Residues in UK water among the highest in Europe

A new survey of sources of drinking water shows that the UK has some of the highest levels, according to EUREAU, an organisation that represents water industry associations across Europe. 

Since just 100 grammes of some pesticides can contaminate up to one billion litres of water, pesticide removal is an expensive process. Over the last ten years the UK water industry has spent £1 billion in capital expenditure and £100 million per year in running costs to eliminate pesticides from water sources. This is not sustainable over the long-term as pesticide removal is an energy and resource intensive process. To protect human health, the EU has set a limit of 0.1µg/l (parts per billion) as the allowable residue of any single pesticide in drinking water. 
    The EUREAU report confirms that pesticide contamination is particularly acute in the UK, Belgium, France and the Netherlands. In all these countries a high proportion of the raw drinking water resources are contaminated with pesticide residue levels that regularly exceed the drinking water limit of 0.1 µg/l (parts per billion), often by a significant margin. In the most affected countries of Belgium, Denmark, France, Germany, Netherlands and UK between 5-10% of resources regularly contain pesticides in excess of 0.1 µg/l. 
    For the UK, the report cites a survey covering a water supply population of nearly 16 million people where 77% of raw surface water (from rivers and lakes) is contaminated with pesticides above the 0.1 µg/l limit. In some areas there is growing concern about the threat to future contamination of groundwater sources, as pesticide residues from historic use and current use pass through overlaying rocks to the aquifer.
    The report cites a ranking system, those substances which most regularly cause problems. For groundwater the chemicals are - atrazine (and related products), bentazone, mecoprop, simazine; and for rivers - atrazine (and related products), chlortoluron, diuron, glyphosate (AMPA), isoproturon, MCPA and mecoprop. 
    Water UK, the national member organisation, is working with EUREAU on measures to tackle pesticide contamination of raw water. These include: 

• an assessment of the need to ban or severely restrict use of certain pesticides 
• use of regulatory instruments and positive financial incentives to promote good practice; 
• promotion of 'best practice' within farming and weed control on roads and runways;
• better use of measuring data and more targeted action to deal with pesticide hotspots; 
• a multi-stakeholder taskforce to develop a European strategy for combating pesticide pollution, to include the water industry, farmers, pesticide manufacturers and distributors, food retailers, consumer groups, green groups, the European Commission and regulators. 

Keeping raw drinking water resources safe from pesticides, EUREAU Position Paper, EU1-01-A56, 2001, www.water.org.uk 

[This article first appeared in Pesticides News No. 53, September 2001, page 11]