Influence of humic acid on the sorption of uranium(IV) to kaolin

Safety assessments for radioactive waste disposal require estimations of the migration of radionuclides in soils. The influence of humic acid (HA) on the sorption of uranium in its +4 oxidation state to kaolin has been examined from pH 4 to 8, with HA concentrations of 15–200 ppm. In the absence of HA, 20–40% of the U(IV) was in solution, with more sorption occurring at higher pH. The presence of HA solubilised up to 90% of the uranium with higher solubilities at higher HA concentrations and higher pH values. Uranium sorption was mapped against HA sorption, and it was found that there was a lower level of U(IV) sorption than can be accounted for by just measuring HA sorption. However, this effect got less marked as the pH rose. Sensitivity analysis indicated that the fraction of surface-bound HA is the controlling parameter for modelling in these systems.     

The National Forest and Local Agenda 21: An Experiment in Integrated Landscape Planning

The post-Rio environmental accord has offered new opportunities for landscape planning linking global concerns with Local Agenda 21 through concepts of sustainable development. This paper analyses the potential for integrated landscape planning by linking the aims of global sustainability with a major initiative of the UK Government, the National Forest located in the English Midlands. A common commitment to concepts of partnership and participation facilitated by local authorities can be found in the National Forest Strategy and in the principles of Local Agenda 21. Using case studies comparing local fora created to implement parts of the National Forest Strategy with focus groups formed to prepare Local Agenda 21 Action Plans, it is argued that a common consensus between these endeavours has not so far been achieved. Problems associated with the interpretation of national government policy guidance following the Earth Summit coupled with the constitution, membership and goals of specific groups are viewed as the primary reasons for conflict. These have implications for achieving compatibility between the Forest ideals and those enshrined in Local Agenda 21, particularly in localities where mineral exploitation and landfill are contentious planning concerns.     

The 1999 Fresno Particulate Matter Exposure Studies: Comparison of Community,Outdoor, and Residential PM Mass Measurements

ABSTRACT

Two collaborative studies have been conducted by the U.S. Environmental Protection Agency (EPA) National Exposure Research Laboratory (NERL) and National Health and Environmental Effects Research Laboratory to determine personal exposures and physiological responses to par-ticulate matter (PM) of elderly persons living in a retirement facility in Fresno, CA. Measurements of PM and other criteria air pollutants were made inside selected individual residences within the retirement facility and at a central outdoor site on the premises. In addition, personal PM exposure monitoring was conducted for a subset of the participants, and ambient PM monitoring data were available for comparison from the NERL PM research monitoring platform in central Fresno. Both a winter (February 1-28, 1999) and a spring (April 19-May 16, 1999) study were completed so that seasonal effects could be     

Injuries causing death: Their nature,external causes,and associated diseases

This article provides national data on the types of injuries reported on death certificates, the external causes of these injuries, and diseases that are frequently reported with them. Injuries were a factor in 11 % (213,366 deaths) of the deaths to residents of the United States in 1978. Of 11 broad categories of injuries, three (fractures, sprains, strains, and dislocations, intracranial injuries, and adverse effects) were mentioned on almost 50,000 deaths each. There was considerable variation in the distribution of injury types by age, sex, and race. The most notable example was fractures of the lower limb which were mentioned on 29% of the deaths involving an injury to 65 + year olds but no less than 5% of such deaths for all other age groups. For white females, the percentage with a fracture of the lower limb was 23 % compared to 12 % overall. In 25 % of the deaths involving an injury, the immediate cause was a motor vehicle accident. In 51 %, the immediate cause of the injury was a non-motor-vehicle accident. In 73 % of the deaths involving non-motor-vehicle accidents, disease conditions as well as injuries were a factor; and, 69% of the time, the disease condition was actually the underlying cause of the death with the injury being a contributing factor or complication. For example, over 14,000 deaths in 1978 involved a circulatory condition as the underlying cause of death which was complicated by an accidental fracture, sprain, or dislocation. Although diseases more often assumed the role of the underlying cause of death, they were also a nonunderlying cause in 24,000 non-motor-vehicle accident deaths. Over 12,000 of such deaths involved circulatory diseases.     

The risk assessment-policy gap: an example from the UK contaminated land regime

Risk-based regulation assumes that risk assessment can evaluate risks against policy objectives. However, policy goals are often ambiguous and require risk assessors to interpret them for use in risk assessment. This risk assessment-policy gap stems partly from normative and imprecise policy language but is rooted more fundamentally in society's uncertain expectations for the environment. Until this uncertainty is resolved, the democratic and regulatory effectiveness of risk regulation will be undermined by ad hoc policy decisions abdicated to risk assessors.     

Brood reduction in the American white pelican (Pelecanus erythrohynchos)

Summary American white pelicans (Pelecanus erythrorhynchos) breeding in colonies at East Shoal Lake, Manitoba, Canada exhibited a mean hatching asynchrony of 2.5 days in 2-egg clutches. This resulted in a size difference between chicks which facilitated sibling dominance, harassment and lack of food for the subordinate chick. Only one young survived per nest. In marked broods, the secondhatched chick survived in 20% of successful nests. Manipulated clutch sizes (1, 2 and 3 eggs or chicks per nest) revealed that the presence of a second chick contributes significantly to the reproductive success of the parents. Results support the hypothesis that the second egg functions as a form of insurance against early loss of the first egg or chick. The parents, by establishing hatching asynchrony, by nonintervention in sibling aggression, and by selectively feeding the dominant chick, maximize their chance of rearing the most viable young.     

Recovery from acidification in European surface waters: a view to the future

There is now overwhelming documentation of large-scale chemical recovery from surface water acidification in Europe, but to date there has been little documentation of biological recovery. Modelling studies based on current emission reduction plans in Europe indicate that there will be further chemical recovery. The uncertainties in these scenarios mainly relate to the future behavior of nitrogen in the ecosystem and the effects of climate change. Four major climate-related confounding factors that may influence the chemical and biological recovery process are: i) increased frequency and severity of sea-salt episodes; ii) increased frequency and severity of drought; iii) increased turnover of organic carbon; iv) increased mineralization of nitrogen. International cooperative work to abate acidification has so far been very successful, but there is still a long way to go, and many potential setbacks. It is essential that future development of water chemistry and aquatic biota in acidified waterbodies continue to be monitored in relation to further emission reductions of S and N and future effects of climate change.