SITE Demonstration of Slurry-Phase Biodegradation of PAH Contaminated Soil

This paper summarizes a joint Superfund Innovative Technology Evaluation (SITE) project on slurry-phase biodegradation and a project to collect information for the data base on Best Demonstrated Available Technologies (BOAT). In this 12-week study, a creosote contaminated soil from the Burlington Northern Superfund site in Brainerd, Minnesota was used to evaluate the effectiveness of the bioslurry reactors. During the demonstration, five 64-liter stainless steel bioreactors, equipped with agitation, aeration and temperature controls were used. The pilot scale study employed a 30 percent slurry, an inoculum of indigenous polynuclear aromatic hydrocarbon (PAH) degraders, and inorganic nutrients.

Total PAH degradation averaged 93.4 ± 3.2 percent over all five operating reactors in the 12 weeks with 97.4 percent degradation of the 2- and 3-ring PAHs and 90 percent degradation of the 4- to 6-ring PAHs. A study of the air emissions, both semivolatile compounds such as naphthalene, anthracene, and phenanthrene and volatile compounds such as toluene, xylene, and benzene, from the units showed that the greatest amount of emissions occurred during the loading of the reactors and during the first few days of operation. Therefore, it may not be cost-effective to require elaborate emissions controls unless there are significant quantities of volatile compounds present in the soil or water to be treated in a bioslurry reactor system.     

Comparison of gamma-ray dosimeters in a field study in the Chernobyl exclusion zone

ABSTRACT

Five different models of dosimeters were compared in the Chernobyl Inner Exclusion Zone by measuring gamma radiation in 12 locations. We used an instrument made by Mirion Technologies, Inc., as the reference, since that instrument had an NIST-traceable calibration. Two models of dosimeters gave radiation values similar to the Mirion at all levels of radiation encountered. Two other models gave similar values to the Mirion instrument at low radiation levels but not at higher radiation levels encountered. These results offer a caution regarding the accuracy of inexpensive commercially available radiation instruments.

Implications: Comparison of gamma ray dosimeters in the Chernobyl Exclusion Zone showed varying agreement with an NIST-calibrated instrument, as well as varying linearity of response to ambient radiation. These results suggest caution regarding accuracy of inexpensive dosimeters. However, dosimeters used that were manufactured in Ukraine exhibited good agreement with the reference instrument.     

Living with nuclear power: Sense of place,proximity, and risk perceptions in local host communities

Previous research notes that sense of place may intensify, and that levels of public risk perception may decrease with proximity to an established hazardous or stigmatised site. In addition, the literature suggests that sense of place may act either to mediate or moderate community perceptions of risk in such localities. This study comprised a major household survey (n = 1326) and an interview study (n = 39) and was conducted close to the nuclear power stations at Oldbury and Hinkley Point, both in the UK. It investigated the roles of perceptions of place and hazard proximity in considering (a) perceptions of risk and (b) public attitudes towards the building of a new nuclear power station in the nearby area. In addition, a novel scale was developed to measure the perceived contribution of the nearby nuclear power station to sense of place. The results suggest first, that sense of place mediates (but does not moderate) perceptions of risk in very proximate communities, and second, that public attitudes to new build in communities situated very close to established nuclear sites may be largely dependent on the extent to which the existing facility is perceived to contribute towards sense of place. The implications of these results for existing theory are discussed.     

A Framework for Responding to Coral Disease Outbreaks that Facilitates Adaptive Management

Predicted increases in coral disease outbreaks associated with climate change have implications for coral reef ecosystems and the people and industries that depend on them. It is critical that coral reef managers understand these implications and have the ability to assess and reduce risk, detect and contain outbreaks, and monitor and minimise impacts. Here, we present a coral disease response framework that has four core components: (1) an early warning system, (2) a tiered impact assessment program, (3) scaled management actions and (4) a communication plan. The early warning system combines predictive tools that monitor the risk of outbreaks of temperature-dependent coral diseases with in situ observations provided by a network of observers who regularly report on coral health and reef state. Verified reports of an increase in disease prevalence trigger a tiered response of more detailed impact assessment, targeted research and/or management actions. The response is scaled to the risk posed by the outbreak, which is a function of the severity and spatial extent of the impacts. We review potential management actions to mitigate coral disease impacts and facilitate recovery, considering emerging strategies unique to coral disease and more established strategies to support reef resilience. We also describe approaches to communicating about coral disease outbreaks that will address common misperceptions and raise awareness of the coral disease threat. By adopting this framework, managers and researchers can establish a community of practice and can develop response plans for the management of coral disease outbreaks based on local needs. The collaborations between managers and researchers we suggest will enable adaptive management of disease impacts following evaluating the cost-effectiveness of emerging response actions and incrementally improving our understanding of outbreak causation.     

Emerging technologies for removing nonpoint phosphorus from surface water and groundwater: introduction

Coastal and freshwater eutrophication continues to accelerate at sites around the world despite intense efforts to control agricultural P loss using traditional conservation and nutrient management strategies. To achieve required reductions in nonpoint P over the next decade, new tools will be needed to address P transfers from soils and applied P sources. Innovative remediation practices are being developed to remove nonpoint P sources from surface water and groundwater using P sorbing materials (PSMs) derived from natural, synthetic, and industrial sources. A wide array of technologies has been conceived, ranging from amendments that immobilize P in soils and manures to filters that remove P from agricultural drainage waters. This collection of papers summarizes theoretical modeling, laboratory, field, and economic assessments of P removal technologies. Modeling and laboratory studies demonstrate the importance of evaluating P removal technologies under controlled conditions before field deployment, and field studies highlight several challenges to P removal that may be unanticipated in the laboratory, including limited P retention by filters during storms, as well as clogging of filters due to sedimentation. Despite the potential of P removal technologies to improve water quality, gaps in our knowledge remain, and additional studies are needed to characterize the long-term performance of these technologies, as well as to more fully understand their costs and benefits in the context of whole-farm- and watershed-scale P management.     

Long-term field-scale experiment on using lime filters in an agricultural catchment

The River Yl?neenjoki catchment in southwest Finland is an area with a high agricultural nutrient load. We report here on the nutrient removal performance of three on-site lime-sand filters (F1, F2, and F3), established within or on the edge of the buffer zones. The filters contain burnt lime (CaO) or spent lime [CaO, Ca(OH), and CaCO]. Easily soluble lime results in a high pH level (>11) and leads to an efficient precipitation of soluble phosphorus (P) from the runoff. Water samples were taken from the inflow and outflow of each site in different hydrological situations. The length of the monitoring period was 4 yr for F1, 6 yr for F2, and 1.5 yr for F3. F1 and F2 significantly reduced the suspended solids (SS), total P (PTOT), and dissolved reactive P (DRP) in the treated water. The proportional reduction (%) varied but was usually clearly positive. Filter F3 was divided into two equal parts, one containing burnt lime and the other spent lime. Both filter parts removed PTOT and SS efficiently from the water; the burnt-lime part also removed DRP. The mixed-lime part removed DRP for a year, but then the efficiency decreased. The effect of filters on nitrogen compounds varied. We conclude that sand filters incorporating lime can be used together with buffer zones to reduce both P and SS load to watercourses.     

Comparison of Stream Invertebrate Response Models for Bioassessment Metrics1

Waite, Ian R., Jonathan G. Kennen, Jason T. May, Larry R. Brown, Thomas F. Cuffney, Kimberly A. Jones, and James L. Orlando, 2012. Comparison of Stream Invertebrate Response Models for Bioassessment Metrics. Journal of the American Water Resources Association (JAWRA) 48(3): 570-583. DOI: 10.1111/j.1752-1688.2011.00632.x Abstract: We aggregated invertebrate data from various sources to assemble data for modeling in two ecoregions in Oregon and one in California. Our goal was to compare the performance of models developed using multiple linear regression (MLR) techniques with models developed using three relatively new techniques: classification and regression trees (CART), random forest (RF), and boosted regression trees (BRT). We used tolerance of taxa based on richness (RICHTOL) and ratio of observed to expected taxa (O/E) as response variables and land use/land cover as explanatory variables. Responses were generally linear; therefore, there was little improvement to the MLR models when compared to models using CART and RF. In general, the four modeling techniques (MLR, CART, RF, and BRT) consistently selected the same primary explanatory variables for each region. However, results from the BRT models showed significant improvement over the MLR models for each region; increases in R² from 0.09 to 0.20. The O/E metric that was derived from models specifically calibrated for Oregon consistently had lower R² values than RICHTOL for the two regions tested. Modeled O/E R² values were between 0.06 and 0.10 lower for each of the four modeling methods applied in the Willamette Valley and were between 0.19 and 0.36 points lower for the Blue Mountains. As a result, BRT models may indeed represent a good alternative to MLR for modeling species distribution relative to environmental variables.     

Is Urban Stream Restoration Worth It?1

Kenney, Melissa A., Peter R. Wilcock, Benjamin F. Hobbs, Nicholas E. Flores, and Daniela C. Martínez, 2012. Is Urban Stream Restoration Worth It? Journal of the American Water Resources Association (JAWRA) 48(3): 603-615. DOI: 10.1111/j.1752-1688.2011.00635.x Abstract: Public investment in urban stream restoration is growing, yet little has been done to quantify whether its benefits outweigh its cost. The most common drivers of urban stream projects are water quality improvement and infrastructure protection, although recreational and aesthetic benefits are often important community goals. We use standard economic methods to show that these contributions of restoration can be quantified and compared to costs. The approach is demonstrated with a case study in Baltimore, Maryland, a city with a legal mandate to reduce its pollutant load. Typical urban stream restoration costs of US$500-1,200 per foot are larger than the cost of the least expensive alternatives for management of nitrogen loads from stormwater (here, detention ponds, equivalent to $30-120 per foot of restored stream) and for protecting infrastructure (rip-rap armoring of streambanks, at $0-120 per foot). However, the higher costs of stream restoration can in some cases be justified by its aesthetic and recreational benefits, valued using a contingent valuation survey at $560-1,100 per foot. We do not intend to provide a definitive answer regarding the worth of stream restoration, but demonstrate that questions of worth can be asked and answered. Broader application of economic analysis would provide a defensible basis for understanding restoration benefits and for making restoration decisions.     

The Effects of Hypoxia on Sediment Nitrogen Cycling in the Baltic Sea

Primary production in the eutrophic Baltic Sea is limited by nitrogen availability; hence denitrification (natural transformation of nitrate to gaseous N₂) in the sediments is crucial in mitigating the effects of eutrophication. This study shows that dissimilatory nitrate reduction to ammonium (DNRA) process, where nitrogen is not removed but instead recycled in the system, dominates nitrate reduction in low oxygen conditions (O₂ <110 μM), which have been persistent in the central Gulf of Finland during the past decade. The nitrogen removal rates measured in this study show that nitrogen removal has decreased in the Gulf of Finland compared to rates measured in mid-1990s and the decrease is most likely caused by the increased bottom water hypoxia.