Pesticides threatening European rivers - time to update the risk list?
In a new EU-funded study, a pan-European team of scientists has flagged up a number of nasty pesticides that pose a threat to river ecosystems and which they believe should be added to the list of chemicals classified as risky in the EU Water Framework Directive.
Writing in the journal Science of the Total Environment, the team from Belgium, Germany, Spain, France and Slovakia present their findings based on an analysis of 500 organic substances in the basins of four major European rivers. They found that contamination by organic chemicals is a problem throughout Europe. They discovered that 38% of these chemicals are present in concentrations that could prove to be devastating for the organisms that call the river basins home.
The work was supported by the European Commission through EUR 8.4 million of funding from the MODELKEY ('Models for Assessing and Forecasting the Impact of Environmental Key Pollutants on Marine and Freshwater Ecosystems and Biodiversity') project and EUR 10 million of funding from the OSIRIS ('Optimized strategies for Risk assessment of chemicals based on Intelligent testing') project, both part of the 'Sustainable development, global change and ecosystems' Thematic area of the EU's Sixth Framework Programme (FP6).
As part of the MODELKEY project a database was developed that contains five million records on physicochemical data. The study focused on organic pollutants recorded in over 750,000 entries of water analyses in the basins of the Elbe (Czech Republic/Germany), the Danube (which runs through 10 neighbouring European countries), the Schelde (Belgium) and the Llobregat (Spain) rivers. This is the first study to have developed such a system that classifies organic pollutants on the basis of assessment criteria and the need for action.
The aim of the EU Water Framework Directive is that surface water and groundwater bodies should reach a good environmental and chemical status by 2015. This chemical status will be assessed based on a list of 33 so-called priority pollutants. But with over 14 million chemicals on the market and over 100,000 of these being produced on an industrial scale, monitoring them has to be confined to a manageable scale and it is scientists who are working hard to establish which pollutants pose the greatest danger.
This type of research is therefore vital for keeping the Directive up to date. Today the majority of the substances currently presenting problems are not listed, while many of the chemicals still being monitored have actually been banned for some time and are no longer used.
In their study the scientists classified a total of 73 compounds as potential priority pollutants and around two thirds of these were pesticides. Pesticides are products used in agriculture to protect crops against disease, pests and weeds. The most problematic pesticides were diazinon, which is already no longer allowed in Austria and Germany, as well as azoxystrobin and terbuthylazine, which are still allowed in Central Europe.
'Neither of these pesticides is on the list of 33 priority pollutants, which have to be monitored by authorities throughout the EU,' explains lead author of the paper Dr Peter Carsten von der Ohe from Helmholtz Centre For Environmental Research - UFZ in Germany. 'Terbuthylazine is a compound that is structurally closely related to the priority pollutants simazine and atrazine, which may not be applied any more. This is a nice example how small structural modifications of chemical products may apparently improve the chemical status without mitigating any hazards to the aquatic ecosystems.'
One of the most frequently registered compounds was diethylhexyl phthalate (DEHP), a chemically-produced softener which may impair fertility and will be banned in the EU as of 2015. Another softener that also frequently showed up in the database was bisphenol A (BPA) which has been shown to impair fertility.
The team also underline that despite these shortcomings their findings do in fact show how successful the EU Water Framework Directive has been, as one third of the pollutants classified as priority a few years ago by the EU now no longer present a risk to the rivers studied. So while their study shows the list needs to be regularly updated, the fact that some pesticides can now be 'struck-off' the risk list shows we are moving in the right direction.
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Category: Project results
Data Source Provider: Helmholtz Centre For Environmental Research - UFZ
Document Reference: Carsten von der Ohe, P., et al. (2011) A new risk assessment approach for the prioritization of 500 classical and emerging organic microcontaminants as potential river basin specific pollutants under the European Water Framework Directive.
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