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Assessment of the Impact of an EC Directive on Priority Substances under the WFD on the Current Regulation of Contaminated Sites

4 Step 2 - Number of sites in Denmark constituting a risk

• 4.1 Geographic distribution of areas near surface waters
  • 4.1.1 Areas close to surface waters
• 4.2 Geographical distribution of sites
• 4.3 Number of major sites
• 4.4 Number of minor sites
  • 4.4.1 Sites contaminated with HCH/lindane
  • 4.4.2 Sites contaminated with nonylphenol/octylphenol
  • 4.4.3 Sites contaminated with tributyltin compounds
  • 4.4.4 Sites contaminated with trichlorobenzene
  • 4.4.5 Sites contaminated with pentachlorophenole
  • 4.4.6 Sites contaminated with trichloromethane
  • 4.4.7 Waste dumps
• 4.5 Total estimate on sites of relevance
  • 4.5.1 Sites at risk of exceeding the EQSs
  • 4.5.2 Sites of relevance regarding phase-out of PHS

4.1 Geographic distribution of areas near surface waters

Facts about Danish area and surface water are shown in box 4.1.

Text box 4.1
Facts about Danish area and surface waters. Data have been collected from ¹: Danish EPA (1994) and ²: DST (2006).

As shown in section 3.4, Denmark is divided into three parts, geologically viewed:

• West of 'hovedstilstandslinien'
• Areas with high situated limestone
• Remaining areas east of 'hovedstilstandslinien'.

The area west of 'hovedstilstandslinien' is characterised by consisting mainly of glacial water deposits.

The area constitutes, cf. text box 4.1, approximately 23 % of the total Danish area. Text box 4.1 also states that the total length of water courses west of 'hovedstilstandslinien' is also approximately 23 %. On the basis of this, it is assumed that water courses, lakes and coastal areas are evenly distributed.

The area east of 'hovedstilstandslinien' is characterised by mainly being composed of moraine/till sediments. The area constitutes the remaining part of Denmark i.e., approximately 72 % of the total Danish area.

4.1.1 Areas close to surface waters

Areas close to surface waters are in this report defined as areas closer than 100 m to inland waters and closer than 500 m to costal waters. The total area close to surface waters can therefore be calculated as follows:

The areas close to water courses are approximately 4,000 km². The total length of water courses included in the nature protection act is approximately 20,000 km². On both sides of the water course, is a border of 100 m.

Areal_Waterc. = (20.000km · 100m) · 2 = 4,000km²

The areas close to lakes are approximately 2,250 km². If it is presumed that a lake has the shape of an ellipse where the shortest radius is 100 m and the longest radius is 200 m, then the area of the 100 m wide border near the lake can be calculated as an ellipse with the shortest radius being 300 m and the longest 400 m, minus the area of the lake of 0.07 km².

Areal_Lakes = (π · (100m + 2 · 100m) · (200m + 2 · 100m) - 0,07) * 7.200 = 0,3km² · 7,200 = 2,250km²

The areas close to the coastline can be calculated as the total coastline (7,300 km) multiplied by 500 m, which is equivalent to 3,650 km².

The total of the areas close to the surface waters can be calculated as approximately 9,900 km², which is equivalent to approximately 23 % of the total Danish area.

4.2 Geographical distribution of sites

The geographical distribution of contaminated sites (V2) and potentially contaminated sites (V1) in Denmark depends on where the activities leading to the contamination or potential contamination have taken place. Furthermore our present knowledge depends just as much on, where and how we trace these sites. In Denmark, the regional authorities started tracing contaminated sites in the beginning of the 1980'ies. Then, it was primarily waste dumps, gasworks and larger industrial sites that was mapped by the authorities. The mapping was thus carried out according the type of activity and not the geographical location of the site. In the 1990'ies, the mapping mostly included smaller companies. The authorities started to select and prioritize geographical areas inside which, the tracing was carried out. The selection of the geographical areas was primarily founded in a wish to protect the groundwater resource, and the last approximately 10 years, the authorities have thus primarily traced sites which are critical in relation to the groundwater resource, and where the substances used are assessed to constitute a hazard to the groundwater resource, se also section 3.3.3-3.3.4.

The geographical distribution of the sites which the authorities at present (2006), know about, are not representative in relation to an assessment of where the total number of sites are located. Areas which are critical in relation to the groundwater resource will be over-represented, while other areas e.g. coastal areas will be represented to a lesser degree.

Figure 4.1 shows the geographical distribution of mapped contaminated sites in 1997 (DMU 2006). It is assessed that the distribution of sites in 1997 gives a better estimate of the geographical distribution of the total number of sites, as the intensive tracing of sites in the groundwater sensitive areas only to a limited extent is included in the 1997 statement.

As shown in figure 4.1, the sites are evenly distributed across the country, with a tendency of the largest number of sites being in densely populated areas. This is both due to the fact these areas have most of the contaminating activities and also, that in these areas more building and construction activities are carried out, with a major probability of hitting the contamination. The assessment of the contaminated sites location in relation to surface waters is, however, independent of these circumstances.

Figure 4.1
Geographic distribution of sites in 1997 (DMU 2006)

In 1997, the regional authorities had mapped approximately 4,677 contaminated sites. In connection with reporting to the Danish EPA, the regional authorities have assessed that approximately 750 sites or approximately 16 % pose a potential contamination risk in relation to surface waters. The total number of contaminated sites located close to surface waters is probably higher, as sites located close to surface waters contaminated with immobile substances are not included in the 750 sites.

As stated in the previous section, it was assessed that areas close to surface waters constitutes approximately 23 % of the total area of Denmark. This should be compared to the assessment that approximately 16 % of the mapped sites pose a threat to surface waters, and that the number of contaminated sites close to surface waters is probably higher. On this basis, it is assessed to be acceptable to regard the contaminated sites as evenly distributed in relation to surface waters, and that approximately 23 % of the sites are located close to surface waters.

4.3 Number of major sites

Based on the annual reports to Danish EPA concerning major contaminated sites, the Danish EPA has summarized the following data: Approximately 87 larger contaminated sites have been reported of which 11 were major such as Høfde 42 and Kærgaard Plantage.

In 31 % of the cases, it has been stated that they might pose a risk to the surface waters. It is not known how far from the surface waters they are, but many of the major ones are very close to a recipient (e.g. Proms Kemiske Fabrikker, Stålvalseværket, Høfde 42, Kærgaard Plantage and Collstrup grunden).

The substances which in particular appear on the contaminated sites with potential risk to surface waters are (the number in brackets indicates the percentage of major sites with risk to surface waters, where the substance is present):

• Tar including PAH and phenols (35 %)
• Heavy metals (32 %)
• Oil (32 %)
• Chlorinated solvents (29 %)
• Cyanide (26 %)
• Petrol (16 %)
• The remaining approx. 10 %: chlorinated phenols, pesticides, barbiturates, phenyl acetic acid.

The above mentioned substances are typically part of the reason why remediation is carried out on major contaminated sites e.g. in consideration of the groundwater interests. Based on the reports, it can be established that, typically, remediation is not carried out on major contaminated sites in consideration of the surface waters.

Based on the percentage mentioned above, it can be calculated that:

• 8 major sites are contaminated with chlorinated solvents and are posing a risk to surface waters (87·31%·29% = 8).
   
• 3 major sites are contaminated with "other subtances" and pose a risk to surface waters (87·31%·10% = 3).

Of the 6 identified priority substances, it is assessed that there are less than 2 major sites contaminated with trichlorobenzene or trichloromethane and less than 2 sites contaminated with HCH (as lindane), nonylphenol, octylphenol and tributyltin compounds and posing a risk of exceeding the EQS in surface waters. Furthermore, in these cases the 6 identified priority substances are not expected to be the major contaminants and are therefore not defining the dimensions of the major remediation. Instead it is expected that contamination with any of the 6 identified priority substances to a large degree is remediated by the remediation methods used on the major contaminants.

4.4 Number of minor sites

In Chapter 3 (Section 3.5.2) seven (5 + 2) substances were singled out for further examination. Table 4.1 is a list of the typical types of contaminated sites for the seven substances. The list is based on the data in table 3.1 and 3.2.

Table 4.1:
Types of contaminated sites of relevance based on data in table 3.1 and 3.2 together with the following references:

1: Danish EPA (2006a);
2: Danish EPA (2006b);
3: Danish EPA (2006c),
4: AVJ (2002a),
5. US-EPA (2006)

In table 4.2 below, an estimate of the total number of potential sites in Denmark where use or production of the seven substances have taken place, is listed.

Table 4.2.
Estimate of number of potential sites where use or production of the 7 psingled out substances have taken place.

1: In AVJ (2000)
2: AVJ (2004a):
3: AVJ (2004b),
4: AVJ (1999),
5: Glensvig (2006),
6: DST (2006)
7: AVJ (2000),
8: Kjølholt (2006),
9: AVJ (2002a),
10: DS (1994):
11: US-EPA (2006);
12. Dahl Jepsen (2006)

The types of contaminated sites are discussed in the following. Waste dumps are addressed in section 4.4.7.

4.4.1 Sites contaminated with HCH/lindane

Of the mentioned types of point sources in table 4.2 it is assessed that production sites (NAB and possible Kemisk Værk Køge) are the major potential point sources for contamination with HCH. As the primary HCH used was lindane, the term lindane will be used in the following.

This is based on the fact that the amount of lindane handled and stored is large compared to the amount handled on agricultural farms. On the other hand, potential spills on farms might be high, though expected to be of a little size. AVJ (2002b) have compiled investigations on point sources of pesticides. The results regarding lindane are listed in table 4.3.

Table 4.3:
Results from investigations of point sources of pesticides (AVJ 2002b). Lindane was part of all analysis programmes in both soil and groundwater.

From the table it is seen that lindane is only found in groundwater on forestry sites. It is also interesting that lindane is not found in the groundwater, although it is found in the soil on 11-14 % of the horticulture and machine station sites.

Compared to the total number of investigated sites regarding groundwater (121), lindane was only found in the groundwater in 17 % out of 6 sites (1 site)

In total, the risk of groundwater pollution with lindane on agricultural sites can be estimated to:

• Groundwater: 1·100/125=0.8 %

Regarding the size of a spill, it is assessed that point sources on production sites might be more than 10·10 m and there might be several on every sites. Spills on agricultural sites are supposed to be around or smaller than 10·10m. As an average, it is assumed that the assumption on size of point source in the derived dilutions factors is acceptable.

Based on the data in table 4.2, a rough estimate on the number of relevant sites having used HCH/lindane is approximately 600 (74,000•0,8%).

In table 4.4, the dilutions factors estimated and the estimate on the need for dilution to comply with the EQSs are used to find the "safe" distance between a point source and surface waters. The safe distance is the distance, where EQS theoretically will not be exceeded.

Table 4.4.
Lindane. The shading indicates a risk of exceeding the EQS at the given distance in the given geological area. The area distribution given in per cent is the distribution of area either close to or far from surface waters divided into the different types of geology.

From table 4.4 it is assessed that point sources of lindane can constitute a risk of exceeding the EQS in surface waters, even from a distance in sandy geology and chalk, whereas it is assessed only to constitute a risk in till or clayey soils at a distance of less than 100 m from the surface waters.

Theoretically, at 45 % of all sites there is a risk that the EQS can be exceeded. Of these, it is assessed that in average 0.8 % of these have groundwater pollution.

Using these numbers, an estimate on the total number of sites having groundwater pollution and constituting a risk for exceeding EQS in surface waters can be calculated:

45%·600 sites=270 sites.

In addition to these smaller point sources, larger point sources from 1-2 production sites are expected.

4.4.2 Sites contaminated with nonylphenol/octylphenol

Of the mentioned types of point sources, it is assessed that the site types constituting the largest risk to surface waters are production sites for washing and cleaning agents. This is based on the assessment that the amount of alkylphenol ethoxylates used at primarily dry cleaners and washing shops and secondary paint productions is small compared to the amount handled at production sites for washing and cleaning agents. Neither in AVJ nor Danish EPA, an account of how often production sites of washing and cleaning agents, dry cleaners, washing shops or paint productions are polluted with nonylphenol or octylphenol are given.

Instead a conservative estimate of 1 % for all potential sites is given.

In table 4.5 and 4.6, the dilutions factors estimated (se table 3.9) and the estimate on the need for dilution to comply with the EQSs (se table 3.12) are used to find the "safe" distance between a point source and surface waters. The safe distance is the distance, where EQS will, theoretically, not be exceeded. For nonylphenol and octylphenol a total of 23 and 41% respectively of the area is characterized as at risk of exceeding the EQSs.

Using these data, a conservative estimate of the potential number of sites with point sources that are at risk of exceeding the EQSs for nonylphenol and octylphenol is:

Nonylphenol: ((85+300+60)·1%)·23% = 1 sites

Octylphenol: ((85+300+60)·1%)·41% = 2 sites

As an average it is assumed that the assumption on size of point source (10·10 m) in deriving dilutions factors is acceptable.

Table 4.5.
Nonylphenol. The shading indicates a risk of exceeding the EQS at the given distance in the given geological area. The area distribution given in per cent is the distribution of area either close or far from surface waters divided into the different types of geology.

Table 4.6.
Octylphenol. The shading indicates a risk of exceeding the EQS at the given distance in the given geological area. The area distribution given in per cent is the distribution of area either close or far from surface waters divided into the different types of geology.

4.4.3 Sites contaminated with tributyltin compounds

It is assessed that both winter storage places for yachts and ship building yards pose the major risk of exceeding the EQS in surface waters. This is based on the fact that the sites are all placed very close to coastal waters, lakes or larger rivers, and that the number of sites is large - 121, see table 4.2. Furthermore, the sites are generally characterized by having no pavement and only few drains and use of lot of water to clean the bottom of the boats. It is therefore assessed that the amount of infiltration of water contaminated with tributyltin compounds is potentially large.

It is expected that point sources of tributyltin compounds on winter storage places for yachts and ship building yards have a size exceeding 10·10 m, probably more e.g. few hundred meters times few hundred meter.

The dilution factors derived in section 3.4 is therefore probably too small for both ship building yards and winter places for yachts.

Paint production sites are also a potential point source, as tributyltin has been used in the production of ship paint. In Denmark, the number of paint production sites has varied between 50 and 85. Only very few of those have produced paints for ships. It is unknown, how many of these production sites that have used tributyltin and compounds, and there are no investigations on how often tributyltin is found on paint production sites. It is expected to be present on some disused production sites. A rough estimate on the number of paint production sites having used tributyltin compounds is 10-20 % of all paint productions sites, i.e. 10-15 sites.

The size of a point source contamination on a paint production site is expected to be approx. 10·10 m and several point sources can be present on every site.

As the need for dilution is a factor of several millions, it is assessed that tributyltin compounds constitute a risk of exceeding the EQS no matter the distance to the surface waters.

It is expected that the number of contaminated sites constituting a risk of exceeding the EQS is at least 121 winter storage places for yachts and 350 ship building yards described as large point sources and up to maybe 10 or 15 paint production sites.

4.4.4 Sites contaminated with trichlorobenzene

As it is seen from table 4.2, trichlorobenzene or TCB has been produced on 4 production sites in Denmark and has been used in dying, as a solvent in electronic production, as component in synthetic transformer oil, in lubricants and as heat-transforming medium.

On the 4 production sites, it is estimated that point sources are realistic and that the point source may have a size exceeding 10·10 m.

Regarding the use of trichlorobenzene in industries, it is unknown in how many places trichlorobenzene has been used. Based on expert knowledge, trichlorbenzene may have been used on approximately 1,000 industrial locations.

In COWI, expect knowledge of more than 30 years of work with all types of industries incl. electronic industries says that trichlorobenzene is seldomly investigated and never pointed out in analyses. Therefore, a conservative estimate of the risk of having a point source on a site is estimated to 5 %.

The average size of point sources of trichlorobenzene is expected to be around 10·10 m. It is therefore assumed that the assumption on size of point source in deriving dilution factors is acceptable, see section 3.4.

In table 4.7, the dilution factors estimated and the estimate on the need for dilution to comply with the EQSs are used to find the "safe" distance between a point source and surface waters. The safe distance is the distance, where EQS will, theoretically, not be exceeded.

Table 4.7.
Trichlorobenzene. The shading indicates a risk of exceeding the EQS at the given distance in the given geological area. The area distribution given in per cent is the distribution of area either close or far from surface waters divided into the different types of geology.

Theoretically, according to table 4.7, 45 % of all sites can constitute a risk of exceeding the EQS. Of these, it is assessed that, in average, no more than

5 % of these has a groundwater or a soil pollution.

Using these numbers an estimate on the total number of sites having groundwater pollution and constituting a risk of exceeding EQS in surface waters can be calculated:

45% · 1,000 sites · 5 %=23 sites.

4.4.5 Sites contaminated with pentachlorophenole

As it is seen from table 4.2, pentachlorophenole has primarily been used in leather and textile tanning and other facilities for preparation of leather and textile. Pentachlorophenole has also been used in wood preservation. Pentachlorophenole has not been produced in Denmark. From table 4.2, it is estimated that the number of sites having used pentachlorophenole is approximately 150.

Possible spills from tanning and wood preservation are assessed primarily to be outside while handling the chemicals or at stock. It has not been possible to find empirical assessments on the risk of soil and groundwater pollution from these type of locations. It is assessed that in less than 10 % of the sites has pentachlorophenol pollution with a size and a strength that can be called a point source constituting a risk to the environment.

As mentioned in chapter 3.5.1 pentachlorophenole has been singled out because EQS is smaller than WQS for this substance, where as EQS are lager than GQS. There fore it is assessed that point sources of trichloromethane can constitute a risk of exceeding the EQS only in "less valuable water abstraction areas"

Theoretically approximately 13 % of all sites will be located in "less valuable water abstraction areas", (e.g. figure 3.1) and therefore can constitute a risk of exceeding the EQS. Of these less than 10 % has a size and strength that can be called a point source constituting a risk to the environment.

Using these numbers an estimate on the total number of sites constituting a risk of exceeding EQS in surface waters can be calculated to less than 2.

13% · 150 sites · 10 %=2 sites.

4.4.6 Sites contaminated with trichloromethane

As it is seen from table 4.2, trichloromethane has primarily been distributed from companies selling laboratory and hospital articles, and used in laboratories (pharmacies, hospitals, R&D and testing). Trichloromethane has not been produced in Denmark. From table 4.2, it is estimated that the number of sites having used trichloromethane is several thousand (approx. 15,000).

Possible spills from laboratories and wholesale businesses are assessed primarily to be outside while handling the chemicals or at stock. It has not been possible to find empirical assessments on the risk of soil and groundwater pollution in laboratories and wholesale businesses. From more than 30 years of working experience in COWI, it is assessed that trichloromethane is found in less than 5 % of the investigations and that less than 1 % has a size and strength that can be called a point source constituting a risk to the environment.

As mentioned in chapter 3.5.1 trichloromethane has been singled out because EQS is smaller than WQS for this substance, where as EQS are lager than GQS. There fore it is assessed that point sources of trichloromethane can constitute a risk of exceeding the EQS only in "less valuable water abstraction areas"

Theoretically approximately 13 % of all sites will be located in "less valuable water abstraction areas", (e.g. figure 3.1) and therefore can constitute a risk of exceeding the EQS. Of these less than 1 % has a size and strength that can be called a point source constituting a risk to the environment.

Using these numbers an estimate on the total number of sites constituting a risk of exceeding EQS in surface waters can be calculated to less than 20.

13% · 15,000 sites · 1.0 %=20 sites.

4.4.7 Waste dumps

As mentioned in chapter 2, landfills are excluded in this report. Therefore, only waste dumps will be addressed.

Waste dumps are characterized by being large in total number, but generally relatively small in size. Typically, the filling height is less than 5 m and the total volume of the dump is less than 100,000 m³.

Generally, all the waste dumps have received waste uncontrolled and there is no environmental control measure or remediation regarding groundwater pollution.

The waste dumps have only seldomly received large amount of chemical waste, but typically only packaging from chemicals.

The waste is generally characterized by mixed waste, which from an environment point of view has the advantage that there is a high level of biologically degradation in the waste as well as in percolate downstream in the groundwater zone. This indicates that contaminants to a great extent are degraded in the plume.

It is therefore the experience that groundwater pollution from waste dumps only constitutes an environmental problem in the area close to the waste dump. Based on expert knowledge, an estimate of the safe distance regarding compliance with the EQS is approx. 500 m.

Using these estimates of safe distance and comparing them with estimates of dilution as a function of the distance to surface waters, it is assessed that the following substances may pose a risk of exceeding the EQSs in surface waters:

• HCH/Lindane (sandy and chalky sites)
• Tributyltin compounds (all geologies)
• Trichlorbenzene (sandy sites)

Experience from Danish research on groundwater contamination from landfills ("lossepladsprojektet") and international research at for example Waterloo in Canada has shown, that the biodegrading within the landfill body and downstream the landfill will minimize the amount of toxic substances leaking from the landfill. Therefore, it is roughly estimated that that pollution with the 3 mentioned substances will only be seen a few percentage of the landfills (1-5%) Of the 1,500 waste dumps known in Denmark, it is estimated that 30 % of these are located less than 500 m from surface waters.

The number of waste dumps constituting a risk of exceeding the EQSs in surface waters can therefore be calculated as:

1,500 · 30% · (1% to 5%) = 5 -25 sites.

4.5 Total estimate on sites of relevance

4.5.1 Sites at risk of exceeding the EQSs

In the following table, the estimated number of sites constituting a risk of exceeding the EQSs is listed.

Table 4.9:
Number of sites constituting a risk of exceeding the EQSs. See previous chapters for further information.

As it is seen from table 4.9, the number of sites of relevance is less than 350 smaller sites and less than 500 larger sites. For the small sites, HCH/lindane constitute more than 75% of the smaller sites, where as tributyltin constitute more than 98% of the lager sites.

4.5.2 Sites of relevance regarding phase-out of PHS

Losses of hazardous priority substances (PHS) to the environment are, according to the water framework Directive, eventually to be ceased. The number of sites of relevance regarding phase-out of hazardous priority substances can be found using the same method as used in section 4.5.1, just assuming that no dilution is accepted.

The number of relevant sites regarding phase-out of the hazardous priority substances HCH, nonylphenol and tributyltin compounds are listed in table 4.10 below.

Table 4.10:
Number of sites constituting a risk of activities regarding phase out of hazardous priority substances. See previous section for information.

As it is seen from table 4.10, the number of sites of relevance regarding phase-out of the hazardous priority substances is approx. 50 smaller sites and approx. 500 larger sites.

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Version 1.0 February 2009, © Danish Environmental Protection Agency