Summary and conclusions

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

A proposal for an EC Directive on Priority Substances under the Water Framework Directive was put forward by the European Commission in July 2006. An initial assessment has been carried out on whether one or more of the priority substances (PS) can be expected to constitute a risk of exceeding the Environmental Quality Standards (EQSs) in surface waters due to losses from contaminated sites and soils.

Furthermore, an assessment has been carried out on which of the priority hazardous substances (PHS), in relation to soil and groundwater contamination, need to be handled if it should be decided to stop losses of PHSs to the aquatic environment completely.

In the final version of the Daughter Directive proposal (COM(2006)397 final), EQSs are also established for a group of eight substances called "other pollutants" (Annex I, Part B). These substances have been included in the initial assessment.

In continuation of these, an estimate on types and number of sites of relevance was given.

The assessment on relevant priority substances is based on a screening of the following:

Use and production - both present and historical
Physical-chemical properties
Toxicity
Common practice including quality standards such as Groundwater Quality Standards (GQS), to answer the question: Will the contaminations be detected in the framework of common practice and legislation

The following substances were screened out as their use volume was less than 1 ton/year: Hexachlorobenzene, hexachlorobutadiene, pentachlorobenzene, isodrin, aldrin, C_10-13-chloroalkanes, chlorfenvinphos, chlorpyrifos, 1,2-dichloroethane, dieldrin and endrin.

As endosulfan has only been used in very small amounts (2 tons/year), presumably on very few locations, and has only been produced on one site in Denmark, endosulfan was screened out too. The Priority Hazardous Substances anthracene, pentabromodiphenylether, cadmium and compounds, mercury and compounds pentachlorobenzene and PAH were screened out based on their physical and chemical properties, i.e. low mobility in the soil and groundwater zone. This means that 10 out of 13 of the PHSs were screened out.

Based on the screening, it was assessed that the following 6 priority substances, in case of a soil and groundwater pollution, posed a potential risk of exceeding the EQS in surface waters:

HCH/lindane
Nonylphenol
Octylphenol
Tributyltin and compounds
Trichlorobenzene
Trichloromethane

Of these the following 3 are classified as PHSs:

HCH/lindane
Nonylphenol
Tributyltin compounds.

For each of the 6 substances a necessary dilution factor has been established, in order to comply with the EQSs for surface waters. The dilution factor is established as the relation between an estimated source concentration and EQS. The critical areas have been identified from the dilution factor and the estimated mixture and dilution in the groundwater and surface waters. The number of possible sites which are assessed to pose a risk for unacceptable contamination of surface waters, have been estimated by comparing the critical areas with an estimate of the number and location of area, which might be contaminated with the actual substance.

Major polluted sites in Denmark and waste dumps were included in the estimate.

It was seen that for each of the 6 priority substances except tributyltin compounds, less than 350 smaller sites and a few larger sites were expected. For tributyltin, the number was around 500 larger sites, primarily winter store places for yachts and shipbuilding yards.

Regarding the number of sites contaminated with the PHSs HCH/lindane, nonylphenol and tributyltin compounds, it was estimated that a total of approx. 630 smaller sites and 500 larger sites might need to be remediated in order to stop losses of the PHSs to the environment. As this assessment is based on generalized assumptions and done within a statistical framework, specific investigations or monitoring of surface waters would be necessary in order to evaluate the actual risks posed by these sites.

This document is based on the assumption that losses of the PHS's ought to be stopped. In reality this implies that measures should be taken by Denmark with the purpose of stopping the losses. By aiming to stop the losses through the necessary measures Denmark will fullfill its obligation as stated in the Water Framework Directive.