ASSESSING SOLAR PHOTOVOLTAIC ENERGY SYSTEMS FOR CROP IRRIGATION1

ABSTRACT: An economic analysis of the profitability of adopting solar photovoltaic energy systems for crop irrigation is undertaken. The economic, technological, and political uncertainties surrounding adoption are discussed with reference to their impact on anticipated profitability. On the assumption that the costs of producing photovoltaic modules follows a learning curve characteristic of other inventions, solar systems are likely to be viable for irrigation in some states by mid to late 1980s. A field test in Nebraska is described.     

REVIEW OF LAKE RESTORATION PROCEDURES1

ABSTRACT Relevant information on the restoration of lakes is presented. The restoration procedures considered are applicable to the water, the bottom sediments, and aquatic plant improvement. A summary of thirteen (13) suggested methods of restoration are reviewed.     

Uptake rates of thorium progeny in a semiarid environment

The release rates and transformation processes that influence the mobility, biological uptake, and transfer of radionuclides are essential to the assessment of the health effects in the food chain and ecosystem. This study examined concentrations of 222Th in both soil and vegetation at a closed military training site, Kirtland Air Force Base (KAFB), New Mexico. Brazilian sludge was intentionally introduced into the topsoil in the early 1960s to simulate nuclear weapon accidents. Soil (60) and vegetation (120) samples were collected from 1996 to 2000 and analyzed for radionuclides and progeny. High-resolution gamma-ray spectroscopy was used to determine radionuclide activities. The results indicate that the thorium progeny were the predominant contaminant in soil and vegetation. Concentration ratios (CRs) were calculated based on actinium levels.     

Atmospheric particulate matter and polycyclic aromatic hydrocarbons for PM10 and size-segregated samples in Bangkok

Air samples of particulate matter (PM) with an aerodynamic diameter less than 10 microm (PM10) were collected from six sites in Bangkok, Thailand, using high-volume air samplers. Daily samples were taken at intervals of 12 days from November 1999 to November 2000. Size-selected sampling using a multislit Andersen size-fractionated cascade impactor was undertaken at one site in central Bangkok to identify particulate size distribution. The annual average PM10 concentration at all six sites exceeded the Thailand National Ambient Air Quality Standard (NAAQS) of 50 microg/m3. The daily PM10 concentrations at heavy traffic roadside areas ranged between 30 and 160 microg/m3. The highest PM10 level occurred during the winter period (November-February), which is the dry season. From our results, which are based on a 1-yr survey, it can be observed that the particulate concentrations are associated with traffic volumes and seasonal factors (temperature and rainfall). The relative importance of size fractions in contributing to PM load is presented and discussed. Twenty polycyclic aromatic hydrocarbons (PAHs) associated with PM have been identified and quantified. The summed PAHs based on the 20 species had an average concentration of 60 ng/m3. Benzo(e)pyrene, indeno(123cd)pyrene, and benzo(ghi)perylene were the major compounds with average concentrations of 8, 10, and 13 ng/m3, respectively. Results indicate that more than 97% of PAHs were found in the small particulate size range of <0.95 microm.     

Interacting effects of ambient light and plumage color patterns in displaying Wire-tailed Manakins (Aves,Pipridae)

Sending color signals to conspecifics may attract predators, leading to opposing selection pressures on the evolution of signal expression and display behavior in animals. The costs of signaling can be reduced, however, because conspicuousness is the combined result of the reflectance spectra of the displayer's color pattern and the spectra of ambient light illuminating the animal. Changes in ambient light can alter conspicuousness, even when chemical and structural color-generating mechanisms remain constant, potentially allowing animals to display their colors most fully in light environments where the benefits are greatest relative to the costs. Using spectroradiometric methods, we determined how light habitat use affects conspicuousness in adult males of the Wire-tailed Manakin Pipra filicauda, a lekking bird species with vivid plumage colors. We studied three aspects of visibility, including properties of the entire color pattern, visual contrast within an individual's plumage and a bird's contrast relative to its visual background. Wire-tailed Manakins usually displayed in forest shade environments, which reduced their conspicuousness at larger viewing distances, while maximizing visual contrast within the plumage color pattern at close viewing distances. Compared to sunspots, ambient light in forest shade reduces the contrast of individual bird colors with the background at close viewing distance. However, background contrast of individual bird colors in the shade was still relatively higher during sunny than during cloudy weather which may explain why males were more active when the sun was not blocked by clouds. Assuming that the visual perceptions of predators and other manakins do not differ from the reflectance patterns we measured, Wire-tailed manakins tend to display in light environments that reduce the conflicts between avoiding long distance detection by predators and displaying conspicuous color signals to visiting females.     

14C-Photosynthesis of Phytoplankton in an Oligotrophic Alpine Lake (Traunsee,Austria) and its Response to Turbidity Caused by Industrial Tailings

The influence of industrial tailings on the biological integrity of the phytoplankton was assessed from annual measurements of photosynthetic rates in the alpine lake Traunsee. The mean annual integral production of 21 mmol C m^-2 d^-1 corresponded to the oligotrophic nature of the lake. Effects of effluents were tested by comparing photosynthesis at a station close to the industrial outlet (EB) and at a reference site with a maximum depth of 190 m (VI). Between-site optical properties (vertical attenuation coefficient, euphotic depth) were statistically significant different. The euphotic zone at the impacted station was on average 2 m shallower than at the reference site, owing to turbidity emanating from the industrial plant. The adaptation to low light intensities by the algal community at this station was evident from a high maximum light utilisation coefficient (^* at low light saturation (E _K). Algae at the deep reference site were photosynthetically less efficient but adapted to high light intensities. Photosynthetic adaptation to different light climates in the euphotic zone without significant quantitative biomass alterations at the impacted site gave a clear signature of biological integrity of the phytoplankton in the oligotrophic Traunsee.     

Environmental evaluation of subdivision site developments

An environmental evaluation was performed at 16 subdivision sites within four communities in east-central Michigan. The primary objective was to evaluate the fit between environmental ordinances and the physical/environmental conditions to which they were applied. An environmental response index was developed with indicators to assess water, soil, slope, development density, roads, vegetation, and ecology. Water-related indicators achieved the highest scores, while soil-related indicators scored the poorest, with generally poor performance across all indicators. The poor performance indicates there are problems in the ability of environmental ordinances developed at broader jurisdictional scales (e.g., the state) to address the existing environmental conditions at smaller geographic scales (subdivisions within communities). Two key problems include the lack of scientific specificity in the broader state-level ordinances and the lack of local expertise and/or resources to monitor the environment.     

Accumulation of Heavy Metals by in vitro cultures of plants

The aim of the project is to study heavy metals accumulation by the selected plants in both laboratory and field conditions. Within the experiments the aspen (Populus tremula × tremuloides), sunflower (Helianthus annuus) and corn (Zea mays) plants were studied. The reasons for this selection were: a fast growth of these plants, an accumulation capacity and an ability to survive in different types of soils. The study was carried out on the aspen plantlets grown in vitro. The plants were exposed to the aqueous solutions having concentrations 0.1 mM, 0.5 mM of Pb²⁺ or Ni²⁺, respectively. The accumulation capacityfor aspen, was about 70% of Pb²⁺ originally present in the solution. The starting concentration of Pb²⁺ (0.5 mM) exhibited no negative impact on the growth. Besides in vitro expositions, a pilot-scale phytoremediation experiment was carried out at the polluted industrial area (Zn – 75000 mg/kg), (Pb – 16000 mg/kg), (Cr – 590 mg/kg), (Cd – 90 mg/kg) and (Cu – 1700 mg/kg).     

Chemical oxidation of tetrachloroethene in a fractured saprolite/bedrock aquifer

Two chemical oxidizers, Fenton's Reagent (FR) and sodium permanganate (NaMnO₄), were used to remediate groundwater contaminated by tetrachloroethene (PCE) in a fractured saprolite and bedrock aquifer in Rockville, Maryland. Initial PCE concentrations ranged from 11 to 25,000 μg/L, averaging 8,684 μg/L in March 2000. A total of 28,256 pounds of hydrogen peroxide (as 35 percent solution) and iron catalyst were injected during the FR treatment program. The FR failed to achieve the desired clean‐up goal, after which 11,114 pounds of NaMnO₄ (as 40 percent solution) were diluted to a 20 percent solution and injected into the aquifer. An additional 855 pounds of dilute NaMnO₄ was later injected, which ultimately reduced the original PCE mass by an estimated 95 percent through November 2001. © 2003 Wiley Periodicals, Inc.     

Air Quality Management in UK Local Authorities: Public Understanding and Participation

Science and technology are an integral part of informing public policy on air pollution and transport management. Expectations of science and technology by society and their use by air quality policy makers has led to increasing reliance upon this evidence to promote health and well-being. This can be seen, for example, in the setting of the UK national objectives for air pollutants based on exposure and health effects. This paper addresses three questions. It assesses, through the use of focus groups, the public perceptions of air pollution and the atmospheric dispersion model output from the Atmospheric Dispersion Modelling System-Urban. Then it assesses their understanding of this information and its current presentation to the layperson. Finally, it assesses how their perceptions and understanding influence their solutions to local air quality management in the London Borough of Camden. The results show that participants in the study struggled with the concept of air pollution outside their sphere of experience, and they did not understand the scientific basis or modelling used to inform local policy. This is partly a result of the way this information is presented. They did not relate the technological evidence to their opinions of acceptable solutions or they expressed reluctance to suggest specific options. It is proposed that a well-informed public would make comprehensive decisions on air quality based upon a broader range of factors, incorporating the scientific reasoning and technological information as well as emotive and socio-economic factors. A balance between science and technological understanding with the validity of local expertise will improve air quality policy making to the greater satisfaction of all stakeholders.