Sustainable soil remediation by refrigerated condensation at sites with “high‐concentration” recalcitrant compounds and NAPL: Two case studies

Remediation of recalcitrant compounds at sites with high concentrations of volatile organic compounds (VOCs) or nonaqueous‐phase liquids (NAPLs) can present significant technical and financial (long‐term) risk for stakeholders. Until recently, however, sustainability has not been included as a significant factor to be considered in the feasibility and risk evaluation for remediation technologies. The authors present a framework for which sustainability can be incorporated into the remediation selection criteria focusing specifically on off‐gas treatment selection for soil vapor extraction (SVE) remediation technology. SVE is generally considered an old and standard approach to in situ remediation of soils at a contaminated site. The focus on off‐gas treatment technology selection in this article allows for more in‐depth analysis of the feasibility evaluation process and how sustainable practices might influence the process. SVE is more commonly employed for recovery of VOCs from soils than other technologies and generally employs granular activated carbon (GAC), catalytic, or thermal oxidation, or an emerging alternative technology known as cryogenic‐compression and condensation combined with regenerative adsorption (C3–Technology). Of particular challenge to the off‐gas treatment selection process is the potential variety of chemical constituents and concentrations changing over time. Guidance is available regarding selection of off‐gas treatment technology (Air Force Center for Environmental Excellence, 1996; U.S. Environmental Protection Agency, 2006). However, there are common shortcomings of off‐gas treatment technology guidance and applications; practitioners have rarely considered sustainability and environmental impact of off‐gas treatment technology selection. This evaluation includes consideration of environmental sustainability in the selection of off‐gas treatment technologies and a region‐specific (Los Angeles, California) cost per pound and time of remediation comparisons between GAC, thermal oxidation, and C3–Technology. © 2008 Wiley Periodicals, Inc.     

Improved soil carbonate determination by FT-IR and X-ray analysis

In forest soils on calcareous parent material, carbonate is a key component that influences both chemical and physical soil properties and thus fertility and productivity. At low organic carbon contents, it is difficult to distinguish between organic and inorganic carbon, e.g. carbonates, in soils. The common gas-volumetric method to determine carbonate has a number of disadvantages. We hypothesize that a combination of two spectroscopic methods, which account for different forms of carbonate, can be used to model soil carbonate in our region. Fourier transform mid-infrared spectroscopy was combined with X-ray diffraction to develop a model based on partial least squares regression. Results of the gas-volumetric Scheibler method were corrected for the calcite/dolomite ratio. The best model performance was achieved when we combined the two analytical methods using four principal components. The root mean squared error of prediction decreased from 13.07 to 11.57, while full cross-validation explained 94.5 % of the variance of the carbonate content. This is the first time that a combination of the proposed methods has been used to predict carbonate in forest soils, offering a simple method to precisely estimate soil carbonate contents while increasing accuracy in comparison with spectroscopic approaches proposed earlier. This approach has the potential to complement or substitute gas-volumetric methods, specifically in study areas with low soil heterogeneity and similar parent material or in long-term monitoring by consecutive sampling.     

Introduction to Therm Net Technology

The Introduction to Therm Net technology is an overview of how radio frequency (RF) beating can be implemented to enhance conventional remediation technologies. Included in the article is a case study of a project conducted in March 1996 at a gasoline release site. The project consisted of a “hot spot” application to reduce BETX concentrations to achieve site closure. The application consisted of RF heating, soil vapor extraction, and groundwater ventilation. A bench scale study was also conducted to measure the effects that RF heating and vapor extraction had on the removal of PAH constitutents from a coal tar sludge. Up to 100 percent reductions were observed for some of the constituents in the study. Also included is a graphical representation of temperature versus vapor pressure for contaminants typically encountered at remediation sites, illustrating that as temperature increases, the removal rate increases.     

Crop Biotechnology for the Environment?

In public debates, agricultural biotechnology is almost invariably discussed as a potential threat to the environment and to human health. Without downplaying the risks associated with this technology we emphasize that if properly regulated, it can be a forceful tool to solve environmental problems and promote human health. Agricultural biotechnology can reduce environmental problems in at least three ways: it can diminish the need for environmentally damaging agricultural practices such as pesticides, fertilizers, tillage, and irrigation. It can reduce the land area needed for agriculture, thus reducing the CO₂ effect of agriculture and improving biodiversity. It can produce energy in a CO₂-neutral way (especially if new technologies involving the cultivation of microalgae become successful). Furthermore, agricultural biotechnology can have positive effects on human health by decreasing occupational and dietary exposure to pesticides, improving the nutritional value of food, and producing pharmaceuticals more efficiently. We argue that those who wish to give high priority to environmental goals cannot afford any longer to be mere onlookers while others decide the future directions of agricultural biotechnology.     

Risk and vulnerability analysis: A feasible process for local climate adaptation in Sweden?

Climate change is an important new challenge for local authorities. This study analyses the potential for using the Swedish mandatory process for risk and vulnerability analysis (RVA) as a vehicle to improve local climate adaptation work. An advantage with RVA is its comprehensive approach in dealing with all relevant threats and all vital functions of society. In order to test the applicability of incorporating climate adaptation into RVA, we studied practical experiences from three Swedish municipalities. In all municipalities, a pre-study to identify relevant climate-induced events was performed. In one municipality, this was followed by a more detailed analysis of the potential impacts of these events on the functions of the various administrations and companies within the local authority. Problems identified in successful integration of climate change into the municipal RVA process were lack of sufficient knowledge to identify the impacts of climate change on the level of the respective specialist or district administration and lack of resources to perform the analysis. There were also some difficulties in including a long-term perspective relevant for climate adaptation into RVA, which usually focuses on current threats. A positive outcome was that work on extreme climate events in RVA provided a traceable method to identify events with a potentially great impact on the function of local society and results that could be fed into other ongoing processes, such as spatial planning and housing plans.     

Water quality dynamics and hydrology in nitrate loaded riparian zones in the Netherlands

Riparian zones are known to function as buffers, reducing non-point source pollution from agricultural land to streams. In the Netherlands, riparian zones are subject to high nitrogen inputs. We combined hydrological, chemical and soil profile data with groundwater modelling to evaluate whether chronically N loaded riparian zones were still mitigating diffuse nitrate fluxes. Hydraulic parameters and water quality were monitored over 2 years in 50 piezometres in a forested and grassland riparian zone. Average nitrate loadings were high in the forested zone with 87 g NO(3)(-)-N m(-2) y(-1) and significantly lower in the grassland zone with 15 g NO(3)(-)-N m(-2) y(-1). Groundwater from a second aquifer diluted the nitrate loaded agricultural runoff. Biological N removal however occurred in both riparian zones, the grassland zone removed about 63% of the incoming nitrate load, whereas in the forested zone clear symptoms of saturation were visible and only 38% of the nitrate load was removed.     

Off‐gas treatment carbon footprint calculator: Form and function

The quantification of greenhouse gas (GHG) emissions can be a powerful sustainability measurement indicator for assessing environmental impacts of various operations, which can include remediation of chemically impacted media or construction projects. A carbon footprint calculator was developed and is presented in this article as one tool for applying sustainable practices to environmental remediation—specifically to assess the GHG footprint for remediation projects. The calculator is constructed from a compilation of published metrics and “standards.” © 2008 Wiley Periodicals, Inc.     

Gender impact on first trimester markers in Down syndrome screening

The influence of fetal gender on the level in the first trimester of the serological markers alpha-fetoprotein (AFP), pregnancy-associated plasma protein-A (PAPP-A) and free beta human chorionic gonadotropin (βhCG) and on nuchal translucency is described for 2637 singleton pregnancies with normal outcome. Mean log MoM values for pregnancies with female and male fetuses were calculated using regression of log marker values on gestational age expressed as crown rump length and on maternal weight. A pronounced gender impact was found for free βhCG, being 16% higher for female than for male fetuses. Copyright © 2002 John Wiley & Sons, Ltd.