In situ chemical oxidation: Lessons learned at multiple sites

This paper compiles a detailed set of in situ chemical oxidation (ISCO) lessons learned pertaining to design, execution, and safety based on global experiences over the last 20 years. While the benefits of a “correct” application are known (e.g., cost effectiveness, speed, permanence of treatment), history also provides examples of a variety of “incorrect” applications. These provide an opportunity to highlight recurring themes that resulted in failures. ISCO is, and will continue to provide, an important remedial tool for site remediation, particularly as a component of a multifaceted approach for addressing large and complex sites. Future success, however, requires an objective understanding of both the benefits and the limitations of the technology. The ability to learn from the mistakes of the past provides an opportunity to eliminate, or at least minimize, them in the future. Over the last 25 years of ISCO application, process understanding and knowledge have improved and evolved. This paper combines a thorough discussion of lessons learned through decades of ISCO implementation throughout all aspects of ISCO projects with an analysis of changes to the ISCO remediation market. By discussing the interplay of these two themes and providing recommendations from collective lessons learned, we hope to improve the future of safe, cost‐effective, and successful applications of ISCO.     

Effects of law enforcement and community outreach on mammal diversity in a biodiversity hotspot

Management activities such as law enforcement and community outreach are thought to affect conservation outcomes in protected areas, but their importance relative to intrinsic environmental characteristics of the parks and extrinsic human pressures surrounding the parks have not been explored. Furthermore, it is not clear which is more related to conservation outcomes—the management itself or local people's perceptions of the management. We measured objective (reports by park staff) and subjective (reports by local people) levels of community outreach and law enforcement based on responses to 374 questionnaires. We estimated mammal abundance and diversity of 6 protected areas based on data from 115 camera traps in Xishuangbanna, southwest China, a biodiversity hotspot with high hunting and land-conversion pressures. We then examined correlations among them and found that local people's perception of law enforcement was positively related to the local abundance of 2 large, hunted species, wild boar (Sus scrofa) (β = 15.22) and muntjac (Muntiacus vaginalis) (β = 14.82), but not related to the abundance of smaller mammals or to objective levels of enforcement. The subjective frequency of outreach by park staff to local communities (β = 3.42) and park size (β = 3.28) were significantly and positively related to mammal species richness, whereas elevation, human population density, and subjective frequency of law enforcement were not. We could not conclude that community outreach and law enforcement were directly causing increased mammal abundance and diversity. Nevertheless, the patterns we detected are some of the first empirical evidence consistent with the idea that biodiversity in protected areas may be more positively and strongly related to local perceptions of the intensity of park management than to either intrinsic (e.g., elevation, park size) or extrinsic (e.g., human population density) environmental factors.     

Understanding the distribution of bushmeat hunting effort across landscapes by testing hypotheses about human foraging

Mitigating the massive impacts of defaunation on natural ecosystems requires understanding and predicting hunting effort across the landscape. But such understanding has been hindered by the difficulty of assessing the movement patterns of hunters in thick forests and across complex terrain. We statistically tested hypotheses about the spatial distribution of hunting with circuit theory and structural equation models. We used a data set of >7000 known kill locations in Guyana and hunter movement models to test these methods. Comparing models with different resistance layers (i.e., different estimates of how terrain and land cover influence human movement speed) showed that rivers, on average, limited movement rather than serving as transport arteries. Moreover, far more kills occurred close to villages than in remote areas. This, combined with the lack of support for structural equation models that included latent terms for prey depletion driven by past overhunting, suggests that kill locations in this system tended to be driven by where hunters were currently foraging rather than by influences of historical harvest. These analyses are generalizable to a variety of ecosystems, species, and data types, providing a powerful way of enhancing maps and predictions of hunting effort across complex landscapes.     

A free-enzyme catalyst for the bioremediation of environmental atrazine contamination

Herbicide contamination from agriculture is a major issue worldwide, and has been identified as a threat to freshwater and marine environments in the Great Barrier Reef World Heritage Area in Australia. The triazine herbicides are of particular concern because of potential adverse effects, both on photosynthetic organisms and upon vertebrate development. To date a number of bioremediation strategies have been proposed for triazine herbicides, but are unlikely to be implemented due to their reliance upon the release of genetically modified organisms. We propose an alternative strategy using a free-enzyme bioremediant, which is unconstrained by the issues surrounding the use of live organisms. Here we report an initial field trial with an enzyme-based product, demonstrating that the technology is technically capable of remediating water bodies contaminated with the most common triazine herbicide, atrazine.     

Some toxicological aspects op methamidophos exposure in mice 1

Abstract

Cholinesterase activity in the brain, RBC and plasma of Swiss mice was determined following different routes of administration of methamidophos. Continuous feeding with the insecticide caused a progressive inhibition of both plasma‐ and erythrocyte enzymes. The effect of methamidophos was more pronounced when applied in diet than when administered dermally or intraperitoneally. Following a single injection (i.p.) of methamidophos, the brain enzyme showed maximum inhibition 24 hr following treatment. At the appearance of tremors, the plasma and RBC‐enzymes showed considerable inhibition, the former being more inhibited. The plasma enzyme appears to be the most sensitive enzyme and may be taken as a suitable index for exposure to methamidophos.     

Assessment of the Water Quality and Ecosystem Health of the Great Barrier Reef (Australia): Conceptual Models

Run-off containing increased concentrations of sediment, nutrients, and pesticides from land-based anthropogenic activities is a significant influence on water quality and the ecologic conditions of nearshore areas of the Great Barrier Reef World Heritage Area, Australia. The potential and actual impacts of increased pollutant concentrations range from bioaccumulation of contaminants and decreased photosynthetic capacity to major shifts in community structure and health of mangrove, coral reef, and seagrass ecosystems. A detailed conceptual model underpins and illustrates the links between the main anthropogenic pressures or threats (dry-land cattle grazing and intensive sugar cane cropping) and the production of key contaminants or stressors of Great Barrier Reef water quality. The conceptual model also includes longer-term threats to Great Barrier Reef water quality and ecosystem health, such as global climate change, that will potentially confound direct model interrelationships. The model recognises that system-specific attributes, such as monsoonal wind direction, rainfall intensity, and flood plume residence times, will act as system filters to modify the effects of any water-quality system stressor. The model also summarises key ecosystem responses in ecosystem health that can be monitored through indicators at catchment, riverine, and marine scales. Selected indicators include riverine and marine water quality, inshore coral reef and seagrass status, and biota pollutant burdens. These indicators have been adopted as components of a long-term monitoring program to enable assessment of the effectiveness of change in catchment-management practices in improving Great Barrier Reef (and adjacent catchment) water quality under the Queensland and Australian Governments’ Reef Water Quality Protection Plan.     

VILLAGE DEMONSTRATION OF BIOGAS TECHNOLOGY: AN EGYPTIAN CASE STUDY

Within the context of biogas R & D and demonstration project undertaken by the Egyptian National Resarch Centre, village demonstrations are of paramount importance. In this paper, a case study of a pioneering village demonstration is presented. Based on a preliminary sociological survey, “Al Manawat” - a traditional Egyptian village was selected for the first demonstration. After a short orientation phase through which the biogas technology was introduced to a group of village representatives, a family was selected to conduct the demonstration experiment. Concomitant with the family energy requirements, availability of digester feed materials, site characteristics and other relevant factors, a family-size unit of a modified Indian type was designed and erected by the side of the farmer's house. The digester effective volume is 9 cu.m. and is connected to both a latrine and animal shed. The unit has been successfully operated since May 1981. The highlights of the construction stage as well as the unit performance characteristics are discussed. A preliminary techno-economic appraisal is also outlined. Finally, social impacts are assessed. Initial results indicate that under the Egyptian village conditions, and particularly with the heavily subsidized fuel prices, the high saving in manure transport attained through the introduction of the biogas unit, appears to be the main benefit from the farmer's point of view. Dans le cadre de la recherche et du développement du gaz de fermentation et d'un projet pilote entrepris par le Centre national de recherche égyptien, les démonstrations faites dans les villages occupent une place prépondérante. Dans cet article, l'auteur présente le cas-type d'une démonstration pilote faite dans un village. En se basant sur une enquêue sociologique préliminaire, “Al Manawat”, qui est un village égyptien traditionnel, a été choisi comme lieu de la première démonstration. Après une courte phase d'orientation au cours de laquelle le technologie du gaz de fermentation a été présentée à un groupe de notables du village, on a choisi une famille pour effectuer la démonstration expérimentale. En même temps que l'on étudiait les besoins énergétiques de cette famille, la disponibilité de matières de base de fermentation, les caractéristiques de l'emplacement et tous autres facteurs pertinents, une unité familiale de type indien modifié a été con?ue et érigée à côté de la ferme. Le composteur, d'un volume utile de matières premières de 9 m³, est relié à la fois aux latrines et à l‘étable. Cette unité fonctionne avec satisfaction depuis le mois de mai 1981. L'article met en avant les points essentiels des étapes de la construction et les caractéristiques de rendement de l'unité de fermentation. Il esquisse une évaluation technico-économique préliminaire et fait l'estimation des retombées sociales. Les premiers résultats montrent que, dans le cadre du village égyptien et particulièrement du fait que les prix du fuel sont largement subventionnés, les économies importantes réalisées dans le transport du fumier grâce á l'introduction de l'unité de fermentation semblent étre, du point de vue du fermier, le bénéfice principal. Dentro del contexto del proyecto de I & D y demostración realizado por el Centro de Investigación Nacional de Egipto, la demostración en los villorrios es de suma importancia. Este artículo presenta un caso pionero de este tipo. Basado en encuestas sociológicas, un villorrio tradicional de Egipto, “Al Manawat” fue selectiondo para la primera demostración. Después de una fase corta de orientación en la que se introdujo la tecnologia del biogás a los representantes del villorrio, se seleccionó una familia con cuya colaboración se Ilevaria a cabo el experimento. Teniendo en cuenta las necesidades de energia de la familia, la disponibilidad de materia prima para el digestor, las caracter ísticas del lugar y otros factores importantes, se diseñó y construyó un digestor de tamaño familiar, usando un modelo Indio, al lado de la casa de la familia. El volumen efectivo del digestor es 9 metros cúbicos y está conectado a la letrina y al corral de animales. La unidad está funcionando con éxito desde Mayo de 1981. Se discuten aspectos de la etapa de construcción y las características de operación. Se hace también una evaluación técnico-económica preliminar. Finalmente se evalúa el impacto social de la experiencia. Los resultados indican que en las condiciones de los villorrios Egipcios, especialmente en condiciones de precios de combustibles altamente sub-sidiados, los grandes ahorros en el transporte de abono debido a la introducción del digestor de biogas parece ser el mayor beneficio desde el punto de vista de la familia.     

Effects of mercury graded doses on redox status,metallothionein levels and genotoxicity in the intestine of sea cucumber Holothuria forskali

Mercury (Hg) is a ubiquitous and a major environmental metal pollutant in the aquatic ecosystem. The present study was performed to evaluate the effect of mercury graded doses exposure on oxidative stress, redox status, metallothionein levels and genotoxicity in the intestine of sea cucumber Holothuria forskali. Specimens were exposed for 96?h to three concentrations of Hg (40, 80 and 160?µg/L). Exposure of H. forskali to Hg promoted oxidative stress with an increase in malondialdehyde (MDA), protein carbonyl (PCO) and advanced oxidation protein products (AOPP) levels. An increase of glutathione (GSH), vitamin C (ViteC) and non-protein thiols (NPSH) contents was also observed. Additionally, antioxidant activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) increased especially with the highest doses of Hg indicating a great defense of the antioxidant system. Our investigation revealed an increase in total Metallothionein (MT) content which was more pronounced at the sharpest concentrations of Hg. A significant decline of AChE activity was also observed. In the intestine of Hg-treated H. forskali genotoxicity was confirmed by DNA degradation.