High surface area materials prepared from sewage sludge-based precursors

This paper focuses on physical activation (CO2) and chemical activation (H3PO4, NaOH and KOH) of sewage sludge-based precursors. Our results show that (i) a simple acid washing treatment leads to a significant increase in the adsorption capacity of some precursors; (ii) under the experimental conditions tested, CO2 physical activation and chemical activation with H3PO4 were ineffective for an efficient porosity development and (iii) choosing an appropriate protocol, it is possible to obtain highly porous materials (700-1700 m2 g(-1)) by chemical activation of sludge-based precursors with alkaline hydroxides. The efficiency of the chemical activation with NaOH or KOH is very much influenced by the method used for mixing the activating agent and the precursor. The BET values of the materials obtained when physically mixing ground hydroxides with the precursor almost doubled the values obtained if other mixing methods are employed. Increasing the hydroxide:precursor ratio leads to an enhancement of the adsorption capacity of the adsorbents, with BET values ranging from 689 to 1224 m2 g(-1) for NaOH activation and from 853 to 1686 m2 g(-1) for KOH activation.     

Surveillance programme on dioxin levels in soils in the Campo de Gibraltar (southwest Spain)

The results of an epidemiologic study undertaken by the Spanish Council for Scientific Research (CSIC) after commission by the Spanish Parliament indicated that Huelva and Cádiz were the zones in Andalusia with elevated risk of cancer. A 6% (women) and 10% (men) cancer mortality excess was observed with respect to the other six Andalusian provinces. Huelva and Cádiz are located in the south-western region of Spain, and are characterized by a strong industrial activity concentrated in several industrial sites. This situation led to two environmental surveys in these areas, in which the presence of dioxins was studied among other parameters. A PCDD/F assessment in soils of the Campo de Gibraltar (Cádiz) was carried out from June 2003 to June 2004. A total of 20 samples were collected in this study divided in two sampling campaigns. The first 10 samples were taken in locations affected by high industrial activity zones as well as in landfills (hotspots). The rest of the samples were collected in areas that were not expected to be contaminated, such as agricultural zones and forests. I-TEQ values of the samples ranged from 0.26 to 15.08 ng/kg dm. In all, 85% of the samples were below the limit of 5 ng I-TEQ/kg I-TEQ concentrations of three samples only surpassed this limit. These zones corresponded to a landfill, a quarry used for dumping chemical product containers and a sample from the sewage system of the industrial site. These sites were used neither for agricultural nor for public purposes.     

Multi-technique characterization of a nuclear bomb particle from the Palomares accident

A January 1966 accident dispersed Pu and other nuclear bomb materials in the vicinity of Palomares, a village in southeastern Spain. Radioactive particles were identified in a soil sample collected in 1998 and analytical results obtained from one of the isolated particles are presented here. Isolation of the particle was performed using gamma-ray spectrometry and imaging plates. Scanning electron microscopy with X-ray microanalysis revealed the presence of U and Pu as well as Pb and Fe in the particle of approximately 10microm diameter. Radioisotopes of U, Pu, and Am were quantified using radiometric methods, inductively coupled plasma mass spectrometry and secondary ion mass spectrometry. The elevated (235)U/(238)U atom ratio indicates enriched U, and the Pu atom ratios are consistent with weapons-grade material. This work demonstrates that the analysis of individual particles provides information not available through bulk sample analysis.     

Optimal Environmental Policy for a Polluting Monopoly with Abatement Costs: Taxes Versus Standards

In this paper, we characterize the optimal environmental policy for a polluting monopoly that devotes resources to abatement activities when damages are caused by a stock pollutant. With this aim, we calculate the stagewise feedback Stackelberg equilibrium of a (differential) policy game where the regulator is the leader and the monopolist is the follower. Our analysis shows that the first-best policy consists of applying a Pigouvian tax and a subsidy on production equal to the difference between the price and the marginal revenue. However, for a stock pollutant, the Pigouvian tax is not equal to the marginal damages but is given by the difference between the social and private valuation of the pollution stock. On the other hand, if a second-best emission tax is used, the tax is lower than the Pigouvian tax and the difference decreases with the price elasticity of the demand. Finally, we find that taxes and standards are equivalent in a second-best setting. In the second part of the paper, we solve a linear-quadratic differential game and we obtain that the first-best tax increases with the pollution stock whereas the subsidy decreases. Moreover, the tax is negative for low values of the pollution stock, i.e., for low values of the pollution stock, we obtain that the social valuation of the stock is lower than the private valuation. Furthermore, when a second-best policy is applied, the steady-state pollution stock is lower than the steady-state pollution stock associated with the efficient outcome.     

Ecological distribution conflicts as forces for sustainability: an overview and conceptual framework

Can ecological distribution conflicts turn into forces for sustainability? This overview paper addresses in a systematic conceptual manner the question of why, through whom, how, and when conflicts over the use of the environment may take an active role in shaping transitions toward sustainability. It presents a conceptual framework that schematically maps out the linkages between (a) patterns of (unsustainable) social metabolism, (b) the emergence of ecological distribution conflicts, (c) the rise of environmental justice movements, and (d) their potential contributions for sustainability transitions. The ways how these four processes can influence each other are multi-faceted and often not a foretold story. Yet, ecological distribution conflicts can have an important role for sustainability, because they relentlessly bring to light conflicting values over the environment as well as unsustainable resource uses affecting people and the planet. Environmental justice movements, born out of such conflicts, become key actors in politicizing such unsustainable resource uses, but moreover, they take sometimes also radical actions to stop them. By drawing on creative forms of mobilizations and diverse repertoires of action to effectively reduce unsustainabilities, they can turn from ‘victims’ of environmental injustices into ‘warriors’ for sustainability. But when will improvements in sustainability be lasting? By looking at the overall dynamics between the four processes, we aim to foster a more systematic understanding of the dynamics and roles of ecological distribution conflicts within sustainability processes.     

Physical Characterization of Biodegradable Films Based on Chitosan,Polyvinyl Alcohol and <Emphasis Type="Italic">Opuntia</Emphasis> Mucilage

This study aimed to develop and characterize biodegradable films containing mucilage, chitosan and polyvinyl alcohol (PVA) in different concentrations. The films were prepared by casting on glass plates using glycerol as plasticizer. Mechanical properties, water vapor and oxygen barrier, as well as the interaction with water, were measured. The compatibility of the film-forming components and the uniformity of the films were determined by zeta potential and SEM, respectively. The glycerol and mucilage allowed obtaining more hydrophilic films. The barrier properties of the films made from 100 % chitosan were similar to composed films containing PVA up to 40 %. The results of this study suggest that the interaction between chitosan and mucilage could increase water vapor permeability. The films prepared from either 100 % chitosan or PVA showed a more hydrophobic behavior as compared to the composed films. The films were homogenous since no boundary or separation of components was observed, indicating a good compatibility of the components in the films.     

Wind energy in the Isthmus of Tehuantepec: conflicts and social implications

Social acceptance is fundamental, and directly affects the installation of wind farms. In this paper, the factors that have had the greatest influence on the development of wind energy in the Itsmo region of Tehuantepec, Mexico are identified. The data were collected face to face through a semi-structured questionnaire of 31 people: owners, municipal authorities, opposition groups, and academic members. The results of the interview highlight the social impact, the lack of application, and concerning ILO Convention 169, the abuse of community rights. As a result, people interviewed perceive that the environmental impact of the installation, and operation of wind farms has been ambivalent: positive due to the intrinsic benefits that wind energy generates compared to other energy sources, and negative in terms of affectation by the noise, and the landscape. However, the income received by the owners of land in which wind facilities are located is lower compared to other parts of the world. In general, the facts show a disintegration between the authorities (federal, state, and municipal), universities are isolated from wind projects, communities are not consulted in projects, and large companies are the main beneficiaries.

     

Nitrate and phosphate leaching in a Phaeozem soil treated with biosolids,composted biosolids and inorganic fertilizers

The use of organic wastes in agriculture may increase the production of crops by incorporating organic matter and nutrients into the soil, and by improving its physical characteristics; however, this use may cause environmental problems such as the leaching of certain ions. The objective of this study was to establish possible nitrogen and phosphorus leaching under real field conditions in Phaeozem soils. The experimental work was performed in a corn (Zea mays L.) field where three plots were conditioned with inorganic fertilizer, three plots with 4.5 Mg ha^?1 of biosolids on dry basis, and three plots with the same amount of composted biosolids. The quality of biosolids and composted biosolids complied with the Mexican Official Standards. Soil water samples were collected with suction cups during two agricultural cycles and were analysed. Soil samples were also taken and analysed.The N–NO₃ concentrations in soil water fluctuated between 0.9 and 98 mg L^?1 in the composted biosolid treatment, between 0.7 and 64 mg L^?1 in the biosolid treatment, and between 1 and 61 mg L^?1 in the inorganic fertilizer treatment. The maximum concentration of N–NO₂ and N–NH₃ in soil water was 1.02 and 2.65 mg L^?1, respectively. The greatest percentage of nitrogen leached is produced when inorganic fertilizer is used (37.4% and 24.0% N leached in the first and second years, respectively), followed by composted biosolids (17.1% and 13.5% N leached in the first and second years, respectively) and last by biosolids (11% for both years). This difference could be related to the form in which nitrogen is present in the fertilizers, while commercial fertilizer is as inorganic nitrogen, organic wastes are basically presented as organic nitrogen. The maximum ${\text{PO}}_4^{3-}$ concentration in soil water was 1.9 mg L^?1 in the composted biosolid treatment, 1.7 mg L^?1 in the biosolid treatment and 0.9 mg L^?1 in the inorganic fertilizer treatment. The estimated percentage of leached phosphorus was less than 1% for all treatments. The minimum leaching that occurred seemed to be due to a sorption–precipitation process.     

Pilot study on the influence of stress caused by the need to combine work and family on occupational accidents in working women

The influx of a large number of women into the workforce involves the need for these women to combine family and work responsibilities. Multiple roles lead to work–family conflict. This study analyzes the influence of work–family conflict on the causes of minor occupational accidents suffered by working women. A survey was done on working women in the Madrid region, who had suffered a minor occupational accident in 2004. The main finding was that nearly half of the women with children considered that the stress and fatigue caused by trying to combine work and family played a part in the accident; 21% of the respondents whose accidents took place while traveling to or from work and 11% the respondents who suffered the accident in the workplace said that family reasons played a part. Additionally, 50% of the women suffered after-effects as a result of the accident; children had to change their routine in almost 1 in 4 cases; nearly a quarter of the respondents said their work situation had been temporarily modified. This point to a need for polices that encourage men and employers to contribute more to solve work–family conflicts.