This study assesses whether groundwater within the European Union (EU) faces a similar potential for widespread contamination by MTBE as has already occurred in the USA, and whether this risk is mitigated by controls or obligations present in Member States that may or may not exist in the USA. Three factors were considered as part of this assessment:
1. UST Construction, installation and operation. What are the key differences between requirements for UST systems in the USA and those in the Member States?
2. Regulation of Water Quality. How does the United States Safe Drinking Water Act (SDWA) and associated water quality legislation compare to the equivalent EU Groundwater (80/68/EEC) and Drinking Water (98/83/EC) Directives?
3. MTBE monitoring programmes. Does information from EU groundwater monitoring programmes suggest widespread groundwater contamination by MTBE is already occurring throughout Member States?
Legislative information was collated from the USA and compared with data gathered from government ministries and environment agencies within the EU. Analysis of these data suggested that: Widespread MTBE contamination on the same scale as in the USA (especially California) is unlikely. The risk of groundwater contamination is unlikely to increase, given important differences between the USA and the EU, although robust enforcement of the existing Member State regulatory framework is required to ensure this risk remains low in the future.
Three findings supported this conclusion:
1. Standards of UST construction and operation. Our survey revealed that Member State requirements for the construction and operation of UST systems generally met or exceeded the new United States requirements revised under Subtitle I of the Resource Conservation and Recovery Act (RCRA), although it should be noted that many of these requirements have only been adopted or revised
2. Water Quality Legislation. Many of the regulatory controls mandated in the US under the SDWA and RCRA can also be found in the equivalent European Directives. The new ‘combined approach’ used under the Water Framework Directive now integrates a number of Directives regulating water quality that were established during earlier tranches of environmental legislation.
3. Monitoring of Groundwater Contamination. Although there is little publicly available information within the EU on groundwater contamination by MTBE, none of the existing reports suggest widespread or serious groundwater contamination by this gasoline component. It is likely that monitoring of groundwater contamination by MTBE will increase as the river basin management systems are established by Member States, especially where responsibility for water quality within a given river basin is shared by more than one Member State. Identifying the sources of pollution will facilitate the use of economic instruments by Member States to recover the cost of water services, an approach that forms part of the polluter-pays principle integrated under the Framework.
Adequate enforcement of Member State requirements for the construction and operation of UST systems is the key to safeguarding water quality in the EU.
Three additional findings were considered of relevance to this study:
1. Pattern of MTBE consumption. The 2 percent minimum oxygen content mandated under the United States Clean Air Act represents a significant driver for increased usage of MTBE in gasoline. Changes in fuel specification in the EU adopted out of the Auto Oil II programme are not anticipated to generate equivalent demand for fuel oxygenates.
2. Geology. California represents a ‘special case’ where a technologically advanced economy with a high per-capita water consumption is reliant on shallow aquifers to abstract water from a depressed water table. It is difficult to find an equivalent set of circumstances within the EU, given that arid regions such as the interior of Spain and Greece support lower populations than California.
3. United States economy. The USA has traditionally enjoyed at-the-pump gasoline costs of up to one quarter of those found in EU Member States. These low costs encourage high levels of car ownership and use in the United States, where the fuel of choice for private users is unleaded gasoline.
This contrasts with the situation in Member States, where the high cost of fuel makes diesel a popular second choice after unleaded gasoline for private motor vehicles on grounds of fuel efficiency. This reduces the quantity of MTBE-containing fuel sold across Europe by virtue of the fact that diesel does not contain MTBE within the last five years.