Dehalogenation of polychlorinated biphenyls and polybrominated diphenyl ethers using a hybrid bioinorganic catalyst

The environmentally prevalent polybrominated diphenyl ether (PBDE) #47 and polychlorinated biphenyls (PCBs) #28 and #118 were challenged for 24 hours with a novel biomass-supported Pd catalyst (Bio-Pd(0)). Analysis of the products via GC-MS revealed the Bio-Pd(0) to cause the challenged compounds to undergo stepwise dehalogenation with preferential loss of the least sterically hindered halogen atom. A mass balance for PCB #28 showed that it is degraded to three dichlorobiphenyls (33.9%), two monochlorobiphenyls (12%), and biphenyl (30.7%). The remaining mass was starting material. In contrast, while PCB #118 underwent degradation to yield five tetra- and five trichlorinated biphenyls, no less chlorinated products or biphenyl were detected, and the total mass of degraded products was 0.3%. Although the Bio-Pd(0) material was developed for treatment of PCBs, a mass balance for PBDE #47 showed that the biocatalyst could prove a potentially useful method for treatment of PBDEs. Specifically, 10% of PBDE #47 was converted to identifiable lower brominated congeners, predominantly the tribrominated PBDE #17 and the dibrominated PBDE #4, 75% remained intact, while 15% of the starting mass was unaccounted for.     

Sensitivity analysis of a parameterization of the stomatal component of the DO3SE model for Quercus ilex to estimate ozone fluxes

A sensitivity analysis of a proposed parameterization of the stomatal conductance (g(s)) module of the European ozone deposition model (DO(3)SE) for Quercus ilex was performed. The performance of the model was tested against measured g(s) in the field at three sites in Spain. The best fit of the model was found for those sites, or during those periods, facing no or mild stress conditions, but a worse performance was found under severe drought or temperature stress, mostly occurring at continental sites. The best performance was obtained when both f(phen) and f(SWP) were included. A local parameterization accounting for the lower temperatures recorded in winter and the higher water shortage at the continental sites resulted in a better performance of the model. The overall results indicate that two different parameterizations of the model are needed, one for marine-influenced sites and another one for continental sites.     

Carbon footprint in corporate logistics operations in the food sector

Global warming is negatively affecting the environment of the planet. This situation has led to the development of international standards, such as the International Organisation for Standardization's DIS 14064‐1 and the Greenhouse Gas Protocol Corporate Standard, both of which measure corporate carbon footprints. These standards provide guidelines that can be applied to different organizational sectors. However, these are not sufficient for controlling the reduction of carbon emissions, because although they propose the use of indicators, they do not explicitly define them. In addition, in the case of emissions from wastewater treatment, they only suggest that the emissions associated with this process be considered. In the present study, an eight‐step, unified methodology based on these two international standards is proposed, focusing on direct emissions. Moreover, the step‐by‐step to data collection, calculations, and the required indicators to control the emissions are defined. The first scope considers direct emissions from sources that are owned or controlled by the company. Methane generation measurement from wastewater treatment has been included in the methodology within Scope 1, as it is the second most polluting gas after carbon dioxide, both of which give rise to global warming. The proposed methodology was tested as a case study in one of the most important companies in the food sector in Colombia.     

A case study of social behaviour in a natural disaster: the olivares landslide (Spain)

The modern sociological literature on disasters highlights the fact that many of the ideas about human behaviour in disasters which were long considered as valid, are wrong. The main discovery is based on the fact that situations of crisis increase people's moral principles and capability of response. This paper illustrates some of these ideas, in a case study of a village which was struck by a natural disaster in the north of Granada (Spain) in 1986. The population's attitude revealed a huge potential of resources that were underestimated by professionals of disaster management. The analysis shows that it is necessary to bring civil protection systems and the population's capability of response into close harmony.     

Genetic variability and level of differentiation in North Sea and Baltic Sea populations of the green alga<Emphasis Type="Italic"> Cladophora rupestris</Emphasis>

Cladophora rupestris is a perennial filamentous macroalga belonging to the Chlorophyta. It is widely distributed on both sides of the northern Atlantic Ocean and penetrates into the brackish Baltic Sea down to ca. 4 psu salinity. In this paper we present evidence for genetic differentiation of a Baltic form of this marine alga. We assessed genetic structure within and among 11 populations ranging along a salinity gradient from the Norwegian coast to the northern Baltic Sea proper. Samples of 328 individuals were studied using starch-gel protein electrophoresis to evaluate genetic variability and interpopulation differentiation based on allozymes. Of 11 loci examined, only one was polymorphic. For this locus, encoding superoxide dismutase (SOD-3), a total of seven alleles were distinguished. We found two genetically differentiated groups of populations of C. rupestris, one Baltic Sea group and one North Sea group, with a distinct border in the southern Kattegat near the entrance to the Baltic Sea. The genetic differentiation for SOD-3, expressed as pairwise F_ST values between the populations, was generally higher within the Baltic Sea group (0.10-0.43) than within the North Sea group (0.05-0.10); in the latter group also fewer pairs of populations differed significantly. Pairs of populations from different groups had the highest F_ST values (0.20-0.60). Hierarchical analysis of variance showed that 29.6% of the total variation in the SOD-3 locus was explained by variation between the two groups, while only 4.2% was explained by variation among the populations within the groups. The remaining variation (66.2%) was found within the populations.     

Dufour's gland secretion of the queen honeybee (Apis mellifera): an egg discriminator pheromone or a queen signal?

The role of Dufour's gland secretion as an egg discriminator pheromone was reevaluated by simultaneously exposing workers to two combs, one containing queen- or worker-laid eggs and the second containing treated or untreated worker-laid eggs. Treatments included extracts of Dufour's gland secretion as well as the synthetic esters that were identified in the secretion. Policing was clearly detected both in queenright and queenless colonies by the swift removal of worker, but not of queen eggs. However, neither the glandular secretion nor its synthetic ester constituents were able to protect worker-born eggs from policing. Treated worker eggs were removed significantly faster than queen eggs, and at the same rate as non-treated worker eggs. These results are not consistent with the hypothesis that the secretion serves as an egg-marking pheromone. Chemical analyses of the queen abdominal tips revealed the presence of Dufour's esters, indicating that the glandular secretion oozes out and spreads over the cuticle around the genital chamber. However, contamination while ovipositing may also explain the minute amounts of these esters that were detected on the egg surface. Dufour's gland caste-specific composition suggests that in queens it may constitute a signal that plays a role in queen-worker interactions. Attraction bioassays revealed that the queen secretion, but not that of workers, is very attractive to workers. When applied either on a glass slide or on another worker, a retinue formed around the "surrogate queen". We conclude that Dufour's gland secretion constitutes part of a complex queen signal that is the basis for the social integrity of the honeybee colony.     

Seasonal and depth related variation in the photosynthesis–irradiance response of<Emphasis Type="Italic"> Ecklonia radiata</Emphasis> (Phaeophyta,Laminariales) at West Island,South Australia

The photosynthesis–irradiance response of Ecklonia radiata (C. Agardh) J. Agardh, a common kelp in the temperate southern hemisphere, was investigated in situ throughout the year and across a depth profile at West Island, South Australia. Temperature and irradiance environment altered throughout the year, varying at 3 m between 14–20°C and 279–705 mol photons m^–2 s^–1. Photosynthetic capacity (P_m) varied throughout the year between 177–278 mol O₂ g^–1 dry wt h^–1 at 3 m and 133–348 mol O₂ g^–1 dry wt h^–1 at 10 m. The irradiance required for sub-saturation of photosynthesis (E_k) varied between 97–152 and 81–142 mol photons m^–2 s^–1 for 3 m and 10 m respectively, and the respiration rate varied between 15–36 and 13–20 mol O₂ g^–1 dry wt h^–1 for 3 m and 10 m. A clear seasonal change in photokinetic parameters was detected and provided strong evidence for a seasonal acclimation response. During winter an increase in the efficiency of light utilisation at low irradiance () was accompanied by a decrease in both E_k and that required for photosynthetic compensation. P_m also increased during the winter and autumn months and respiratory requirements decreased. These changes enable E. radiata to display an optimal photosynthetic performance throughout the year despite significant changes in the surrounding environment.Communicated by P.W. Sammarco, Chauvin     

Trends in atmospheric ammonium concentrations in relation to atmospheric sulfate and local agriculture

Ammonium (NH(4)(+)) concentrations in air and precipitation at the Institute of Ecosystem Studies (IES) in southeastern New York, USA declined over an 11-year period from 1988 to 1999, but increased from 1999 to 2001. These trends in particulate NH(4)(+) correlated well with trends in particulate SO(4)(2-) over the 1988-2001 period. The NH(4)(+) trends were not as well correlated with local cattle and milk production, which declined continuously throughout the period. This suggests that regional transport of SO(4)(2-) may have a greater impact on concentrations of NH(4)(+) and subsequent deposition than local agricultural emissions of NH(3). Ammonium concentrations in precipitation correlated significantly with precipitation SO(4)(2-) concentrations for the 1984-2001 period although NH(4)(+) in precipitation increased after 1999 and SO(4)(2-) in precipitation continued to decline after 1999. The correlation between NH(4)(+) and SO(4)(2-) was stronger for particulates than for precipitation. Particulate NH(4)(+) concentrations were also correlated with particulate SO(4)(2-) concentrations at 31 of 35 eastern U.S. CASTNet sites that had at least 10 years of data. Air concentrations of NH(4)(+) and SO(4)(2-) were more strongly correlated at the sites that were located within an agricultural landscape than in forested sites. At most of the sites there was either no trend or a decrease in NH(4)(+) dry deposition during the 1988-2001 period. The sites that showed an increasing trend in NH(4)(+) dry deposition were generally located in the southeastern U.S. The results of this study suggest that, in the northeastern U.S., air concentrations of NH(4)(+) and subsequent deposition may be more closely linked to SO(4)(2-) and thus SO(2) emissions than with NH(3) emissions. These results also suggest that reductions in S emissions have reduced NH(4)(+) transport to and NH(4)(+)-N deposition in the Northeast.     

Cover crops and natural vegetation mulch effect achieved by mechanical management with lateral rotary mower in weed population dynamics in citrus

The aim of this study was to obtain information on practical weed management in order to reduce the use of herbicides thereby contributing to the sustainable development of citrus crop. The experiment was carried out under field conditions at the experimental area of the Department of Vegetal Production at the College of Agriculture "Luiz de Queiroz," Piracicaba, SP, Brazil, during the season 2002-2003. Influence of mulches produced by four types of vegetations on the dynamic population of weeds in the line of citrus crop (Citrus sinensis (L.) Osbeck) was evaluated. The experimental design was of factorial randomized blocks (4 x 2), where the treatments were: (i) four types of vegetation: Dolichos lablab L., Cajanus cajan (L.) Millsp, Penisetum glaucum (L.) Leeke, and the natural infestation composed basically by Panicum maximum Jacq.; and (ii) two types of fertilization: directed under canopy and broadcast. Mechanical management of the different vegetations was accomplished using a lateral rotary mower, KAMAQ, I model NINJA MAC 260, projected to release the green cut material under crop canopy, forming a mulch layer. The studied parameters were: (i) counting of weeds per m2 in the crop line after 30, 60, 90, 180, and 210 days following the cutting of existing vegetation; (ii) percentage of covered area by weeds; and (iii) some chemical properties of the soil. It was observed that the natural infestation showed a better weed control when compared with the other treatments, and that the broadcast fertilization, regardless of coverage used, presented a lower number of weeds.     

Impact of wildfires on the air quality of Mexico City, 1992-1999

Wildfires in Mexico increased in 1998, compared to information for the last 6 years. The average number of wildfires in the Mexico City Metropolitan Area (MCMA) for this year (1998) were 58% (1916 events) more events than the 1992-1997 (average cases 1217 events). Mexico City affected area corresponds to 1.3% of the national affected area. The purpose of this paper is to evaluate the impact on the particles air quality due to the wildfire emissions at the MCMA and surrounding areas. Using the corresponding US EPA emission factors for wildfires, the tons of particulate matter, nitrogen oxides, carbon monoxide, and total hydrocarbons emitted by this source for the MCMA case were obtained. The calculated emissions during wildfires were correlated with the levels of particles present in the atmosphere. A comparison of the concentration levels of particles, both as PM10 as well as TSP, were made for the years 1992-1998, during wet and dry season, being March, April, and May the critical months due to the presence of wildfires. A good correlation is observed between particulate wildfire emissions and particulate air quality, being stronger for TSP. A clear impact on the particles air quality due to the increase of wildfires in 1998, is observed when this year is compared with 1997, presenting an increment of 200-300% for some monitoring stations.