A Case Study of the Beneficial Reuse of Treated Groundwater

The future disposal of treated groundwater at the former Nebraska Ordnance Plant (NOP) Superfund site has been a topic of interest to the local property owners, the U.S. Army Corps of Engineers, and the local regulatory agencies. The Record of Decision for the site includes the extraction, treatment, and disposal of almost 3,000 gpm of groundwater with an estimated restoration time period exceeding 100 years. Interest from property owners and the Nebraska agency charged with regulating groundwater supply prompted the Corps of Engineers to consider several strategies for beneficially reusing the treated water. Alternatives included the establishment of a rural water district or local distribution system; delivery of the water to the municipal supply system of Lincoln, Nebraska, andsol;or other nearby municipalities; and consideration of innovative remedial technologies to reduce the quantity of treated water requiring disposal. The selected disposal plan consists of providing treated groundwater to interested parties for agricultural use with excess treated groundwater discharged to two streams. Multiple feasibility studies were generated, public input was solicited, and interagency agreements were executed during the course of the project. The remediation project is currently being constructed, and at least one property owner has constructed a new center‐pivot irrigation system to use the treated groundwater. © 2001 John Wiley & Sons.     

Factors affecting the direct mineralization of CO2 with olivine

Olivine, one of the most abundant minerals existing in nature, is explored as a CO2 carbonation agent for direct carbonation of CO2 in flue gas. Olivine based CO2 capture is thermodynamically favorable and can form a stable carbonate for long-term storage. Experimental results have shown that water vapor plays an important role in improving CO2 carbonation rate and capacities. Other operation conditions including reaction temperature, initial CO2 concentration, residence time corresponding to the flow rate of CO2 gas stream, and water vapor concentration also considerably affect the performance of the technology.     

Feeding behavior in sexual and clonal strains of Poeciliopsis

Summary Sexual and clonal fish of the genus Poeciliopsis occur together in desert streams of Sonora, Mexico. Their coexistence has been explained in terms of niche partitioning for food and space. We examined predatory behavior that might influence niche relationships, and found significant differences among two coexisting sperm-dependent clonal strains and their two sexual progenitors. Handling time and prey manipulation of free-swimming (Artemia) and benthic (chironomid larvae) prey differed significantly among sexual and clonal strains. Analyses of gut contents from field-collected fish revealed that the laboratory estimates of predatory efficiency were related to their feeding behavior in nature. Behavior differences, such as those described herein, contribute to our understanding of the mechanisms of unisexual/bisexual coexistence in Poeciliopsis. Offprint requests to: R.C. Vrijenhoek     

Conservation Implications of Introduced Game Birds in High-Elevation Hawaiian Shrubland

The Ring-necked Pheasant ( Phasianus colchicus ) and the Chukar ( Alectoris chukar ) are the dominant avifauna in high-elevation shrubland (2070–3000 m) of Haleakala National Park, Maui, Hawaii. We studied the food habits, ecological niche, and effects of these alien game birds on the native biota in this Hawaiian ecosystem. Analyses of crop contents indicated that pheasant and Chukar consumed predominantly fruits of native, woody dicots (39% and 47% respectively) and leaves (29% and 24% respectively) and flower parts (12% and 17% respectively) of alien, herbaceous dicots. Both species generally selected food items according to their relative availability, although other factors influenced choice of certain items. Invertebrates were a minor component of the game-bird diet, suggesting that their impact on native invertebrate populations is minimal. Pheasant and Chukar occupy, at least partially, an ecological niche once held by now-extinct or rare birds, and they appear not to be significant competitors with the endangered Nene. The role of these alien birds in facilitating seed dispersal and germination of native plant species is beneficial in restoring degraded ecosystems.     

The Role of Fungal Symbioses in the Adaptation of Plants to High Stress Environments

All plants studied in natural ecosystemsare symbiotic with fungi that either resideentirely (endophytes) or partially(mycorrhizae) within plants. Thesesymbioses appear to adapt to biotic andabiotic stresses and may be responsible forthe survival of both plant hosts and fungalsymbionts in high stress habitats. Here wedescribe the role of symbiotic fungi inplant stress tolerance and present astrategy based on adaptive symbiosis topotentially mitigate the impacts of globalchange on plant communities.     

Continuous determination of fine particulate matter mass in the Salt Lake City Environmental Monitoring project: a comparison of real-time and conventional TEOM monitor results

Fine particulate matter (PM2.5) mass was determined on a continuous basis at the Salt Lake City Environmental Protection Agency Environmental Monitoring for Public Awareness and Community Tracking monitoring site in Salt Lake City, UT, using three different monitoring techniques. Hourly averaged PM2.5 mass data were collected during two sampling periods (summer 2000 and winter 2002) using a real-time total ambient mass sampler (RAMS), sample equilibration system (SES)-tapered element oscillating microbalance (TEOM), and conventional TEOM monitor. This paper compares the results obtained from the various monitoring systems, which differ in their treatment of semivolatile material (SVM; particle-bound water, semivolatile ammonium nitrate, and semivolatile organic compounds). PM2.5 mass results obtained by the RAMS were consistently higher than those obtained by the SES-TEOM and conventional TEOM monitors because of the RAMS ability to measure semivolatile ammonium nitrate and semivolatile organic material but not particle-bound water. The SES-TEOM monitoring system was able to account for an average of 28% of the SVM, whereas the conventional TEOM monitor loses essentially all of the SVM from the single filter during sampling. Occasional mass readings by the various TEOM monitors that are higher than RAMS results may reflect particle-bound water, which, under some conditions, is measured by the TEOM but not the RAMS.     

Methodology for siting ambient air monitors at the neighborhood scale

In siting a monitor to measure compliance with U.S. National Ambient Air Quality Standards (NAAQS) for particulate matter (PM), there is a need to characterize variations in PM concentration within a neighborhood-scale region to achieve monitor siting objectives. A simple methodology is provided here for the selection of a neighborhood-scale site for meeting either of the two objectives identified for PM monitoring. This methodology is based on analyzing middle-scale (from 100 to 500 m) data from within the area of interest. The required data can be obtained from widely available dispersion models and emissions databases. The performance of the siting methodology was evaluated in a neighborhood-scale field study conducted in Hudson County, NJ, to characterize the area's inhalable particulate (PM10) concentrations. Air monitors were located within a 2- by 2-km area in the vicinity of the Lincoln Tunnel entrance in Hudson County. Results indicate the siting methodology performed well, providing a positive relationship between the predicted concentration rank at each site and the actual rank experienced during the field study. Also discussed are factors that adversely affected the predictive capabilities of the model.     

Estimating uncertainties and uncertainty contributors of CMB PM2.5 source apportionment results

The chemical mass balance (CMB) model was applied for source apportionment of PM_2.5 in Atlanta in order to explore levels and causes of uncertainties in source contributions. Monte Carlo analysis with Latin hypercube sampling (MC-LHS) was performed to evaluate the source impact uncertainties and quantify how uncertainties in ambient measurement and source profile data affect results. In general, uncertainties in the source profile data contribute more to the final uncertainties in source apportionment results than do those in ambient measurement data. Uncertainty contribution estimates suggest that non-linear interactions among source profiles also affect the final uncertainties although their influence is typically less than uncertainties in source profile data.     

Impact of using prognostic and objective wind fields on the photochemical modeling of Athens, Greece

A three-dimensional Eulerian photochemical model is used to follow the dynamics of ozone, NO_x, and CO over the Athens area, for 25 May 1990, the day considered in the APSIS project. A unique aspect of this work lies in the study of the impacts of the wind field preparation methods on the concentrations predicted by the model. Three sets of wind fields are developed. The first one used is derived from a prognostic meteorological model. The second one is calculated from available wind observations using objective: methods. For these two cases, a previous day is simulated, using the same conditions, to develop preconditioned initial conditions for the following day. For the third simulation, again two days are simulated, this time using the observed winds for each of the two days modeled. The predictions using the prognostically derived and the objective analysis wind fields are significantly different, particularly for the primary pollutants. Comparing predictions to the observations did not favor any particular method of wind field preparation. In this case, when using the prognostically derived field, the simulations are very sensitive to boundary conditions. In contrast, when using the wind fields constructed by objective methods, the simulations became most sensitive to emissions and initial conditions. This comes directly from the different residence times in the domain, which are governed by the wind speed.