1. What are pesticide metabolites?
Metabolites are chemical molecules produced by the breakdown of pesticides used in agriculture or by private individuals.
A distinction is made between "relevant" and "irrelevant" metabolites, depending on their properties. A "relevant" metabolite is a molecule which, because of its toxic activity or properties, is considered in the same way as a conventional pesticide. An "irrelevant" metabolite is one whose activity is altered in such a way that it is not toxic. Irrelevant metabolites do not retain the same activity as their parent substance or pose a health risk to consumers.
Metabolites are chemical molecules produced by the breakdown of pesticides used in agriculture or by private individuals.
A distinction is made between "relevant" and "irrelevant" metabolites, depending on their properties. A "relevant" metabolite is a molecule which, because of its toxic activity or properties, is considered in the same way as a conventional pesticide. An "irrelevant" metabolite is one whose activity is altered in such a way that it is not toxic. Irrelevant metabolites do not retain the same activity as their parent substance or pose a health risk to consumers.
2. What products contain pesticide metabolites?
Metabolites do not exist in their natural state, just like the pesticides from which they are derived. These come from the petrochemical industry and are used both in agriculture and by private individuals.
3. Are metabolites dangerous to health?
Certain metabolites can be recognised as toxic. They are then treated as relevant metabolites and therefore subject to standards.
There is very little toxicity data on irrelevant metabolites. They are monitored as a preventive measure.
4. Why are metabolites found in the environment?
Once pesticides are released into the environment, they break down. A part of them is converted into metabolites. Most of these are mobile and persistent and can therefore be found in different water matrices, such as surface water or groundwater.
For further information, contact http://etat.environnement.wallonie.be/contents/indicatorsheets/EAU%2014.html
The Walloon Government Decree of 1 June 2023 sets out the following standards:
Pesticides, relevant metabolites
| 0.10 | µg/l | Pesticides are defined as:
A pesticide metabolite is considered relevant for water intended for human consumption if there is reason to believe that it has intrinsic properties comparable to those of the parent substance in terms of its pesticide target activity or that it poses a health risk to consumers.
|
Aldrin, dieldrin, Heptachlor, Heptachlorepoxide
| 0.030 | µg/l |
|
Irrelevant metabolites
| 4.5 | µg/l | An indicative value of 4.5 μg/l is defined for the purposes of managing the presence of irrelevant pesticide metabolites in drinking water. The Minister may set a lower limit for irrelevant metabolites that show signs of toxicity.
|
6. Does tap water contain irrelevant metabolites?
The comprehensive controls planned for 2024 will provide an answer to the question of the presence of irrelevant metabolites in tap water. The results will gradually be made available to SWDE customers through the water quality sheet available on the website and with their annual bill. This will supplement the information already available on all pesticides.
7. How are pesticide metabolites detected in drinking water?
Metabolites are analysed using high-performance laboratory equipment. The technology used is high-performance liquid chromatography (HPLC) coupled with mass spectrometry (MS-MS). This technique enables metabolites to be separated, identified and quantified.
8. What solutions are deployed in the event of the presence of metabolites?
Solutions need to be analysed on a case-by-case basis. On the one hand, two water resources can be mixed to reduce the pesticide (metabolite) content in the drinking water. There are also water treatment solutions, such as activated carbon filtration.
Activated carbon has a high adsorbent capacity, meaning that it retains on its surface certain molecules (including pesticide metabolites) that come into contact with it.
The effectiveness of the activated carbon treatment is monitored and evaluated over time. Activated carbon is regenerated as soon as its adsorption capacity begins to decrease.
9. What information is provided if the standard for pesticide metabolites is exceeded?
If the standard for pesticide metabolites is exceeded, this is treated in the same way as any other event affecting drinking water quality.
The Walloon Region does not issue health recommendations.
10. What are the regulations for other foods?
For more information on EU and federal legislation concerning the control of pesticide residues in foodstuffs, click on the following link to the FASFC website