5 Assessing the need for further action

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

5.1 General problem or not?

As it is seen from the previous chapters, 6 of the 41 substance studied (33 priority substances (PS) + 8 other pollutants (OP))are assessed to pose a risk of exceeding the EQSs in surface waters due to point sources in soil and groundwater: HCH/lindane, nonylphenol, octylphenol, tributyltin compounds, trichlorobenzene and trichloromethane.

Of these, 3 priority substances are classified as priority hazardous substances (PHS): HCH/lindane, nonylphenol and tributyltin compounds that ought to be phased-out.

It is also seen that the total number of relevant sites posing a risk of exceeding the EQSs are estimated to less than 850 sites in total for all 6 substances. For nonylphenol and octylpheno the number of sites is estimated to only one or two smaller sites and no larger sites. Therefore, the focus should be on sites polluted with trichlorobenzene and trichloromethane (approximately a dozen sites for each substances), HCH/lindane (app. 270 smaller sites and a few lager sites) and to tributyltin compounds (less than 500 larger sites).

The number of sites contaminated with the 3 priority hazardous substances HCH/lindane, nonylphenol and tributyltin compounds is estimated to a total of approx. 650 smaller sites where HCH/lindane constitute the majority of the sites, and les than 500 larger sites where tributyltin compounds constitute the majority of the sites (the number of sites is larger in this situation because the acceptance criterion is more stringent (i.e. "zero")).

Need for further knowledge

As it is seen from section 4.4, for several of the identified substances no accessible information on how often they are found as point sources and even less information on how often they are considered a risk towards surface waters have been available. This means that the estimates in section 4.4 on number of sites constituting a risk of exceeding EQSs are very uncertain. This uncertainty can be overcome by making investigation on 5-10 relevant sites for each substance or making a more intensive compilation of previous investigations.

Despite this uncertainty, it is assessed that for the 6 substances of concern, the number of sites of concern are probably in the right magnitude, though it is stressed that this study is only introductory.

There is one major problem regarding the number of relevant sites: In practice it will be difficult to identify the relevant sites, i.e. those that pose a risk to the environment, as the percentage of the total number of sites actually being contaminated and posing a risk is very little. This means that the effort regarding investigations, analysis and assessments to locate these few sites can be very large.

5.1 General problem or not?

It is assessed that the possible expenses to investigate and possibly remediate sites polluted with tributyltin compounds may be extraordinarily high compared to the other identified substances due to the fact that the contaminations need to be cleaned up, or contained thoroughly to ensure compliance with the EQSs, as the need for dilution is several million times.

Excluding tributyltin and its compounds, and only looking at the other substances and identified sites of concern, it can be discussed whether a few point source sites qualify a problem to be considered a general problem. For many of the sites, other types of contaminations are to be dealt with, and it is the experience in COWI that many of these types of contaminations are indirectly dealt with when major remediation actions are implemented.

It is therefore assessed that especially - if not only - tributyltin compounds among the priority substances may constitute an environmental issue of general character in relation to the Daughter Directive.