Remediation

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Template:Environmental technology Generally, remediation means giving a remedy. In this article, the term refers to the removal of pollution or contaminants from environmental media such as soil, groundwater, sediment, or surface water for the general protection of human health and the environment or from a brownfield site intended for redevelopment. Remediation is generally subject to an array of regulatory requirements, and also can be based on assessments of human health and ecological risks where no legislated standards exist or where standards are advisory.

Remediation in terms of new media, is the representation of one medium in another (Jay David Bolter and Richard Grusin 1999). Template:TOCright

 

Contents

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Remediation standards

In the USA the most comprehensive set of Preliminary Remediation Goals (PRGs) is from the EPA Region 9, although the Canadian EPA also has a comprehensive spreadsheet of PRG's. A set of standards used in Europe exist and is often called the Dutch standards. The European Union (EU) is rapidly moving towards European wide standards, although most of the industrialised nations in Europe have their own standards at present

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Site assessment

Once a site is suspected of being seriously contaminated there is a need to assess the contamination. The historical use of the site and the materials used and produced on site will guide the assessment strategy and type of sampling and chemical testing to be done. Often nearby sites owned by the same company or which are nearby and have been reclaimed, levelled or filled are also contaminated even where the current land use seems innocuous. For example, a car park may have been levelled by using contaminated waste in the fill. Also important is to consider off site contamination or nearby sites often through decades of emissions to soil, water, and air. Ceiling dust, topsoil, surface and groundwater of nearby properties should be tested both before and after the remediation. This is a controversial step as:

  1. No one wants to have to pay for the clean up of the site;
  2. If nearby properties are found to be contaminated it may have to be noted on their property title, potentially affecting the value;
  3. No one wants to pay for the cost of assessment.

Often corporations which do voluntary testing of their sites are protected from the reports to environmental agencies becoming public under Freedom of Information Acts, however a Freedom Of Information inquiry will often produce other documents that are not protected or will produce references to the reports.

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Funding remediation

In the US there has been a mechanism for taxing polluting industries to form a Superfund to remediate abandoned sites, or to litigate to force corporations to remediate their contaminated sites. Other countries have other mechanisms and commonly sites are rezoned to "higher" uses such as high density housing, to give the land a higher value so that after deducting clean up costs there is still an incentive for a developer to purchase the land, clean it up, redevelop it and sell it on, often as apartments (home units).

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Remediation technologies

Remediation technologies are many and varied.

Remediation technologies used in the 1970's-1990's consisted primarily of excavation and disposal, and groundwater "pump and treat". Since 2000, new "in situ oxidation" technologies have become popular, for remediation of a wide range of soil and groundwater contaminants. Remediation by oxidation involves the injection of strong oxidants such as peroxide, ozone gas, potassium permanganate or pursulfates.

Some technologies are controversial, particularly anything involving relative low temperature incineration because of the risks of dioxins released in the atmosphere through the exhaust gases. For this reason remediation proponents often use terminolgy such as thermal oxidizer and direct thermal desorption to minimise the risk becoming emotive such that the community begins to imagine incineration risks. Controlled, high temperature incineration with filtering of exhaust gases however should not pose any risks.

The treatment of environmental problems through biological means is known as bioremediation and the specific use of plants for example by using phytoremediation.

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Community consultation and information

In preparation for any significant remediation there should be extensive community consultation. The proponent should both present information to and seek information from the community. The proponent needs to learn about "sensitive" (future) uses like childcare, schools, hospitals, and playgrounds as well as community concerns and interests information. Consultation should be open, on a group basis so that each member of the community is informed about issues they may not have individually thought about. An independent chairperson acceptable to both the proponent and the community should be engaged (at proponent expense if a fee is required). Minutes of meetings including questions asked and the answers to them and copies of presentations by the proponent should be available both on the internet and at a local library (even a school library) or community centre.

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Incremental health risk

Incremental Health Risk is the increased risk that a receptor (normally a human being living nearby) will face from (the lack of) a remediation project. The use of incremental health risk is based on carcinogenic and other (e.g., mutagenic, teratogenic) effects and often involves value judgements about the acceptable projected rate of increase in cancer. In some jurisdictions this is 1 in 1,000,000 but in other jurisdictions the acceptable projected rate of increase is 1 in 100,000. A relatively small incremental health risk from a single project is not of much comfort if the area already has a relatively high health risk from other operations like incinerators or other emissions, or if other projects exist at the same time causing a greater cumulative risk or an unacceptably high total risk. An analogy often used by remediators is to compare the risk of the remediation on nearby residents to the risks of death through car accidents or tobacco smoking.

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Emissions standards

Standards are set for the levels of dust, noise, odour, emissions to air and groundwater, and discharge to sewer or waterways of all chemicals of concern or chemicals likely to be produced during the remediation by processing of the contaminants. These are compared against both natural background levels in the area and standards for areas zoned as nearby areas are zoned and against standards used in other recent remediations. Just because the emission is emanating from an area zoned industrial doesn't mean that in a nearby residential area there should be permitted any exceedances of the appropriate residential standards.

Monitoring for compliance against each standards is critical to ensure that exceedances are detected and reported both to authorities and the local community.

Enforcement is necessary to ensure that continued or significant breeches result in fines or even a jail sentence for the remediator.

Penalties must be significant as otherwise fines are treated as a normal expense of doing business. Compliance must be cheaper than to have continuous breeches.

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Transport and emergency safety assessment

Assessment should be made of the risks of operations, transporting contaminated material, disposal of waste which may be contaminated including workers' clothes, and a formal emergency response plan should be developed. Every worker and visitor entering the site should have a safety induction personalised to their involvement with the site.

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Impacts of funding remediation

The rezoning is often resisted by local communities and local government because of the adverse impacts on the local amenity of the remediation and the new development. The main impacts during remediation are noise, dust, odour and incremental health risk. Then there is the noise, dust and traffic of developments. Then there is the impact on local traffic, schools, playing fields, and other public facilities of the often vastly increased local population.

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Example of a major remediation project

For an example of a complete rezoning by a state government over the opposition of local government and local communities of former chemical plants to fund remediation to allow for redevelopment for high density residential, retail and office development in Australia see http://rhodesnsw.org

In this case the proposed rezoning, remediation and redevelopment has a wealth of material available through the internet from:

List of sources of publicly available material, most accessible through the internet and from http://rhodesnsw.org:
  1. Numerous investigations and reports by Australian and International consultants
  2. For the former Union Carbide site, a previous remediation by excavation and containment in a clay capped sarcophagus, separated from the Bay by a bentonite wall.
  3. A Parliamentary Inquiry by the Upper House of the Parliament of New South Wales, a state of Australia;
  4. Two Commissions of Inquiry, one for each of the major dioxin contaminated sites, both contaminated by the operations of Union Carbide;
  5. Resolutions by the relevant local government bodies (originally Concord council and after the Municipality of Concord was merged with Drummoyne Council to form the City of Canada Bay, by that Council);
  6. Campaigns by local residents' groups, Greenpeace Australia, Nature Conservation Council of NSW, and Inner West (of Sydney branch of the) Greens
  7. published submissions by Planning NSW and Environmental Protection Agency of NSW;
  8. Comprehensive Environmental Impact studies published in digital format and available on CD from Planning NSW.

This rezoning, remediation and redevelopment of land contaminated by Union Carbide, ICI and others also involves the remediation of a strip of dioxin contaminated sediments in Homebush Bay, New South Wales. The Homebush Bay area was home to the main events of the Sydney 2000 Summer Olympics. The soil contamination was addressed in the Commission of Inquiry into the Lednez site formerly owned by Union Carbide, but not to the satisfaction of local community activists.

The remediation of Homebush Bay is important because of its impact on the food chain which extends through benthos not only to local protected and threatened species of birds, but also to JAMBA and CAMBA protected species and species which use other Ramsar-protected wetlands. Ultimately human health is impacted through the food chain. Homebush Bay has a complete fishing ban, there is a commercial fin fishing ban west of the Gladesville Bridge, and based on submissions of the remediator and NSW Waterways and EPA the complete fishing ban ought be extended to the whole of the Parramatta River west of Homebush Bay and at least as far East as the Ryde Traffic Bridge.

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See also

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Wikipedia links

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Legislation about remediation

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Environmental groups with information

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Environmental protection agencies

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Major remediation projects

  • http://rhodesnsw.org (Rhodes, NSW, Australia - Union Carbide - dioxin - High density residential, retail offices, open space)
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External links

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