Chemical and biological characterization of slaughterhouse wastes compost

The chemical and biological properties of compost made from yard trimmings (YT) composted alone or mixed with slaughterhouse wastes (SHW) were evaluated in seven phases. Mixtures were weighed in a 2:1 proportion (YT:SHW) and placed in composting bins (0.91 m2). Temperature was recorded to determine the time (d) needed to reach the first (1HC) and second heat cycles (2HC). Composting characteristics were measured at 0 d, at the peak of the 1HC and 2HC, and at maturation (0, 20, 50 and 70 d). During 1HC, bacterial isolates were cultivated in both treatments and identified using the Biolog System. Chemical composition was statistically analyzed using a 2 (layers of SHW)x7 (composting phases) factorial arrangement of treatments with the ANOVA procedure of SAS. The pH was neutral for YT and ranged from 7.41 to 6.82 for SHW throughout the process. There was a decrease in organic matter (OM) and carbon (C), and a relative increase in nitrogen (N) in both treatments. At 70 d of maturation, C:N values were similar between treatments, but lower (P>0.05) than the initial values. Final N concentration was higher (P>0.05) for the treatment with SHW. Only the SHW treatment exhibited thermophilic temperatures. At the 1HC in both treatments, different populations of bacteria responsible for the breakdown of OM were identified showing an active heterogeneous population. The presence of pathogenic microorganisms was not detected in treatments containing SHW.     

Sub-soil contamination due to oil spills in zones surrounding oil pipeline-pump stations and oil pipeline right-of-ways in Southwest-Mexico

Oil spills due to oil pipelines is a very frequent problem in Mexico. Petroleos Mexicanos (PEMEX), very concerned with the environmental agenda, has been developing inspection and correction plans for zones around oil pipelines pumping stations and pipeline right-of-way. These stations are located at regular intervals of kilometres along the pipelines. In this study, two sections of an oil pipeline and two pipeline pumping stations zones are characterized in terms of the presence of Total Petroleum Hydrocarbons (TPHs) and Polycyclic Aromatic Hydrocarbons (PAHs). The study comprehends sampling of the areas, delimitation of contamination in the vertical and horizontal extension, analysis of the sampled soils regarding TPHs content and, in some cases, the 16 PAHs considered as priority by USEPA, calculation of areas and volumes contaminated (according to Mexican legislation, specifically NOM-EM-138-ECOL-2002) and, finally, a proposal for the best remediation techniques suitable for the contamination levels and the localization of contaminants.     

Diel cycles of arsenic speciation due to photooxidation in acid mine drainage from the Iberian Pyrite Belt (Sw Spain)

Twenty four hours diel cycles of arsenic speciation in Acid Mine Drainage (AMD) due to photooxidation have been reported for the first time. AMD samples were taken during 48 h (31st March and 1st April, 2005) at 6 h intervals from the effluent of a massive abandoned polymetallic sulphide mine of the Iberian Pyrite Belt (Sw Spain). Samples were preserved in situ using cationic exchange prior to analysis by coupled high performance liquid chromatography, hydride generation and atomic fluorescence spectrometry (HPLC-HG-AFS) for arsenic speciation. The results indicated the presence of inorganic arsenic species with daily means of 262mugl(-1) for As(V) and 107 microg l(-1) for As(III). No marked diel trend was observed for As(V). However, a marked diel trend was observed for As(III) in the two studied days, with maximum concentrations during nighttime (141-143 microg l(-1)) and minimum concentrations at daytime (72-77 microg l(-1)). This difference in concentration during daytime and nighttime is ca. 100%. A similar diel cycle was observed for iron. An explanation for the arsenic diel cycles observed is the light induced photooxidation of As(III) and the elimination of As(V) due to its adsorption onto Fe precipitates during the daytime. Furthermore, the diel changes in arsenic speciation emphasize the importance of designing suitable sampling strategies in AMD systems.     

Utilizing international networks for accelerating research and learning in transformational sustainability science

A promising approach for addressing sustainability problems is to recognize the unique conditions of a particular place, such as problem features and solution capabilities, and adopt and adapt solutions developed at other places around the world. Therefore, research and teaching in international networks becomes critical, as it allows for accelerating learning by sharing problem understandings, successful solutions, and important contextual considerations. This article identifies eight distinct types of research and teaching collaborations in international networks that can support such accelerated learning. The four research types are, with increasing intensity of collaboration: (1) solution adoption; (2) solution consultation; (3) joint research on different problems; and (4) joint research on similar problems. The four teaching types are, with increasing intensity of collaboration: (1) adopted course; (2) course with visiting faculty; (3) joint course with traveling faculty; and (4) joint course with traveling students. The typology is illustrated by extending existing research and teaching projects on urban sustainability in the International Network of Programs in Sustainability, with partner universities from Europe, North America, Asia, and Africa. The article concludes with challenges and strategies for extending individual projects into collaborations in international networks.     

Assessment of Aquifer Vulnerability in an Agricultural Area in Spain Using the DRASTIC Model

The assessment of aquifer vulnerability is a very important task, especially in agricultural areas because the quality and availability of groundwater affects both the sustainability of agriculture and the quality of life. In this study, an integrated approach is considered, with the use of the generic and agricultural DRASTIC models as well as a geographic information system (GIS), to assess groundwater vulnerability in the agricultural area of Barrax, in the province of Albacete, in Spain. Seven parameters—depth to water, net recharge, aquifer media, soil media, topography, impact of vadose zone media, and hydraulic conductivity of the aquifer (DRASTIC)—have been considered as weighted layers to enable an accurate groundwater risk mapping. The results of the generic DRASTIC model indicated very low vulnerability to contamination for Barrax groundwater due to limited urban and industrial development in the wider area. However, agricultural activities impose pressure to groundwater resources and the results of the agricultural DRASTIC model show that 6.86% of the study area is characterized by very high, 2.29% by high, 47.28% by medium, 38.28% by low, and the remaining 5.29% by no vulnerability to groundwater contamination. The distribution of nitrate concentration in groundwater in the area under study is quite well correlated with the agricultural DRASTIC vulnerability index. Sensitivity analysis was also performed to acknowledge statistical uncertainty in the estimation of each parameter used, to assess its impact, and thus to identify the most critical parameters that require further investigation. Depth to water and impact of vadose zone are the parameters that had the most noticeable impact on the generic DRASTIC vulnerability index followed by the soil media and topography. In contrast, the agricultural DRASTIC method is more sensitive to the removal of the depth to water parameter followed by the topography and the soil media parameters.     

Mapping the Spatial Variability of Plant Diversity in a Tropical Forest: Comparison of Spatial Interpolation Methods

Knowledge of the spatial distribution of plant species is essential to conservation and forest managers in order to identify high priority areas such as vulnerable species and habitats, and designate areas for reserves, refuges and other protected areas. A reliable map of the diversity of plant species over the landscape is an invaluable tool for such purposes. In this study, the number of species, the exponent Shannon and the reciprocal Simpson indices, calculated from 141 quadrat sites sampled in a tropical forest were used to compare the performance of several spatial interpolation techniques used to prepare a map of plant diversity, starting from sample (point) data over the landscape. Means of mapped classes, inverse distance functions, kriging and co-kriging, both, applied over the entire studied landscape and also applied within vegetation classes, were the procedures compared. Significant differences in plant diversity indices between classes demonstrated the usefulness of boundaries between vegetation types, mapped through satellite image classification, in stratifying the variability of plant diversity over the landscape. These mapped classes, improved the accuracy of the interpolation methods when they were used as prior information for stratification of the area. Spatial interpolation by co-kriging performed among the poorest interpolators due to the poor correlation between the plant diversity variables and vegetation indices computed by remote sensing and used as covariables. This indicated that the latter are not suitable covariates of plant diversity indices. Finally, a within-class kriging interpolator yielded the most accurate estimates of plant diversity values. This interpolator not only provided the most accurate estimates by accounting for the indices' intra-class variability, but also provided additional useful interpretations of the structure of spatial variability of diversity values through the interpretation of their semi-variograms. This additional role was found very useful in aiding decisions in conservation planning.     

Reducing external costs of nitrogen pollution by relocation of pig production between regions in the European Union

This paper tests the hypothesis that relocation of pig production within the EU27 can reduce the external costs of nitrogen (N) pollution. The external cost of pollution by ammonia and nitrate from agriculture in the European Union (EU27) in 2008 was estimated at 61–215 billion € (0.5 to 1.8% of the GDP). Per capita it ranged from more than 1000 € in north-west EU27 to 50 € in Romania. The average contribution of pig production was 15%. Using provincial data (224 NUTS2 regions in EU27), the potential reduction of external N cost by relocation of pig production was estimated at 14 billion € (10% of the total). Regions most eligible for decreasing the pig stock were in western Germany, Flemish region, Denmark, the Netherlands and Bretagne, while Romania is most eligible for increasing pig production. Relocating 20 million pigs (13% of the total EU stock) decreased average external costs per capita from 900 to 785 € in the 13 NUTS2 regions where pigs were removed and increased from 69 to 107 € in 11 regions receiving pigs. A second alternative configuration of pig production was targeted at reducing exceedance of critical N deposition and closing regional nutrient cycles. This configuration relocates pigs within Germany and France, for example from Bretagne to Northern France and from Weser-Ems to Oberbayern. However, total external cost increases due to an increase of health impacts, unless when combined with implementation of best N management practices. Relocation of the pig industry in the EU27 will meet many socio-economic barriers and realisation requires new policy incentives.