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[en] This project inquired into the judgments and beliefs of people living near DOE reservations and facilities at Oak Ridge, Tennessee; Hanford, Washington; and Los Alamos, Tennessee about bioremediation of subsurface contamination. The purpose of the investigation was to identify strategies based on these judgments and beliefs for enhancing public support of bioremediation. Several methods were used to collect and analyze data including content analysis of transcripts of face-to-face personal interviews, factor analysis of subjective perspectives using Q methodology, and statistical analysis of results from a large-sample randomized telephone survey. Content analysis of interview transcripts identified themes about public perceptions and constructions of contamination risk, risk management, and risk managers. This analysis revealed that those who have no employment relationship at the sites and are not engaged in technical professions are most concerned about contamination risks. We also found that most interviewees are unfamiliar with subsurface contamination risks and how they can be reduced, believe they have little control over exposure, are frustrated with the lack of progress in remediation, are concerned about a lack of commitment of DOE to full remediation, and distrust site managers to act in the public interest. Concern is also expressed over frequent site management turnover, excessive secrecy, ineffective and biased communication, perceived attempts to talk the public into accepting risk, and apparent lack of concern about community welfare. In the telephone survey, we asked respondents who were aware of site contamination about their perceptions of risk from exposure to subsurface contamination. Response analysis revealed that most people believe that they are at significant risk from subsurface contamination but they acknowledge that more education is needed to calibrate risk perceptions against scientific risk assessments. Most rate their personal control over exposure as low. Slightly more than half believe that risk reduction should be balanced against cost. We also found that distrust of DOE and its contractors exists, primarily due to the perception that site managers do not share public values; hence, the public is generally unwilling to defer to DOE in its decision-making. The concomitant belief of inefficacy confounds distrust by generating frustration that DOE does not care. Moreover, the public is split with respect to trust of each other, primarily because of the belief that citizens lack technical competence. With respect to bioremediation support, we found that more than 40% of the public has no opinion. However, of those who do, 3 of 4 are favorably disposed - particularly among those who believe that risk is lower and who are more trusting of site management. We presented survey respondents with four alternative participation strategies based on the results of the Q analysis and asked their judgments of each. The public prefers strategies that shifts power to them. The least empowered strategy (feedback) was supported by 46%; support grew as public power increased, reaching 66% support for independently facilitated deliberation. More DOE distrust generates more support for high power strategies. We offer the following recommendations to enhance public acceptance. First, and perhaps most importantly, site managers should pursue robust trust-building efforts to gain public confidence in DOE risk management that meets public expectations. Public trust decreases risk perception, which increases public willingness to defer to site managers discretion in decision-making, which in turn increases public acceptance of the decisions that result. Second, site managers should address public concerns about bioremediation such as its effectiveness in reducing risk, performance compared to other remediation alternatives, costs compared against benefits, time required to start and complete remediation, level of risk that is currently posed by contamination, and scope of application. Third, more should be done to involve the public in bioremediation decision-making. We recommend a two-stage process: independent facilitated deliberation to build trust and address concerns about the motives and competence of site managers, followed by consultation to maintain that trust. Both stages should be inclusive, transparent, and respectful. Participation objectives and roles of participants should be well specified by the participants. A record of discussion should be published that codifies the concerns raised and how they were addressed, which will facilitate progress by averting the need to reconsider the same issues repeatedly. It is most important that the processes convince the public that its participation influences decision outcomes and that participants genuinely (informed and voluntarily) consent to risk exposure.
[en] Microorganisms are ubiquitous in subsurface environments although their populations sizes and metabolic activities can vary considerably depending on energy and nutrient inputs. As a result of their metabolic activities and the chemical properties of their cell surfaces and the exopolymers they produce, microorganisms can directly or indirectly facilitate the biotransformation of radionuclides, thus altering their solubility and overall fate and transport in the environment. Although biosorption to cell surfaces and exopolymers can be an important factor modifying the solubility of some radionuclides under specific conditions, oxidation state is often considered the single most important factor controlling their speciation and, therefore, environmental behavior.
[en] Highlights: • β-HCH was more abundant than other HCH isomers in farmland topsoils across China. • Preferential degradation of (−)-α-HCH was universal but uncorrelated with linA1. • Sphingomonas was a promising biomarker indicating total-HCH, β-HCH, and α-HCH EF. • HCH-degrading microbe and relevant function were greatly influenced by soil moisture. The wide usage of hexachlorocyclohexanes (HCHs) as pesticides has caused soil pollution and adverse health effects through direct contact or bioaccumulation in the food chain. This study quantified major HCH isomers in farmland topsoils across China, and evaluated their correlations with microbial community structure, function, and abiotic variables (e.g., moisture, pH, and temperature). Recalcitrant β-HCH was more abundant than α-, γ-, and δ-HCHs, and α-HCH enantiomeric fractions (EF) were larger than 0.5, indicating preferential degradation of (−)-α-HCH. Sphingomonas was not only a predominant population (especially in samples collected in the south), but also a promising biomarker indicating total- and β-HCH residuals, and EF values of α-HCH. Soil moisture and temperature were among the most influential factors that structured the diversity and function of soil microbial communities. The results suggested that increasing soil moisture (in the range of 5–45%) would benefit the growth of HCH-degrading populations and the enrichment of HCH-degradation related pathways. Revealing the site-specific relationships between topsoil physical, chemical, and microbial properties will benefit the in situ bioremediation of farmlands with relatively low HCH residuals across the world.
[en] The projects application goals are to: (1) To understand bacterial stress-response to the unique stressors in metal/radionuclide contamination sites; (2) To turn this understanding into a quantitative, data-driven model for exploring policies for natural and biostimulatory bioremediation; (3) To implement proposed policies in the field and compare results to model predictions; and (4) Close the experimental/computation cycle by using discrepancies between models and predictions to drive new measurements and construction of new models. The projects science goals are to: (1) Compare physiological and molecular response of three target microorganisms to environmental perturbation; (2) Deduce the underlying regulatory pathways that control these responses through analysis of phenotype, functional genomic, and molecular interaction data; (3) Use differences in the cellular responses among the target organisms to understand niche specific adaptations of the stress and metal reduction pathways; (4) From this analysis derive an understanding of the mechanisms of pathway evolution in the environment; and (5) Ultimately, derive dynamical models for the control of these pathways to predict how natural stimulation can optimize growth and metal reduction efficiency at field sites
[en] Enhanced In-Situ Bioremediation (ISB) provides increased degradation of contaminants in the subsurface by indigenous microorganisms present in the soil by manipulating this natural process. In addition, there is reduced worker risk, and decreased waste management costs associated with traditional pump and treat technology
[en] An increasing number of pesticides have been used in agriculture for protecting the crops from pests, weeds, and diseases but as much as 80 to 90% of applied pesticides hit non-target vegetation and stay as pesticide residue in the environment which is potentially a grave risk to the agricultural ecosystem. This review gives an overview of the pollution in agricultural soils by pesticides, and the remediation techniques for pesticide-contaminated soils. Currently, the remediation techniques involve physical, chemical, and biological remediation as well as combined ways for the removal of contaminants. The microbial functions in rhizosphere including gene analysis tools are fields in remediation of pesticide-contaminated soil which has generated a lot of interest lately. However, most of those studies were done in greenhouses; more research work should be done in the field conditions for proper evaluation of the efficiency of the proposed techniques. Long-term monitoring and evaluation of in situ remediation techniques should also be done in order to assess their long-term sustainability and practical applications in the field.
[en] Full text: Introduction - CRC CARE is developing a National Remediation Framework (NRF) for the remediation of contaminated sites in Australia. The NRF will comprise a series of documents to provide guidance on the practicalities and options for cleaning up contaminated sites. This paper provides an introduction to work that has been carried out for the NRF program relating to the identification of remediation options, and the assessment of particular remediation technologies. This guidance has been published in draft, and comments are being received and will allow its finalisation in the near future. Scope of guidance - The work has involved the preparation of: Guidance on the Identification of Remediation Options – this guidance paper outlines how to carry out a preliminary remediation options appraisal to determine technologies that may be feasible to remediate contaminated sites. The preliminary remediation options appraisal forms the first stage of a remediation action plan (RAP). Application Guides for various technologies – these provide guidance on the practical application of particular technologies for the treatment of contaminated soil and groundwater. Information is included on the important factors that need to be considered when planning and preparing a Remediation Action Plan, and whether treatability trials will need to be carried out. The Application Guides provide guidance on the following: Soil; Containment; Chemical immobilisation and solidification; Bioremediation; Soil washing; Thermal desorption; Excavation (and disposal). Groundwater: In Situ Air Sparging; In Situ Chemical Oxidation (and surfactant enhanced in situ chemical oxidation); Skimming systems; Monitored natural attenuation; Barrier systems (permeable reactive barriers and cut off walls); Pump and treat; Vapour: Soil vapour extraction. The presentation will provide a brief summary of the information provided, and key issues that need to be considered for each particular technology. (author)