Magnus Sparrevik

Nutrient-limited biodegradation of PAH in various soil strata at a creosote contaminated site

The effects of nutrient addition on the in situ biodegradation of polycyclic aromatic hydrocarbons in creosote contaminated soil were studied in soil columns taken from various soil strata at a wood preserving plant in Norway. Three samples were used: one from the topsoil (0–0.5 m), one from an organic rich layer (2–2.5 m) and one from the sandy aquifer (4.5–5 m). The addition of inorganic nitrogen and phosphorous stimulated the degradation of polycyclic aromatic hydrocarbons (PAHs) in the top soil and the aquifer sand. These two soils, which differed strongly in contamination levels, responded similarly to nutrient addition with the corresponding degradation of 4-ring PAHs. The ratio between available nitrogen (N) and phosphorous (P) might explain the degree of degradation observed for the 4-ring PAHs. However, the degree of degradation of 3-ring PAHs did not significantly increase after nutrient addition. An increase in the respiration rate, after nutrient addition, could only be observed in the topsoil. In the aquifer sand, 4-ring PAH degradation was not accompanied by an increase in the respiration rate or the number of heterotrophic micro-organisms. PAH degradation in the organic layer did not respond to nutrient addition. This was probably due to the low availability of the contaminants for micro-organisms, as a result of sorption to the soil organic matter. Our data illustrate the need for a better understanding of the role of nutrients in the degradation of high molecular weight hydrocarbons for the successful application of bioremediation at PAH contaminated sites.

Persistence of the De-Icing Additive Benzotriazole at an Abandoned Airport

The environmental fate of many of the additives in the deicing agents used at airports is poorly understood. One and two years after deicing activities ceased, soil and groundwater samples were taken at an abandoned airport. Benzotriazole (BT), a corrosion and flame inhibitor, was found in low concentrations in soils along runways (mean 0.33 mg/kg), at a snow disposal site (0.66 mg/kg), as well as in sediments of a drainage ditch (13 mg/kg). Locally, high BT concentrations were found in the groundwater below the deicing pad, the regeneration plant and the snow disposal site (1.2 to 1100 μg/l). Methyl substituted triazoles or tolytriazoles (MeBT) were found in concentrations less than 10% of the BT concentration. Propylene glycol was not detected in soil samples and in only one of the groundwater samples. Microtox tests of the water samples revealed no acute toxic response, however a reduction in nitrification rate was observed (14–43%). The nitrification response could not be related directly to the BT concentration in the samples, although samples with a high BT concentration showed the largest reduction in nitrification rate. BT showed very little sorption in various soil matrices, only peat and compost with a high organic carbon content showed significant sorption. Sorption could be best described using a Freundlich isotherm. These results indicate a high mobility and possibly long persistence of BT in soil and groundwater, which may be attributed to the absence of microbial degradation of BT.

Use of Life Cycle Assessments To Evaluate the Environmental Footprint of Contaminated Sediment Remediation

Ecological and human risks often drive the selection of remedial alternatives for contaminated sediments. Traditional human and ecological risk assessment (HERA) includes assessing risk for benthic organisms and aquatic fauna associated with exposure to contaminated sediments before and after remediation as well as risk for human exposure but does not consider the environmental footprint associated with implementing remedial alternatives. Assessment of environmental effects over the whole life cycle (i.e., Life Cycle Assessment, LCA) could complement HERA and help in selecting the most appropriate sediment management alternative. Even though LCA has been developed and applied in multiple environmental management cases, applications to contaminated sediments and marine ecosystems are in general less frequent. This paper implements LCA methodology for the case of the polychlorinated dibenzo-p-dioxins and -furans (PCDD/F)-contaminated Grenland fjord in Norway. LCA was applied to investigate the environmental footprint of different active and passive thin-layer capping alternatives as compared to natural recovery. The results showed that capping was preferable to natural recovery when analysis is limited to effects related to the site contamination. Incorporation of impacts related to the use of resources and energy during the implementation of a thin layer cap increase the environmental footprint by over 1 order of magnitude, making capping inferior to the natural recovery alternative. Use of biomass-derived activated carbon, where carbon dioxide is sequestered during the production process, reduces the overall environmental impact to that of natural recovery. The results from this study show that LCA may be a valuable tool for assessing the environmental footprint of sediment remediation projects and for sustainable sediment management.

Life cycle assessment to evaluate the environmental impact of biochar implementation in conservation agriculture in Zambia.

Biochar amendment to soil is a potential technology for carbon storage and climate change mitigation. It may, in addition, be a valuable soil fertility enhancer for agricultural purposes in sandy and/or weathered soils. A life cycle assessment including ecological, health and resource impacts has been conducted for field sites in Zambia to evaluate the overall impacts of biochar for agricultural use. The life cycle impacts from conservation farming using cultivation growth basins and precision fertilization with and without biochar addition were in the present study compared to conventional agricultural methods. Three different biochar production methods were evaluated: traditional earth-mound kilns, improved retort kilns, and micro top-lit updraft (TLUD) gasifier stoves. The results confirm that the use of biochar in conservation farming is beneficial for climate change mitigation purposes. However, when including health impacts from particle emissions originating from biochar production, conservation farming plus biochar from earth-mound kilns generally results in a larger negative effect over the whole life cycle than conservation farming without biochar addition. The use of cleaner technologies such as retort kilns or TLUDs can overcome this problem, mainly because fewer particles and less volatile organic compounds, methane and carbon monoxide are emitted. These results emphasize the need for a holistic view on biochar use in agricultural systems. Of special importance is the biochar production technique which has to be evaluated from both environmental/climate, health and social perspectives.

Use of Stochastic Multi-Criteria Decision Analysis to Support Sustainable Management of Contaminated Sediments

Sustainable management of contaminated sediments requires careful prioritization of available resources and focuses on efforts to optimize decisions that consider environmental, economic, and societal aspects simultaneously. This may be achieved by combining different analytical approaches such as risk analysis (RA), life cycle analysis (LCA), multicriteria decision analysis (MCDA), and economic valuation methods. We propose the use of stochastic MCDA based on outranking algorithms to implement integrative sustainability strategies for sediment management. In this paper we use the method to select the best sediment management alternatives for the dibenzo-p-dioxin and -furan (PCDD/F) contaminated Grenland fjord in Norway. In the analysis, the benefits of health risk reductions and socio-economic benefits from removing seafood health advisories are evaluated against the detriments of remedial costs and life cycle environmental impacts. A value-plural based weighing of criteria is compared to criteria weights mimicking traditional cost-effectiveness (CEA) and cost-benefit (CBA) analyses. Capping highly contaminated areas in the inner or outer fjord is identified as the most preferable remediation alternative under all criteria schemes and the results are confirmed by a probabilistic sensitivity analysis. The proposed methodology can serve as a flexible framework for future decision support and can be a step toward more sustainable decision making for contaminated sediment management. It may be applicable to the broader field of ecosystem restoration for trade-off analysis between ecosystem services and restoration costs.

Use of multicriteria involvement processes to enhance transparency and stakeholder participation at Bergen Harbor, Norway

Use of participatory stakeholder engagement processes could be important to reduce the risk of potential conflicts in managing contaminated sites. Most stakeholder engagement techniques are qualitative in nature and require experienced facilitators. This study proposes a multicriteria involvement process to enhance transparency and stakeholder participation and applies it to a contaminated sediment management case study for Bergen Harbor, Norway. The suggested multicriteria involvement process builds on the quantitative principles of multicriteria decision analysis and also incorporates group interaction and learning through qualitative participatory methods. Three different advisory groups consisting of local residents, local stakeholders, and nonresident sediment experts were invited to participate in a stakeholder engagement process to provide consensual comparative advice on sediment remediation alternatives. In order for stakeholders or residents to be able to embrace a complex decision such as selection of remediation alternatives, the involvement process with lateral learning, combined with multicriteria decision analysis providing structure, robustness and transparent documentation was preferable. In addition, a multicriteria involvement process resulted in consistent ranking of remediation alternatives across residents, stakeholder, and experts, relative to individual intuitive ranking without the multicriteria involvement process.

Environmental and Socioeconomic Impacts of Utilizing Waste for Biochar in Rural Areas in Indonesia−A Systems Perspective

Biochar is the product of incomplete combustion (pyrolysis) of organic material. In rural areas, it can be used as a soil amendment to increase soil fertility. Fuel-constrained villagers may however prefer to use biochar briquettes as a higher-value fuel for cooking over applying it to soils. A systems-oriented analysis using life cycle assessment (LCA) and cost benefit analysis (CBA) was conducted to analyze these two alternative uses of biochar, applying the study to a rural village system in Indonesia. The results showed soil amendment for enhanced agricultural production to be the preferential choice with a positive benefit to the baseline scenario of -26 ecopoints (LCA) and -173 USD (CBA) annually pr. household. In this case, the positive effects of carbon sequestration to the soil and the economic value of the increased agricultural production outweighed the negative environmental impacts from biochar production and the related production costs. Use of biochar in briquettes for cooking fuel yielded negative net effects in both the LCA and CBA (85 ecopoints and 176 USD), even when positive health effects from reduced indoor air pollution were included. The main reasons for this are that emissions during biochar production are not compensated by carbon sequestration and that briquette making is labor-intensive. The results emphasize the importance of investigating and documenting the carbon storage effect and the agricultural benefit in biochar production-utilization systems for a sustainable use. Further research focus on efficient production is necessary due to the large environmental impact of biochar production. In addition, biochar should continue to be used in those soils where the agricultural effect is most beneficial.

The importance of sulphide binding for leaching of heavy metals from contaminated Norwegian marine sediments treated by stabilization/solidification.

Over time, Norwegian fjords and harbour areas have received contaminants from industrial activities and urban run‐off, and measures to remediate contaminated marine sediments are therefore needed. Stabilization/solidification (S/S) technology, in which the contaminated marine sediments are mixed with cement and other binding agents, has been shown to be a promising remediation technology. This paper summarizes a study of the environmental effect of stabilization, highlighting the importance of sulphide binding governing the leaching of heavy metals from the S/S of contaminated marine sediments. The study is a part of a research project focusing on developing effective methods for S/S of contaminated seabed sediments for use in new construction areas. Four cementitious binders were tested on sediments from six different locations: Bergen, Gilhus, Grenland, Hammerfest, Sandvika and Trondheim. The sediments differed with respect to properties such as concentration of contaminants, water content, organic content and grain size distribution. Portland cement, Portland cement with fly ash, industry cement, and sulphate resistant cement, were tested as binders. The leaching from the S/S sediments after 28 days of curing was measured by using a standard leaching batch test (EN 12457‐2: 2003), with seawater as leaching agent. The eluate was analysed for pH and redox, as well as content of heavy metals and organic contaminants. Available volatile sulphide (AVS) and simultaneously extractable metals (SEM) were also measured in the sediments. This paper focuses on the leaching of lead (Pb) and copper (Cu). A reduced leaching of Pb after stabilization was observed for the mixtures, whereas the leaching of Cu from Hammerfest sediments increased substantially after stabilization for all cementitious additions. Experiments show that Hammerfest samples had lower values of AVS than the other sediments. This was confirmed by the SEM/AVS analysis, highlighting the importance of sulphide binding for mobility of heavy metals in stabilized marine sediments. For practical application of S/S technology to contaminated sediments, it is important to assess the leachability of the stabilized material taking sediment conditions such as AVS content into account. It is however important to be aware that the mobility of contaminants from a S/S sediment is dependent on a combination of contaminant concentrations and hydraulic conductivity (permeability). When devising S/S procedures for environmental projects, in addition to physical strength, the binder should be optimized in relation to leaching and permeability in order to achieve the lowest transport of contaminants through the material.

From ecological risk assessments to risk governance: Evaluation of the Norwegian management system for contaminated sediments

Managing of contaminated sediments is a complex process that will naturally have to balance scientific, political, and economic interests. This study evaluates the Norwegian system for managing contaminated sediments toward a generic system for risk governance encompassing both knowledge, legally prescribed procedures, and social values. The review has been performed examining the management plans for 17 prioritized contaminated fjord systems in Norway. The results indicate a strong focus in the Norwegian management system on ecological risk assessment. This facilitates selection of local sustainable remediation measures, but may also complicate the balance toward other relevant interests in a decision-making process. The Norwegian system lacks management tools to identify and handle ambiguity through concern assessments and stakeholder involvement, and the decision-making process seems to a large extent based on ad hoc decisions, making it difficult to incorporate and document multicriteria evaluations into the management process. To develop a sustainable management system, encompassing environmental, economical, and social interests, a stronger focus on concern assessment and multicriteria evaluations is required.

Risk Management Practices

The inevitable public unease in the wake of large infrastructure failure prompts questions regarding how to properly define and manage the risks of various engineered activities to socially acceptable levels. A changing climate may add additional vulnerability to infrastructure and thus should be considered in risk management strategies. Current implementations of risk management processes differ across public agencies, but often rely on a concept of Tolerable Risk. Tolerable Risk is a numerical value for the boundary—in a continuum of management alternatives—below which risk is tolerated to secure societal benefits, though engineering interventions may be still be necessary and proper to achieve higher degrees of protection. This chapter gives an overview of risk management and introduces the Tolerable Risk framework, reviews and summarizes risk management frameworks for several federal and foreign agencies, and recommends key features and necessary steps for a Tolerable Risk framework implementation. The ideas in this chapter draw extensively from a March 2008 interagency workshop on Tolerable Risk sponsored by the U.S. Army Corps of Engineers, the U.S. Bureau of Reclamation, and the Federal Energy Regulatory Commission, and attended by several additional federal and foreign agencies [33].