Global Efforts to Advance Remediation at Contaminated Sites
Overview
Valence state: The combining capacity of an atom or radical determined by the number of electrons that it will lose, add, or share when it reacts with other atoms.
Source: The American Heritage™ Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.
free product: A NAPL found in the subsurface in sufficient quantity that it can be partially recovered by pumping or gravity drain.
aerobic: Direct aerobic metabolism involves microbial reactions that require oxygen to go forward. The bacteria uses a carbon substrate as the electron donor and oxygen as the electron acceptor. Degradation of contaminants that are susceptible to aerobic degradation but not anaerobic often ceases in the vicinity of the source zone because of oxygen depletion. This can sometimes be reversed by adding oxygen in the form of air (air sparging, bioventing), ozone, or slow oxygen release compound (e.g., ORC(r)).
Aerobic dechlorination may also occur via cometabolism where the dechlorination is incidental to the metabolic activities of the organisms. In this case, contaminants are degraded by microbial enzymes that are metabolizing other organic substrates. Cometabolic dechlorination does not appear to produce energy for the organism. At pilot- or full-scale treatment, cometabolic and direct dechlorination may be indistinguishable, and both processes may contribute to contaminant removal. For aerobic cometabolism to occur there must be sufficient oxygen and a suitable substrate which allows the microbe to produce the appropriate enzyme. These conditions may be present naturally but often in the presence of a source area oxygen and a substrate such as methane or propane will need to be introduced.
Adapted from US. EPA 2006 Engineering Issue: In Situ and Ex Situ Biodegradation Technologies for Remediation of Contaminated Sites
anaerobic: Direct anaerobic metabolism involves microbial reactions occurring in the absence of oxygen and encompasses many processes, including fermentation, methanogenesis, reductive dechlorination, sulfate-reducing activities, and denitrification. Depending on the contaminant of concern, a subset of these activities may be cultivated. In anaerobic metabolism, nitrate, sulfate, carbon dioxide, oxidized metals, or organic compounds may replace oxygen as the electron acceptor.
Anaerobic dechlorination also may occur via cometabolism where the dechlorination is incidental to the metabolic activities of the organisms. In this case, contaminants are degraded by microbial enzymes that are metabolizing other organic substrates. Cometabolic dechlorination does not appear to produce energy for the organism. At pilot- or full-scale treatment, cometabolic and direct dechlorination may be indistinguishable, and both processes may contribute to contaminant removal.
Quoted from US. EPA 2006 Engineering Issue: In Situ and Ex Situ Biodegradation Technologies for Remediation of Contaminated Sites
architecture: "Architecture" refers to the physical distribution of the contaminant in the subsurface. Residuals that take the form of long thin ganglia or small dispersed globules provide a larger surface area that will dissolve much faster than if the same amount of liquid were concentrated in a competent pool.
Sources: For purposes of this discussion, a DNAPL source zone includes the zone that encompasses the entire subsurface volume in which DNAPL is present either at residual saturation or as "pools" of accumulation above confining units. In addition, the DNAPL source zone includes regions that have come into contact with DNAPL that may be storing contaminant mass as a result of diffusion of DNAPL into the soil or rock matrix.
source zone: For purposes of this discussion, a DNAPL source zone includes the zone that encompasses the entire subsurface volume in which DNAPL is present either at residual saturation or as "pools" of accumulation above confining units. In addition, the DNAPL source zone includes regions that have come into contact with DNAPL that may be storing contaminant mass as a result of diffusion of DNAPL into the soil or rock matrix.
focal ulceration: The process or fact of a localized area being eroded away.
metaplasia of the glandular stomach: A change of cells to a form that does not normally occur in the tissue in which it is found.
hyperplasia of the glandular stomach: A condition in which there is an increase in the number of normal cells in a tissue or organ.
histiocytic: Degenerative.
duodenum: First part of the small intestine.
microcytic: Any abnormally small cell.
squamous cell papillomas: A small solid benign tumor with a clear-cut border that projects above the surrounding tissue.
squamous cell carcinomas: Cancer that begins in squamous cells-thin, flat cells that look under the microscope like fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of hollow organs of the body, and the passages of the respiratory and digestive tracts. Squamous cell carcinomas may arise in any of these tissues.
jejunum: The middle portion of the small intestine, between duodenum and ileum. It represents about 2/5 of the remaining portion of the small intestine below duodenum.
ileum: The distal and narrowest portion of the small intestine.
squamous: Flat cells that look like fish scales.
metaplasia: A condition in which there is a change of one adult cell type to another similar adult cell type.
ossification: The process of creating bone, that is of transforming cartilage (or fibrous tissue) into bone.
clastogenesis: Any process resulting in the breakage of chromosomes.
neoplastic: Abnormal and uncontrolled growth of cells.
ulceration: The process or fact of being eroded away.
leucocytosis: An elevation of the total number of white cells in blood.
neutrophils: A type of white blood cell.
chromodulin: A small protein that binds four trivalent chromium ions.
biomagnification: The increased accumulation and concentration of a contaminant at higher levels of the food chain; organisms higher on the food chain will have larger amounts of contaminants than those lower on the food chain, because the contaminants are not eliminated or broken down into other chemicals within the organisms.
exencephaly: Cerebral tissue herniation through a congenital or acquired defect in the skull.
everted viscera: Rotated body organs in the chest cavity.
To Be Considered: Documents, such as federal or state guidances, that are not legally binding but may be relevant to the topic in question.
gaining: A gaining surface water body is one where groundwater flows into it.
losing: A surface water body is losing when there is a permeable sediment bed that is not in contact with the groundwater allowing the surface water to seep through it.
fluvial: Of or pertaining to flow in rivers and streams.
lacustrine: Of or pertaining to a lake as in lacustrine sediments—sediments at the bottom of a lake.
lipid: Any class of fats that are insoluble in water.
lipophilic: Able to dissolve in lipids—in this case fatty tissue.
organelles: A part of a cell such as mitochondrion, vacuole, or chloroplast that plays a specific role in how the cell functions and membranes.
RfD: The RfD is an estimate of a daily exposure of the human population (including sensitive sub-groups) to a substance that is likely to be without "the appreciable risk of deleterious effects during a lifetime." An RfD is expressed in units of mg/kg-day.
autonomic: That part of the nervous system that controls non-conscious actions such as heart rate, perspiration and digestion.
ataxia: Lack of muscle coordination.
funnel-and-gate configuration: A system where low-permeability walls (the funnel) placed in the saturated zone direct contaminated ground-water toward a permeable treatment zone (the gate)
References: ATSDR (Agency for Toxic Substances and Disease Registry). 2015. Draft Toxicological Profile for Perfluoroalkyls. 574 pp.
EFSA (European Food Safety Authority). 2008. Opinion of the scientific panel on contaminants in the food chain on perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) and their salts. EFSA Journal 653:1-131.
Hekster, F.M., R.W.P.M. Laane, and P. de Voogt. 2003. Environmental and toxicity effects of perfluoroalkylated substances. Reviews of Environmental Contamination and Toxicology 179:99-121.
Higgins, C. and R. Luthy. 2006. Sorption of perfluorinated surfactants on sediments. Environmental Science & Technology 40(23):7251-7256.
HSDB (Hazardous Substances Data Bank). 2012 Update. Perfluorooctanoic acid.
Kaiser, M.A., B.S. Larsen, C-P.C. Kao, and R.C. Buck. 2005. Vapor pressures of perfluorooctanoic, -nonanoic, -decanoic, -undecanoic, and -dodecanoic acids. Journal of Chemical and Engineering Data 50(6):1841-1843.
Kauck, E.A. and A.R. Diesslin. 1951. Some properties of perfluorocarboxylic acids. Industrial and Engineering Chemical Research 43(10):2332-2334.
Lewis, R.J., Sr., ed. 2004. Sax's Dangerous Properties of Industrial Materials. 11th ed. Wiley-Interscience, Hoboken, NJ. V3:2860.
Lide, D.R. 2007. CRC Handbook of Chemistry and Physics. 88th ed. CRC Press, Boca Raton, FL. 3-412.
SRC (Syracuse Research Corporation). 2016. PHYSPROP Database. SRC Scientific Databases,
Accessed May 2016.
UNEP (United Nations Environmental Program). 2015. Proposal to List Pentadecafluorooctanoic Acid (CAS No: 335-67-1, PFOA, Perfluorooctanoic Acid), Its Salts and PFOA-Related Compounds in Annexes A, B and/or C to the Stockholm Convention on Persistent Organic Pollutants. UNEP/POPS/POPRC.11/5.
USEPA (U.S. Environmental Protection Agency). 2016. Drinking Water Health Advisory for Perfluorooctanoic Acid (PFOA).#pdfsmall# Office of Water, EPA 822-R-16-005, 103 pp
Technology innovation efforts of the U.S. Environmental Protection Agency (USEPA) Superfund Program focus on advancing the state of the practice for remediation of contaminated sites. Advanced practices that are based on new or updated technologies, improved processes, and evolving science allow USEPA and other stakeholders to clean up contaminated sites in a more efficient and sustainable manner while achieving our core mission of protecting human health and the environment. Recent USEPA Superfund initiatives focus on accelerating site cleanups, optimizing performance of cleanup remedies, eliminating unnecessary use of resources, preserving water resources, and assuring remedy resilience to a changing climate.
In light of today's global economy and environment, USEPA and other agencies throughout the world recognize the need to continuously exchange information and leverage lessons learned by organizations and professionals in diverse situations. Sharing of the knowledge and experiences increases productivity within our global community and helps us collectively refine our site remediation practices in ways that address global issues such as climate change.
USEPA's Superfund Program, which focuses on the nation's contaminated sites of highest priority, continues to expand capabilities for exchanging information globally as well as domestically through online methods such as websites and Internet seminars and through periodic meetings and conferences.
Events: 2019-2020
April 5, 2019: Brownfield Redevelopment in the EU. Brussels, Belgium. This conference hosted by the European Committee of the Regions promotes brownfield redevelopment as a solution to limit urban sprawl, land take and soil sealing. The conference agenda includes presentations by European, regional and local stakeholders on topics such as inspiring policies and good practices and explores the potential offered by EU funds.
May 8, 2019. 5th Meeting of Soil as a Resource Working Group of the Common Forum. Lëtzebuerg, Luxembourg. Discussions focus on Land Management Assessment, Research, Knowledge Base (LANDMARK) research during 2020.
May 8-10, 2019: Common Forum Springtime Meeting 2019. Lëtzebuerg, Luxembourg. The agenda addresses:
- Background concentrations/values
- How to strengthen European soil policy
- Effectiveness in soil protection — how to measure success
May 20-24, 2019: AquaConSoil 2019. Antwerp, Belgium. This 15th International Conference on Sustainable Use and Management of Soil, Sediment and Water Resources addresses:
- Soil and water in the digital world
- Advances in assessment of risk and monitoring of soil, sediment and water quality
- Diffuse and emerging contaminants in the soil sediment water system
- Advances in remediation technologies
- Strategies and management of contaminated land including legal, social and economic aspects
- Land stewardship
- Land, soil, water and sediment in the circular economy
October 23-25, 2019: 14th Meeting of the International Committee on Contaminated Land (ICCL) 2019. Lima, Perú. Topics include:
- Mercury contaminated sites management and the application of Minamata convention
- Main aspects of/ How to make the risk assessment and conceptual model on contaminated sites
- Stockholm Convention and managing POP contamination
- Remediation of contaminated sites by heavy metals
- Economic aspects of the management of contaminated sites: management tools, cost-benefit analysis, innovative strategies for financing
August 24-28, 2020: Eurosoil 2020. Geneva, Switzerland. The European Confederation of Soil Science Societies organizes this event to bring together leading research scientists working on soil related topics and stakeholders dealing with issues of public concern, such as soil degradation and consequences of climatic changes. The 2020 theme of "Connecting People and Soil" aligns with selected sustainable development goals of the United Nations.
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