Monitoring iodine-129 in air and milk samples collected near the Hanford Site: an investigation of historical iodine monitoring data

While other research has reported on the concentrations of (129)I in the environment surrounding active nuclear fuel reprocessing facilities, there is a shortage of information regarding how the concentrations change once facilities close. At the Hanford Site, the Plutonium-Uranium Extraction (PUREX) chemical separation plant was operating between 1983 and 1990, during which time (129)I concentrations in air and milk were measured. After the cessation of chemical processing, plant emissions decreased 2.5 orders of magnitude over an 8-year period. An evaluation of (129)I and (127)I concentration data in air and milk spanning the PUREX operation and post-closure period was conducted to compare the changes in environmental levels. Measured concentrations over the monitoring period were below the levels that could result in a potential annual human dose greater than 1 mSv. There was a measurable difference in the measured air concentrations of (129)I at different distances from the source, indicating a distinct Hanford fingerprint. Correlations between stack emissions of (129)I and concentrations in air and milk indicate that atmospheric emissions were the major source of (129)I measured in environmental samples. The measured concentrations during PUREX operations were similar to observations made around a fuel reprocessing plant in Germany. After the PUREX Plant stopped operating, (129)I concentration measurements made upwind of Hanford were similar to the results from Seville, Spain.     

Determination of chlorothalonil residues in coffee

Coffee beans were treated with the fungicide chlorothalonil (2,4,5,6‐tetrachloro‐1,3‐benzene‐dicarbonitrile) and the residues were determined by high‐performance liquid Chromatograph (HPLC). Several techniques including Soxhlet extraction (SE), microwave‐assisted extraction (MAE) and accelerated solvent extraction (ASE) were compared for the extraction of residues. A column clean‐up procedure was developed to remove the co‐extractives in the extract before HPLC analysis. The overall mean recoveries from extracts obtained by SE, MAE and ASE were 89.2 ±3.9, 88.4 ±1.9 and 82.8 ±0.3, respectively. The results show that MAE followed by HPLC is a viable alternative to the commonly used SE and gas Chromatographic analysis for the determination of chlorothalonil in coffee.     

Discounting for personal and social payments: Patience for others,impatience for ourselves

The market rate of return on private investment is often used as the discount rate when conducting cost-benefit analysis (CBA) of public projects. I argue that the decision to invest pits current consumption against future consumption, both of which accumulate to the private decision maker. Public projects, on the other hand, provide benefits that accrue to society in general. To examine the appropriateness of discount rates based on returns to private investment, this paper considers lab experiments designed to test whether individuals discount personal and social benefits at different rates. Personal benefits are captured through personal monetary payments, while social benefits are captured through anonymous donations to charitable organizations. I jointly elicit time and risk preferences and find that subjects discount charitable contributions at significantly lower rates than personal payments.     

Urban channel adjustments in a management context: an Australian example

The impact of urbanization on stream channels has been investigated in a range of areas; the degree and extent of the channel adjustments have been demonstrated; and for a few areas these characteristics have recently been placed into a spatial context. A method of rapid field survey for depicting the channel network of urban areas in terms of near natural, adjusted, and channelized systems is illustrated for the urban area of Armidale NSW, for which Armidale Dumaresq Council had prepared a stormwater management plan. Such a survey could enable channel characteristics and adjustments, as well as water quantity and quality, to be included in the management plan. Possible options for management to address are suggested for each of the channel categories. A channel classification system of the kind suggested can provide a basic complement for the further development of the stormwater management plan, can afford a basis for specifying management alternatives, and can be helpful in demonstrating the options offered for community consultation.     

Factors Affecting Future Emissions of Methane from Non Land Use Sources

Evidence from the atmosphere indicates that global emissions of methane may have been broadly constant since the early 1980s or growing only slowly. This suggests that whilst emissions from some sources may have increased with increased activity, emissions from other sources may have gone down. This is supported by evidence and analysis from the individual emission sectors which show declining emission rates in some cases. This paper reviews the factors that might affect emissions in the future from different sources and has been written as an aid to the development of new scenarios for greenhouse gas emission for the Intergovernmental Panel on Climate Change. The analysis indicates that there could be additional uncertainty in future emissions but that, overall, future emissions might plausibly be lower than previously projected.     

Spatial and temporal variability of the overall error of National Atmospheric Deposition Program measurements determined by the USGS collocated-sampler program, water years 1989-2001

Data from the U.S. Geological Survey (USGS) collocated-sampler program for the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) are used to estimate the overall error of NADP/NTN measurements. Absolute errors are estimated by comparison of paired measurements from collocated instruments. Spatial and temporal differences in absolute error were identified and are consistent with longitudinal distributions of NADP/NTN measurements and spatial differences in precipitation characteristics. The magnitude of error for calcium, magnesium, ammonium, nitrate, and sulfate concentrations, specific conductance, and sample volume is of minor environmental significance to data users. Data collected after a 1994 sample-handling protocol change are prone to less absolute error than data collected prior to 1994. Absolute errors are smaller during non-winter months than during winter months for selected constituents at sites where frozen precipitation is common. Minimum resolvable differences are estimated for different regions of the USA to aid spatial and temporal watershed analyses.     

Use of stream chemistry for monitoring acidic deposition effects in the Adirondack region of New York

Acid-neutralizing capacity (ANC) and pH were measured weekly from October 1991 through September 2001 in three streams in the western Adirondack Mountain region of New York to identify trends in stream chemistry that might be related to changes in acidic deposition. A decreasing trend in atmospheric deposition of SO4/2- was observed within the region over the 10-yr period, although most of the decrease occurred between 1991 and 1995. Both ANC and pH were inversely related to flow in all streams; therefore, a trend analysis was conducted on (i) the measured values of ANC and pH and (ii) the residuals of the concentration-discharge relations. In Buck Creek, ANC increased significantly (p < 0.05) over the 10 yr, but the residuals of ANC showed no trend (p > 0.10). In Bald Mountain Brook, ANC and residuals of ANC increased significantly (p < 0.01), although the trend was diatonic-a distinct decrease from 1991 to 1996 was followed by a distinct increase from 1996 to 2001. In Fly Pond outlet, ANC and residuals of ANC increased over the study period (p < 0.01), although the trend of the residuals resulted largely from an abrupt increase in 1997. In general, the trends observed in the three streams are similar to results presented for Adirondack lakes in a previous study, and are consistent with the declining trend in atmospheric deposition for this region, although the observed trends in ANC and pH in streams could not be directly attributed to the trends in acidic deposition.     

Understandings of Environmental Quality: Ambiguities and Values Held by Environmental Professionals

The terms used to describe and negotiate environmental quality are both ambiguous and value-laden. Stakeholders intimately and actively involved in the management of forested lands were interviewed and found to use ambiguous, tautological, and value-laden definitions of terms such as health, biodiversity, sustainability, and naturalness. This confusing language hinders public participation efforts and produces calls to regulate and remove discretion from environmental professionals. Our data come from in-depth interviews with environmental management professionals and other stakeholders heavily vested in negotiating the fate of forested lands. We contend that environmental science and management will be more effective if its practitioners embrace and make explicit these ambiguous and evaluative qualities rather than ignore and disguise them.