spring seasonal effects to be related with northwest, southwest and Algarve coastal catch rates, respectively, indicating a possible coastal longitudinal gradient related with given periods of spawning and larval availability. The metadata analysis yielded different results from the regional analyses. In summary, marine resource management should take regional environment characteristics and variability into account when determining sustainable catch rates in given areas for species with high habitat site fidelity.     

Environmental influence on commercial fishery landings of small pelagic fish in Portugal

Small pelagic fishes are particularly abundant in areas with high environmental variability (zones of coastal upwelling and areas of tidal mixing and river discharge), and because of this, their abundance suffers large inter-annual and inter-decadal fluctuations. In Portugal, the most important species in terms of landings are European sardine, Atlantic horse mackerel and Atlantic chub mackerel. Small pelagic fish landings account for 62.8 % of the total fish biomass and represent 32.7 % of the economical value of all catches. We have investigated trends in landings of these small pelagic fishes and detected the effects of environmental factors in this fishery. In order to explain the variability of landings of small pelagic fishes, we have used official landings (1965–2012) for trawling and purse seine fisheries and applied generalized linear models, using the North Atlantic Oscillation index (NAO) (annual and winter NAO index), sea surface temperature (SST), wind data (strength and North–South and East–West wind components) and rainfall, as explanatory variables. Regression analysis was used to describe the relationship between landings and SST. The models explained between 50.16 and 51.07 % of the variability of the LPUE, with the most important factors being winter NAO index, SST and wind strength. The LPUE of European sardine and Atlantic horse mackerel was negatively correlated with SST, and LPUE of Atlantic chub mackerel was positively correlated with SST. The use of landings of three important species of small pelagic fishes allowed the detection of variations in landings associated with changes in sea water temperature and NAO index.     

Monitoring of polycyclic aromatic hydrocarbons in a produced water disposal area in the Potiguar Basin,Brazilian equatorial margin

Environmental Science and Pollution Research - The Potiguar Basin has oil and gas production fields offshore and onshore. All treated produced water (PW) from these fields is discharged through...     

The role of urban green infrastructure in mitigating land surface temperature in Bobo-Dioulasso,Burkina Faso

Green infrastructure in developed countries has been used as a climate change adaptation strategy to lower increased temperatures in cities. But, the use of green infrastructure to provide ecosystem services and increase resilience is largely overlooked in climate change and urban policies in the developing world. This study analyzed the role of urbanization and green infrastructure on urban surface temperatures in Bobo-Dioulasso, Burkina Faso, in sub-Saharan Africa. We use available geospatial data and techniques to spatially and temporally explore urbanization and land surface temperatures (LSTs) over 20 years. The effect of specific green infrastructure areas in the city on LSTs was also analyzed. Results show increased urbanization rates and increased temperature trends across time and space. But, LST in green infrastructure areas was indeed lower than adjacent impervious, urbanized areas. Seasonal phenological differences due to rainfall patterns, available planting space, and site limitations should be accounted for to maximize temperature reduction benefits. We discuss an approach on how study findings and urban and peri-urban agriculture and forestry are being used for policy uptake and formulation in the field of climate change, food security, and urbanization by the municipal government in this city in Burkina Faso.     

能源在可持续发展中的作用:拉丁美洲能源政策分析的要素

与能源政策和可持续发展之间的关系有关的决策的制定应该不仅包括对当前问题的鉴定和对未来影响的评估,而且为了增加这些政策成功的可能性还包括有关各方面的积极参与.因为一切环境政策都有着非常复杂的环境内涵,仅仅采用有限的技术手段或系统的运作可能很难找到合适的解决方案.     

The influence of axle position and the use of accessories on the activity of upper limb muscles during manual wheelchair propulsion

Introduction. Wheelchair configuration is an important factor influencing the ergonomics of the user–device interface and, from a biomechanical point of view, small changes in chair setup may have a positive influence on the demand on the upper limbs during manual propulsion. This study aimed to investigate the influence of the position of the rear wheels’ axle and the use of accessories on the activity of upper limb muscles during manual wheelchair propulsion. Methods. Electromyography signals of the biceps, triceps, anterior deltoids and pectoralis major were collected for 11 able-bodied subjects in a wheelchair propulsion protocol with four different wheelchair configurations (differing in axle position and the use of accessories) on a straightforward sprint and a slalom course. Results. With accessories, moving the axle forward led to a decrease in the activity of all muscles in both the straightforward sprint (significant differences in triceps, anterior deltoids and biceps) and the slalom course (significant difference in anterior deltoids and biceps). However, when propelling the chair without accessories, no difference was found related to axle position. Conclusion. Changes in wheelchair configuration can influence the ergonomics of manual wheelchair propulsion. Reducing the biomechanical loads may benefit users’ mobility, independence and social participation.