Environmental Factors and Health
Soil is the media for the production of food and clothing materials and the reservoir of drinking water. It is also the media on which we settle to live. Therefore, a clean soil environment is essential to human health.
The soil is constantly influenced by human activities in the form of agriculture, industrial activity, extraction of various minerals, landfills, deposition of airborne pollutants from heat and power production, industrial activities, traffic, waste incineration etc. Deterioration of the soil quality or contamination with chemical substances harmful to human health may be the consequence of this influence.
Apart from deliberate soil treatments and depositions (e.g. use of pesticides and deposition of waste in dumpsites), the influence is mainly an undesired result of a large range of activities, which include both effects from spillage and leakage of chemicals and deposition of airborne contaminants.
This chapter will focus on the regulations connected to environmental factors in soil, which potentially have an impact on human health.
Environmental factors in soil are numerous. The primary factors of concern in Denmark are summarised in table 6.1.
Much soil is contaminated due to former land use. Industrial and trade activities have over time lead to a large number of contaminated sites. Inappropriate handling of chemical substances and oil-products has caused spillage and leakage of chemicals and oil-products to the soil environment within a wide range of activities:
Production of chemical products, e.g.
Heat and power production, e.g.
Manufacturing processes where chemicals are used as ancillary materials, e.g.
Final consumption of chemical substances, e.g.
Other contamination of soil has occurred in connection with storage of liquid fuels related to petrol retail sales and depots, industrial and trade activities (e.g. tile works and glass production) and oil-heated private homes.
Most of these sites are situated in urban areas, which implies that a part of the population potentially may be affected by problems arising from contaminated soil. Furthermore, many residences have been built on such sites at a time when general acknowledgement of soil contamination was lacking, and therefore may be without any protection against the harmful substances.
The total number of sites that can be affected of former industrial and other polluting activities is estimated to include about 30,000 of which 14,000 are expected to be contaminated. The counties have identified most of these sites since the first legislation came into force in 1983. Public investigations of about 8,000 have lead to the registration of about 6,000 sites of which about 1,400 have been deregistered or released for specific use. As per 31/12 1999 the total number of registered contaminated sites in Denmark amounted to 4,940.
Of these 4,940 sites, 1,830 are prioritised sites expected to be included in the public clean-up effort. 617 sites hereof are used for housing or similar, 1,022 are sites that threaten the groundwater and are situated in particularly valuable water abstraction areas, and the remaining 191 sites are both threatening the groundwater in particularly valuable water abstraction areas and used for housing purposes.
In 1999 1,115 sites were cleaned up. 79 projects were financed by public funds, 570 sites were subjected to voluntary clean-up, and 506 sites were cleaned up under other schemes, primarily the scheme of the Oil Industrys Environmental Fund.
Furthermore, the deposition of industrial and domestic waste taking place prior to the regulation of waste deposition has resulted in nearly 2,000 contaminated sites (of which the majority are included in the above mentioned registered contaminated sites). Most of the dumpsites contain organic materials producing inflammable gasses (primarily methane), which might pose a risk for explosion when migrating into houses. Such a case with fatal outcomes has occurred in Denmark.
The intensive exploitation of agricultural land affects the quality of the soil. Farmland is affected by the application of pesticides and by the spreading of sludge and fertilisers. About 20,000 km2 are cultivated in Denmark. It is estimated that the annual treatment of farmland with sludge affects about 300 km2. The application of pesticides to farmland is mainly considered being a problem due to the risk of leaching to surface- and groundwater. However, the use of sludge may lead to the accumulation of heavy metals in the topsoil, which can be a direct or indirect source of human exposure.
Diffuse airborne contamination
The soil quality, especially in urban areas, is affected by diffuse airborne contamination due to emissions from traffic and incineration of waste and combustion of fuels for heat and power production. The influence of airborne pollutants has resulted in diffuse contamination of large districts in urban areas. Some of these are considered to pose a risk to humans (in particular children) due to the content of heavy metals (primarily lead) and poly-aromatic hydrocarbons (PAH) in the topsoil. A total area of up to 200 km2 is expected to be affected by the deposition of airborne pollution. Out of these, approximately 20 km2 are estimated to be used for sensitive land use such as housing, kindergartens and public playgrounds.
Uncontrolled disposal of contaminated soil
Finally, uncontrolled use and disposal of soil has lead to spreading of contaminated soil, notably in gravel pits, agricultural lands and in urban areas.
The extent of human exposure to environmental factors (harmful chemical substances) from soil depends on the land use, the concentrations in the soil media, and the risk of contamination of other environmental media (groundwater and air).
The ways of exposure to environmental factors from the soil environment can be divided into direct exposure and indirect exposure.
Direct exposure to substances in the soil:
In Denmark, the most significant exposure routes in relation to regulatory measures are generally considered to be
Risk management are based on these exposure routes, as the soil quality criteria are derived with respect to the direct exposure to soil (ingestion and/ or skin contact with soil), the air quality criteria are related to the evaporation from soil to indoor air and drinking water quality criteria are related to ingestion of drinking water. Only few soil quality criteria (e.g. DDT and cadmium) have been derived to account for contamination of crops and the following exposure through consumption hereof.
Primary exposure routes are summarised in figure 6.1.
The level of protection is primarily determined by guidelines for risk assessment and by use of health based quality criteria. The purpose is to prevent any health hazards in the human population caused by chemicals as pollutants. In order to fulfil this objective the precautionary principle is used in risk assessment, in derivation of health based quality criteria using safety factors and in designing the level of protection to the most sensitive target group: Small children. The resulting level of protection is considered high compared on an international scale as elaborated in the following sections.
In November 1998, a guideline on Remediation of Contaminated Sites was issued (DEPA 1998.). It provides a detailed description of the management of contaminated sites including guidelines for risk assessment, field survey methods, collection of samples, site characterisation, and implementation and control of remedial actions.
Guidance for risk assessment is an important tool in evaluation of soil contamination because the routes of human exposure are complex. The risk assessments concerning contaminated soil are primarily aimed at:
Usually, risk assessments are based on contaminant concentrations, comparing them with the quality criteria for soil, groundwater/drinking water or air. If the concentration level of a specific contaminant is found to exceed the relevant criterion, the contamination of the site is considered unacceptably high (if the concentration is at the same level as the quality criteria, further evaluations may be necessary). This will result, either in further field investigations to improve the initial risk estimate, in restrictions on landuse, or in remedial action.
Assessing the risk of soil ingest, skin contact and inhalation of dust particles is based on the landuse and the accessibility of the contaminated soil to human exposure (e.g. is the contaminated soil accessible or covered by clean soil, grass, pavement etc.).
Humans are especially exposed to injurious substances on lands used for sensitive purposes like playgrounds, day-care centres and residential gardens including household gardens. Especially children are at risk as they often come into close contact with the soil and often ingest soil directly (small children) or become exposed via contaminated toys and fingers. Moreover, some substances exert their toxic effects via absorption through the skin.
Sites registered in the Danish Inventory of Contaminated Sites are prioritised according to the need for remediation. Since nearly all drinking water in Denmark derives from groundwater, groundwater protection has a very high priority. Quality criteria for groundwater shall thus ensure that the water, when it reaches the consumer, complies with the drinking water quality criteria. Generally, lower priority is given to surface water.
Assessing the risk of ground water contamination is based on calculations of contaminant transport by infiltration. The most significant factors in the calculations are as follows:
The risk assessment is based on the principle that the groundwater zone containing the highest concentration must comply with the drinking water/ groundwater quality criteria.
Assessing the risks from volatile soil contamination in relation to indoor air is based on calculations of contaminant transport by diffusion through pore spaces in the unsaturated zone and transport by convection into buildings through diffusion and gaps in concrete floors. If the estimated contaminant concentration in indoor air exceeds the air quality criterion, the contamination is considered unacceptable.
For the guidance of public authorities the Danish EPA has laid down provisions as to the quality of soil, air and water. For the protection of human health, the quality criteria for chemical pollutants are set at a level at which exposure to the media is not considered to have any adverse effect on human health. That means that the level of the quality criteria is considered to represent a safety level. Thus, when a quality criteria is exceeded to a minor extent it does not mean that a danger level is reached, rather it should be interpreted as an undesirable reduction of the safety level.
Soil quality criteria are derived to protect against harmful effects from direct exposure to soil. In parallel to this, air quality criteria are derived to account for the evaporation of volatile contaminants into indoor air, and ground water/ drinking water quality criteria are used in connection with wash-out and contamination of the groundwater. The contamination is judged tolerable if none of the relevant media oriented quality criteria is exceeded. If for example a contamination is at or below the level of the soil quality criteria, then the area can be used for most sensitive uses. If, at the same time, the contamination level in groundwater is exceeding the ground water quality criteria, then the contamination is considered unacceptable in relation to protection of the groundwater. Thus, compliance to the soil quality criteria does not automatically secure the contamination of the other media i.e. the degree of evaporation to indoor air or the wash out into the groundwater. Criteria values have been published in the guideline on Remediation of Contaminated Sites (DEPA 1998) and in a report on toxicological quality criteria (DEPA 1995). An updated compilation of the specific quality criteria is given in Appendix 1.
Soil quality criteria
Soil quality criteria are derived with respect to the most sensitive uses of the soil i.e. use for domestic gardens, kindergartens or playgrounds. The intention is to protect small children, as children is considered to be the most heavily exposed group (ingestion of soil, hand - mouth contact), but also because children for several chemical pollutants may be more biological susceptible than adults. The calculation of the soil quality criteria is based on a standard scenario consisting of a child weighing 10 kg who ingests 0,2 g soil per day as an average. For acutely toxic substances, isolated ingestion of 10 g of soil is considered. Average skin contact is set to 1g soil to consider substances with high skin permeability. Another issue in the setting of soil quality criteria is the bioavailability of the substance from the soil. For most substances very little is known and only in one specific case (the quality criteria for nickel) data concerning bioavailablity have been used and influenced the final value. For further details, see Appendix 1, where principles and further details in connection with the calculation of health based quality criteria are described.
In urban areas, the quality criteria is generally exceeded for several substances (especially lead and PAH's). Therefore, a new type of guideline value for soil used for sensitive purposes is introduced. It is called the "cut off value". If the cut off value is exceeded at sites used for residential use, childcare institutions or public playgrounds, remediation must be performed. If the concentration of a contaminant is in the range between the cut off value and the quality criteria, and the site is used for sensitive purposes, the local authorities inform and advise the public, the landowner and the users of the site. The purpose is to establish hygienic measures and soil-exposure reduction measures in order to reduce the actual exposure and thereby obtain the same level of protection as normally obtained at the soil quality criteria. This is called the "advice to residents interval" as illustrated in figure 6.2. The main principle is to avoid bare soil surfaces that otherwise could lead to direct soil exposure of children, and advice is given on measures to avoid bare soil. This also has the consequence that, although investigations has shown that only minor amount of contaminants can be measured in vegetables grown in slightly contaminated soil, it is recommended not to grow vegetables in contaminated soil, because it is nearly impossible to grow them without having bare soil, which could lead to exposure of humans, especially children.
Cut off values can only be used for immobile and rather persistent chemicals and are only set for 10 metals and polyaromatic hydrocarbons.
Examples of quality criteria for soil and cut off values are summarised in table 6.2.
It should be noticed, that the cut off value and the quality criteria are identical in cases where the quality criteria have been set in order to protect against acute toxic effects, whereas the cut off value may be up to ten times higher than the quality criteria in cases where the soil quality criteria are set to protect against toxic effects from chronic exposure. The rationale for this is that information to the public and risk reduction measures in general are considered to have an effect in reducing the average exposure of the children. However, these measures may not necessarily secure against single occasions with high oral soil exposure. That means that the cut off value can not be increased compared to the quality criteria, if acute toxic effects have been the basis for the setting of the soil quality criteria.
Quality criteria for evaporation
Assessing the risks from volatile soil contamination in relation to indoor air is based on calculations of contaminant transport by diffusion through pore spaces in the unsaturated soil zone and transport by convection into buildings through diffusion and gaps in concrete floors. If the actual geological and building parameters are not known, standard parameters are used (DEPA 1998). If the estimated contribution to indoor air from evaporation from soil exceeds the air quality criterion for evaporation, the contamination is considered unacceptable.
Danish air quality criteria for evaporation is summarised in Appendix 1. The air quality criteria are also used in outdoor air as emission values to control the emission from industry (see section 5.2.1).
Quality criteria for ground water/ drinking water
The objective is to protect groundwater as a drinking water resource, irrespective of whether abstraction borings are located in the area or not. Drinking water is dealt with in chapter 7 and quality criteria for groundwater/ drinking water are presented in Appendix 1.
Quality standards for waste products
Some provisions have been laid down on the use of sludge, sewage, compost, ash from biomass and other waste products for agricultural purposes (Statutory Order on Sludge no. 49 of 20 January 2000 and Statutory Order on Bioash no. 39 of 20 January 2000). These regulations define certain quality standards for the maximum concentration of organic contaminants and heavy metals in waste products to be distributed on agricultural land. These Danish quality standards are substantially lower than given in the EU Directive on Sludge (86/278/EEC), which further more only covers sludge and only gives quality standards for heavy metals.
The concentration of heavy metals in soil may not exceed certain contents if waste products shall be applied. The quality criteria for agricultural soil are defined for seven heavy metals.
Source: Statutory Order no. 49 of 20 January 2000 on use of waste products for agricultural and related purposes. (the "Sludge Order").
The primary objective of regulation on contaminated soil is to prevent, eliminate or reduce soil contamination and to hinder or prevent harmful impact of soil contamination on human health, groundwater and the general environment. The precautionary principle is used both in setting quality criteria (principles are explained in appendix 1) and in guidelines for performing risk assessments.
In the early 1970s, authorities in Denmark became aware of the potential problems with some contaminated sites, especially landfills containing chemical waste. The uncovering of buried waste in a number of cases during the 1970s led to enactment of the first legislation dealing with contaminated sites (The Chemical Waste Deposit Act of 1983). During the 1980s it also became clear that landfills containing household waste, and industrial activities, could pose a risk to man and the environment. As a consequence the legislation was revised (The Waste Deposit Act of 1990) in order to include all types of contaminants. Realising that contamination could also result from airborne and other diffuse sources, the Soil Contamination Act was adopted in 1999. Thus, the Soil Contamination Act covers all contamination in soils, irrespective of the time and place of contamination.
However, the act does not apply to soil affected by agricultural application of sludge, fertiliser, and pesticides, etc.
Preventive measures are primarily met in the permits required for any polluting activity as defined in chapter 5 of the Environmental Protection Act and in the incentives for application of cleaner technology. Similarly, rules are set up for regulation of storage of liquid fuels.
General preventive measures are also conducted in the regulation of the use of toxic chemical substances (lead additives in petrol, cadmium and mercury in batteries, chlorinated solvents etc.) and waste management (incineration, separation of waste products, recycling, etc.).
The soil contamination act
The Soil Contamination Act83 entered into force on 1 January 2000, for certain provisions under the act a bit later. The act replaces Act on Waste Deposits.
The Environmental Protection Act regulates the protection of the ground water. It prohibits the discharge of polluting substances on the ground. However, this is not sufficient as there are already a lot of existing waste deposits or areas where the soil is contaminated in Denmark, very often they are situated on areas where there is or have been industry or other polluting activities. The Act on Soil Contamination covers these problems.
Mapping of contaminated areas
In 1990, the counties systematically started investigating all sites that were being or had been used for activities presenting a potential contamination risk.
As a consequence of the Soil Contamination Act, a new system of mapping of contamination is introduced. According to the act, the county council shall carry out mapping, possibly through technical investigations, of contaminated areas in co-operation with the municipal council.
Soil management system
Before transporting soil from a property mapped as contaminated, or mapped as potentially contaminated (because it is in use or has been in use for activities that might contaminate the soil), a notification must be sent to the municipality. The municipality will in case the municipality disagrees with the proposed disposal - instruct the applicant on how to dispose the soil and on the needed requirements for documentation of the soil quality.
Any receiver of soil excavated anywhere shall ensure that the soil does not harm the groundwater, human health, and the general environment.
Liability and payment of damages
Danish environmental legislation is based on the polluter pays principle. The liability for soil contamination can be considered as both a legal and an economic instrument. The consequences of soil contamination as to payment of damages and restoration can be solved in accordance with:
During the 1990s, several lawsuits revealed that strict liability for contaminated sites cannot be applied within Danish civil law. The Supreme Court ruled against the Ministry of the Environment and Energy in a number of cases where it could not be proved that the polluter was acting in bad faith at the time the pollution occurred. A ruling from the Supreme Court in 1992 states that the normal time limit for liability in cases of soil contamination is 20 years. As a consequence, a polluter cannot be held liable for contamination that took place more than 20 years ago, whether the polluter acted in bad faith or not. As a consequence, the Soil Contamination Act provides for a number of significantly strengthened enforcement powers, primarily to be applied in relation to pollution occurring after January 1, 2001.
Other regulation of soil contamination
The spreading of sludge and uses of fertilisers and pesticides in agriculture are regulated through statutory orders and through the Act on Chemical Substances and Products.
The registration (approval) and use of pesticides is regulated by the Act on Chemical Substances and Products and in more detail by the provisions of the Statutory Order on Pesticides (Statutory Order no. 241 of 27 April 1998 with revisions of 20 December 1998, 25 September 1999 and 5 May 2000). This legislation regulates which pesticides are permitted for use in Denmark and for what purposes, but does not define maximum levels of total loads or frequency of use of pesticides at field level for the approved purposes. Such general goals to reduce total agricultural pesticide consumption and use have been stipulated in the Pesticide Action Plans I and II passed by the Danish Parliament in 1987 and 1999, respectively.
Waste products such as municipal sewage sludge, industrial sludge and compost from domestic and industrial organic solid waste can, under certain preconditions, be used for fertilising and other soil amelioration purposes in agriculture, horticulture and forestry. Such uses of waste products are regulated by Statutory Order no. 49 of 20 January 2000 on use of waste products for agricultural and related purposes (the "Statutory Order on Sludge") in which maximum levels of 8 heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) and 4 organic chemical contaminants (DEHP, LAS, NPE, PAH) as well as maximum application amounts are stipulated. Furthermore, the statutory order contains soil quality criteria that must not be exceeded as a result of the use of sludge or other waste products (manure and garden waste are not comprehended by the statutory order).
Quality criteria for soil, evaporation to indoor air and for groundwater/ drinking water, all aiming at the protection of human health, are among the primary regulatory instruments determining the level of human protection as described in section 6.2.2.
Enforcement notices to the polluter
The Soil Contamination Act defines a set of rules on enforcement notices to the polluter.
An enforcement notice on cleaning up pollution can be given by the municipal or county authority.
The concrete enforcement notice concerning the cleaning up of pollution is given to the polluter, and this can be given irrespective of how the pollution has happened. It is furthermore without importance whether the addressee of the enforcement notice owns the polluted premises. If more than one polluter is involved in pollution, a compliance order must be given to all of them. The authority, which has conducted a cleaning up, may sue the responsible persons and businesses for the costs of remedying environmental contamination.
If the addressee of the enforcement notice cannot freely dispose of the polluted premises, the authorities must give an enforcement notice to the person who can dispose of the real estate. He can be ordered to tolerate that cleaning up or other measures are taken at the cost of the polluter.
The enforcement notice must be registered on the real estate at the expenses of the addressee of the order. Enforcement notices concerning the operation of a business must be binding also to future entrepreneurs. An enforcement notice cannot be given if 30 years or more have elapsed from the time of ceasing of the activity, which caused the pollution.
Mapping of contaminated sites
As a consequence of the Soil Contamination Act, a new system of mapping of contamination is introduced. According to the act, the county council shall carry out mapping, possible through technical investigations, of contaminated areas in co-operation with the municipal council.
A site is mapped if it is contaminated or if it is highly probable that the site contains soil contamination that may have a harmful impact to humans and the environment. The information on the mapped sites is entered into the Land Register.
A guideline on Mapping of Contaminated Sites has been issued in 2000. It will provide a detailed description of the mapping procedures for contaminated sites and sites supposed to be affected by present or former uses or vicinity to other pollution sources.
Approval, obligation of notification, obligation to act, etc.
According to the definitions in the appendix to chapter 5 in the Environmental Protection Act, some activities need prior approval or permit before they can be carried out. Environmental and/or health related norms are typically laid down in approvals or permits to carry out a certain activity.
Some activities are permitted if they have been notified in advance - they do not need prior approval as such.
For some activities the entrepreneur shall notify the authorities if there is a risk for serious damage on environment or health.
Restrictions on land-use
Owners of sites mapped as contaminated (or potentially contaminated) are subjected to a number of restrictions on land use. Before initiating building or construction work on the site, an application should be sent to the regional council. A permit will often be given on the condition that the owner or user carries out the required pollution investigations on his own account. Building or construction permits relating to contaminated soil are not required for mapped industrial sites, if the use of the site is not changed. However, the municipal authorities must be notified if soil is removed from the site.
People who live in slightly contaminated areas will receive advice on soil-exposure reduction measures. A guideline "Advice to residents in slightly contaminated areas" has been issued in 2000. In the case of areas that are accessible for the general public it is possible to give an enforcement notice to the owner on measures to secure that contact with contaminated soil is avoided.
With respect to contaminated soil, special economic instruments do not play a key role in the regulation of behaviour aimed at preventing soil contamination. However, the principle of liability can be considered as such, given the economic consequences for any polluter if soil pollution occur.
Taxes are used in two cases:
With the aim of reducing pesticide use mainly in agriculture and public and private cleaning of roads and gardens, pesticides are now subject to taxation.
For information about the Pesticide tax, refer to chapter 10.
The revenue of these taxes is funding a research programme for the environ-mental and health effects of pesticides.
Some clean-ups can be financed through the Water Fund provided for in taxes on drinking water with the double aim of protecting the limited water resources by reducing the drinking water consumption and funding of remedial actions on contaminated borings and water abstraction zones.
The Oil Industrys Environmental Fund
In the wake of the energy crisis in 1973, a series of structural changes followed, take-overs, and rationalisations within the oil industry leading to close down of many petrol retail sites. In 1990, 6,000 retail sites had been closed down leaving an enormous remediation problem.
It was foreseen that enforcement notices to the owners could be in vain since no infringement of the environmental law had occurred, and which would involve the state to cover the expenses.
The amount of public money to be used for cleaning up contaminated soil was not large enough and consequently, the organisations of oil importers as well as retail dealers made in 1992 an agreement with the environmental authorities concerning voluntary clean-ups called "The Oil Industrys Environmental Fund". The goal of this fund is to finance efforts to clean-up contaminated petrol retail sites. It is clearly assumed that all companies, whether or not they had an interest in utilising the environmental fund, will be covered by the contract. The assumption is justified by the relationships in the industry that no company could tolerate unequal competition. The consumers pay for the soil clean-ups through a price increase of 0.05 DKK/l. This produces an annual budget for investigation and/or remediation of approximately 300 sites.
In total 9,660 retail sites have been notified for clean-ups by the Fund. Of these 2,200 have been cleaned up until 1 August 2000.
Programme for Development of Technology Soil and Groundwater Contamination
In 1996, a programme for development of clean-up and remediation technologies relating to soil and groundwater contamination was set up primarily to stimulate the public authorities to apply innovative methods and replace standard excavation and replacement of contaminated soil.
Since the programme was launched, about 60 projects have been initiated, half of them to support testing of different remediation technologies. The other half supports development projects dealing with different remediation technologies, or enhances general knowledge on soil contamination.
Insurance scheme for oil tanks used for domestic heating
A special rule has been introduced regarding owners of oil tanks with a capacity below 6,000 litres, used for domestic heating. Strict liability in these cases only applies if contamination takes place after March 1, 2000. These more strict rules on the responsibility of owners of private oil tanks are combined with a compulsory insurance programme. All the oil companies supplying heating oil have established a joint insurance scheme. All owners of oil tanks used for domestic heating with a capacity below 6,000 litres are automatically covered by the insurance scheme.
For oil contamination, which is not covered by the scheme, the authorities can issue enforcement notices to the owner of the oil tank.
Land depreciation scheme for remediation of contaminated residential properties
Frequently, soil pollution in itself has not only environmental impacts, it also has financial consequences. One of the biggest economic problems relating to contaminated soil is the number of sites which are registered as contaminated and the loss it represents for the landowners.
A special clean-up system for landowners was introduced in 1993 with the Act on Economic Blight to Family Housing on Contaminated Land (The Loss of Value Act). After the enforcement of the Soil Contamination Act, this clean up system is continued within the Act under the title "The Land depreciation Scheme for House Owners". By paying a minor contribution, the landowner can initiate a publically financed clean-up.
An annual average of about 40 properties have been cleaned up under the scheme since 1994.
The primary actors concerning the regulation of soil contamination are listed in table 6.4. For general descriptions of the mentioned actors please refer to chapter 3.
The health-based regulation of soil contamination in Denmark has the objective to avoid any harmful impact on public health. In order to fulfil this objective the choice of risk assessment procedure and procedures for the derivation of health based soil quality criteria has been made considering the precautionary principle. Hence, the soil quality criteria are directed towards protection of the most vulnerable target group: Small children.
Except for a fatal case of explosion of landfill gas there are no recognised chases of harmful impact of soil contamination on public health. A great effort is invested in mapping of contaminated sites and in remediation and/or exposure prevention once contamination is recognised, following the above principles. However, there is a time lag before all potentially contaminated sites are investigated and human exposure prevented, and new contamination cases will eventually appear. Mapping of contamination from diffuse sources is furthermore by nature more difficult, especially in urban areas, but also in agricultural soils (e.g. originating from soil treatments with pesticides, fertilisers or waste products). Therefore it is possible that some human exposure occur above the levels set out in the regulation, but this risk is minimised by the mapping priorities, starting with sites with the most sensitive land-use such as residential use, childcare institutions or public playgrounds or sites where groundwater is threatened. Furthermore, limited exceeding of the soil quality criteria is not considered to endanger human health, but should rather be considered as an undesired reduction in safety margin.
Important challenges are therefore to optimise the mapping and remediation with respect to human health and groundwater protection also taking diffuse contamination into account. Risk communication is also an important tool in minimising human exposure and the sense of insecurity that may follow. Furthermore, prevention of new soil contamination is a prime issue in establishment of new installations and in control of the existing.
New health related issues concerning soil contamination will inevitably occur in the future, related to new sources of contamination or new knowledge of human health effects of chemicals. Another trend to be aware of is the increasing use of waste products as fertilisers on agricultural soils, which will introduce a broad spectrum of chemicals to the soil of which we do not presently know enough about fate and possible human effects.
Based on our present knowledge, the regulation in broad terms seems to be sufficient to obtain the objective of preventing harmful impacts on public health.
It is important to gain new knowledge on remediation techniques and exposure prevention in order to optimise the use of the economic resources. Also more knowledge on fate, mobility, bio-availability and human effects of chemicals from soil contamination are needed in order to confirm and secure the high level of protection.
DEPA (1998): "Remediation of contaminated sites, guideline no. 6".
DEPA (1995): "Toxicological quality criteria for soil and groundwater, report no. 12".
DEPA (2000): "Advice to residents in slightly contaminated areas, guideline no 7/2000".
DEPA (2000): "Mapping of contaminated areas, guideline (draft)/2000".
Act no. 370 of 2 June 1999 on Soil Contamination.
Act no. 256 of 12 June 2000 amending the act on Chemical Substances and Products.
Act no. 698 of 22 September 1998 on Environmental Protection
Statutory Order no. 39 of 20 January 2000 on use of ash from gasification and combustion of biomass and biomass waste for agricultural and related purposes (the "Statutory Order on bioash")
Statutory Order no. 49 of 20 January 2000 on use of waste products for agricultural and related purposes (the "Statutory Order on Sludge")
Statutory Order no. 829 of 24 October 1999 on application, establishment and operation of oil tanks, tubing and pipelines.
Statutory Order no. 241 of 27 April 1998 on Pesticides (with revisions of 20 December 1998, 25 September 1999 and 5 May 2000).
The Food Directorate's Statutory Order no. 659 of 14 July 1997 on maximum residue levels of pesticides.
Directive 86/278/EEC (1986): "On protection of the environment, especially the soil, in connection with use of sludge from wastewater treatment plants for agricultural purposes".
83 Act No. 370 of 2 June 1999.