Long-term trends in mercury and PCB congener concentrations in gannet (Morus bassanus) eggs in Britain

Gannet (Morus bassanus) eggs from Bass Rock (North Sea) and Ailsa Craig (eastern Atlantic) were monitored for PCB congeners (1990-2004) and total mercury (1974-2004). Congener profiles for both colonies were dominated by PCBs 153, 138, 180, 118 and 170. All declined in concentration at Ailsa Craig but some (153, 170, 180) remained stable or increased slightly at Bass Rock. Egg congener concentrations at Bass Rock were typically 10-fold higher than at Ailsa Craig by 2002, and Principal Component Analysis indicated that colony differences were driven by the dominant congeners. Egg mercury concentrations were significantly lower at Bass Rock than at Ailsa Craig and temporal trends differed, there being a significant decline at Ailsa Craig but a marginal increase at Bass Rock. Our results suggest there may be differences in contamination between the eastern Atlantic and North Sea and/or there are colony differences in prey selection and associated contaminant loads.     

Development and Analysis of Oxygen-Sensing Probes for In Situ Monitoring of Unsaturated Solid-State Biodegradation Processes

ABSTRACT

Oxygen (O₂) sensors have been developed for in situ measurement of O₂ in high-solids degradation processes. The O₂ sensor has been shown to withstand the corrosive environment of the biodegradation process with high humidity and temperatures exceeding 60 ^oC. Calibration tests prior to and after in situ operation showed the sensor to perform accurately and reproducibly after 71 days of in situ operation.

A linear relationship between O₂-sensor output and water vapor pressure was confirmed through calibration experiments. To compensate for the effect of water vapor pressure on O₂-sensor measurements, O₂ concentration was expressed on a dry air basis using the confirmed linear relationship. In situ O₂-sensor output expressed on a dry air basis was found to follow trends of gas samples analyzed by gas chromatography with good agreement.     

2,4,6-Trinitrotoluene mineralization and bacterial production rates of natural microbial assemblages from coastal sediments

The nitrogenous energetic constituent, 2,4,6-Trinitrotoluene (TNT), is widely reported to be resistant to bacterial mineralization (conversion to CO₂); however, these studies primarily involve bacterial isolates from freshwater where bacterial production is typically limited by phosphorus. This study involved six surveys of coastal waters adjacent to three biome types: temperate broadleaf, northern coniferous, and tropical. Capacity to catabolize and mineralize TNT ring carbon to CO₂ was a common feature of natural sediment assemblages from these coastal environments (ranging to 270+/−38 μg C kg⁻¹ d⁻¹). More importantly, these mineralization rates comprised a significant proportion of total heterotrophic production. The finding that most natural assemblages surveyed from these ecosystems can mineralize TNT ring carbon to CO₂ is consistent with recent reports that assemblage components can incorporate TNT ring carbon into bacterial biomass. These data counter the widely held contention that TNT is recalcitrant to bacterial catabolism of the ring carbon in natural environments.     

The social viability and environmental sustainability of direct action land reform settlements in the Amazon

State-led agrarian reform (SLAR) settlements established in the Amazon in the 1970s led to environmental degradation and mixed socioeconomic outcomes. More recently, direct-action land reform (DALR) settlements have proliferated, which are leading to new forest clearing in the name of agrarian reform. The emergence of DALR begs questions about social and environmental outcomes in recent Amazon settlements. This paper compares DALR settlements in two different regions of the eastern Amazon: the South of Pará and the Transamazon. Analysis of household survey data shows that DALR settlements in the two study areas differ substantially in terms of their histories of formation and regional contexts. However, social and environmental outcomes do not always differ among the two study areas, which in turn resemble older SLAR settlements.     

Soil erosion and risk-assessment for on- and off-farm impacts: A test case using the Midhurst area,West Sussex,UK

Soil erosion on agricultural land is a growing problem in Western Europe and constitutes a threat to soil quality and to the ability of soils to provide environmental services. The off-site impacts of runoff and eroded soil, principally eutrophication of water bodies, sedimentation of gravel-bedded rivers, loss of reservoir capacity, muddy flooding of roads and communities, are increasingly recognised and costed. The shift of funding in the European Union (EU) from production-related to avoidance of pollution and landscape protection, raises issues of cross-compliance: public support for agriculture has to be seen to give value-for-money. In this context risk-assessment procedures have been introduced to help farmers recognise sites where either certain crops should not be grown or anti-erosion measures are required. In England, Defra [Defra, 2005a. Controlling Soil Erosion: a Manual for the Assessment and Management of Agricultural Land at Risk of Water Erosion in Lowland England. Revised September 2005. Department for Environment, Food and Rural Affairs, London] sets out a system of risk-assessment, including ranking of crops susceptible to erosion and anti-erosion measures, that may be selected. We assess this system using field data for an area of erodible soils in the Rother valley, Sussex. The Defra approach correctly identifies most at-risk fields and, taken together with land-use maps, allows non-compliance with advice to be highlighted. We suggest a simple extension to the system which would further identify at-risk fields in terms of possible damage to roads and rivers from muddy runoff. The increased risk of erosion in the study area is associated with certain crops: potatoes, winter cereals, maize and grazed turnips and seems unlikely to be the result of changes in rainfall which over the last 130 years are minimal. We have not evaluated proposed anti-erosion measures in the area because few have been put into practice. The European Water Framework Directive will increasingly focus attention on agricultural fields as a source of river pollution. Assessing the risk of erosion and the need for field testing of suggested approaches, are not simply issues for the EU, but for the management of global agricultural systems.     

Fluorescent Tracer Studies of Pollutant Transport in the San Francisco Bay Area

To simulate the transport and diffusion of airborne contaminants across a metropolitan region, point-source releases of fluorescent tracer material were made near various urban centers and some 50 samplers were arrayed in expected downwind directions. The effects of land-water, hill-valley, and urban-rural differences on airflow and diffusion were observed in their existing interrelationships during these experiments. Since the tracer could be assessed with high sensitivity over great distances, tracer results provided a quantitative indicator of pollutant dispersion across an extensive metropolitan complex.

From July 1967 through June 1968, the test series included typical seasonal weather patterns, with emphasis on those conducive to the travel and accumulation of pollutants. In each test about 15 kilograms of tracer material were released during two-hour periods, and significant dosages were found at downwind distances up to 80 kilometers. All tests were conducted during daylight hours, to coincide better with the oxidant-type pollution important in this region.

Dispersion characteristics showed much greater complexity than predictable from classical models, thus limiting the applicability of such models in this region. Built-up urban areas increased the initial dispersion rates of tracer clouds, and travel over water tended to decrease them. Hilly terrain resulted in increased dispersion, but channeling associated with such terrain caused locally higher concentrations. The complex horizontal dosage patterns obtained did confirm previously observed airflow patterns as aids in predicting pollutant distributions.     

Removal of SO2 From Flue Gases Using Carbon at Elevated Temperatures

The interaction of a typical flue gas with active charcoal and bituminous coal char at temperatures between 600 and 800°C and atmospheric pressure has been studied. The SO₂ in the flue gas interacts with the carbon to form primarily H₂S, COS, and a carbon-sulfur surface complex. H₂S and COS break through the carbon bed much in advance of SO₂. At 800°C, sulfur retention on the bed exceeds at least 11% before SO₂ breakthrough occurs. The reaction of H₂S and COS with O₂ over active charcoal at 100–140°C to produce sulfur, which deposits on the carbon, has also been studied and found to be feasible. As a result of this study, a new process is outlined for the removal of SO₂ from flue gas, with the ultimate conversion     

ESP Performance Capability and Utilization: Past and Future

The following paper was presented by Alan B. Walker at the International Conference on Electrostatic Precipitation held in Monterey, California, October 14–16, 1981. Mr. Walker’s candid remarks were part of the opening session on “Electrostatic Precipitation Today.” The proceedings of this outstanding conference will be published by the Air Pollution Control Association.     

Building resilience and adaptation to manage Arctic change

Unprecedented global changes caused by human actions challenge society's ability to sustain the desirable features of our planet. This requires proactive management of change to foster both resilience (sustaining those attributes that are important to society in the face of change) and adaptation (developing new socioecological configurations that function effectively under new conditions). The Arctic may be one of the last remaining opportunities to plan for change in a spatially extensive region where many of the ancestral ecological and social processes and feedbacks are still intact. If the feasibility of this strategy can be demonstrated in the Arctic, our improved understanding of the dynamics of change can be applied to regions with greater human modification. Conditions may now be ideal to implement policies to manage Arctic change because recent studies provide the essential scientific understanding, appropriate international institutions are in place, and Arctic nations have the wealth to institute necessary changes, if they choose to do so.