MODELING THE IMPACT OF MULTICOMPONENT VOCs ON GROUND WATER USING THE STEFAN‐MAXWELL EQUATION1

ABSTRACT: Computer programs that model the fate and transport of organic contaminants through porous media typically use Fick's first law to calculate vapor phase diffusion. Fick's first law, however, is limited to the case of a single, dilute species diffusing into a stagnant, high concentration, bulk vapor phase. When dealing with more than one diffusing species and at higher concentrations, the multicomponent coupling effects on vapor phase diffusion and advection of the various constituents become significant. VLEACH, a one‐dimensional finite difference model developed for the U.S. Environmental Protection Agency (USEPA), is typical of the models using Fick's first law to model vapor‐phase diffusion. The VLEACH model was modified to accommodate up to 10 components and to calculate the binary diffusion coefficients for each of the components based on molecular weight, molecular volume, temperature and pressure, and to address the coupling effects on multiple component vapor phase diffusion and its impact on ground water. The resulting model was renamed MC‐CHEMSOIL. At low vapor phase concentrations, MC‐CHEMSOIL predicts identical ground water impacts (dissolved phase loading) to those from VLEACH 2.2a. At higher vapor phase concentrations, however, the relative difference between the models exceeded 20 percent.     

IRRIGATOR INVOLVEMENT IN THE IMPLEMENTATION OF AGRICULTURAL NONPOINT SOURCE POLLUTION CONTROL PROGRAMS1

ABSTRACT: Recently, Congress designated irrigated agriculture under the “nonpoint source” category, covered by Section 208 of P.L. 92-500 and involves the use of “best management practices.” Generally, the most appropriate solutions for pollution abatement from irrigated agriculture involve the delivery and use of water rather than the treatment of irrigation return flows. 1. Technological alternatives should be utilized that are sensitive to local conditions and acceptable to the farmers. 2. Informational and educational programs to assist farm operators individually and collectively must be instituted prior to the start of the project; imaginatively conceived, and continuously modified and upgraded if motivation for change is to be encouraged. 3. Technical assistance personnel should be given short courses in skills needed for working effectively with irrigators. 4. Communication techniques used for working with farmers as individuals and groups should be designed into the implementation program and evaluated. 5. Credibility and trustworthiness of Federal and state agencies in the eyes of the irrigators provide the important final ingredient in effectively implementing change and reducing nonpoint source pollution from irrigated agriculture.     

The effects of pathway configuration, landmarks and stress on environmental cognition

The results of this study indicate that manipulations of the pathway grid configuration and landmark placement in a setting cause changes in environmental knowledge. These experimental manipulations were accomplished using a realistic, dynamic simulation technique at the Berkeley Environmental Simulation Laboratory. Measures of environmental knowledge include: memory for incidental information along the simulated urban route, accuracy of route maps, relocation memory for scenes along the route, and questionnaire measures. Data are also presented showing both positive and negative effects of stress from noise on the processes of environmental cognition.     

Community opinion concerning airport noise-abatement alternatives

In the present study we examined (1) community opinion of airport noise-abating alternatives and (2) the influence of perceived control on attitudes concerning noise-abatement policies and annoyance toward aircraft noise. We proposed that residents who perceive themselves as having little control over aircraft noise exposure would express higher levels of annoyance than residents who believe they have some degree of control. Furthermore, residents with low levels of perceived control would be less favorable toward proposed noise-abatement alternatives. Survey results collected from 239 households within the 65 CNEL contour of a community airport in Southern California support these hypotheses. Findings indicate strong public support for noise abatement and strong opposition to land-use alternatives. In addition, residents' perceptions of control in the airport planning and management process are significantly related to their annoyance with noise and their opinions about noise management policies.     

A box model for calculation of collective dose commitment from radioactive waterborne releases to the baltic sea

To meet the new regulations of maximum yearly releases from Swedish nuclear power plants issued by the Swedish National Radiation Protection Institute, and to make realistic calculations of collective dose commitment derived from radionuclides discharged to the Baltic Sea, a box model AQUAPATH-BALTIC has been developed. The model calculates radionuclide concentrations in 25 boxes for discharges into given compartments and takes into consideration the dispersion rates of the water masses, the sediment-water interaction and radioactive decay. The calculated concentrations in water and sediment at steady state are then used to evaluate individual and collective intakes of activity and external exposures. The radiation doses to the global population following discharges to the Baltic Sea are also calculated.     

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.     

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.     

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.