One Health - Azole fungicides in Europe’s rivers, lakes and groundwater

Key points from One Health study into uses of azoles other than as human medicines

Between 2010 and 2021, approximately 120,000 tonnes of azoles were sold in the EU/EEA(European Economic Area) for non-medical purposes. Over 119,000 tonnes of these azoles were used for plant protection, with a stable annual average of 10,000 tonnes.

Substantial evidence supports a link between environmental azole fungicide exposure, azole resistance selection in Aspergillus spp. and cross-resistance to medical azoles.

 Non-medical use of azoles likely contributes to the environmental selection of azole-resistant A.fumigatus, potentially leading to infections caused by azole-resistant A. fumigatus. Further research is required to estimate the extent of this contribution.

More information in the plain language summary of the joint report of the agencies 2025 and full report here.
Annex A contains a detailed assessment of uses of azoles.

Azole resistance in Aspergillus spp.

Azole substances are used against fungi (moulds). Aspergillus species (spp.) are fungi commonly found in the environment. They can cause severe respiratory diseases in humans, like invasive aspergillosis, chronic pulmonary aspergillosis and allergic bronchopulmonary aspergillosis.  Aspergillosis is primarily treated with azole medications, with few effective alternatives available. Aspergillus spp. can develop resistance to azole fungicides, reducing the effectiveness of azole medications. This resistance may result from prolonged medical treatment or environmental exposure to azoles.

Thresholds used to assess exceedances

Effect thresholds for surface water and quality thresholds for groundwater in water assessment refer to concentration limits of pollutants above which harmful effects on organisms or ecosystems are likely to occur. If a measured concentration in water is above the threshold, it is considered an exceedance, indicating potential ecological or health risks. To assess pesticide exceedances, effect thresholds were assigned to each azole. In surface waters, the threshold from the 2020 Watch List maximum detection limit was used, which is based on the predicted no effect concentration (PNEC). In groundwater, the 0.1 µg/L standard for pesticides set in the Groundwater Directive was used. See the full list of azoles' thresholds used for surface water assessment in Table 1 under "Methodology".

The maps show the data for Eionet countries that have reported azoles data relevant for the assessment to the EEA for the period 2020 to 2023.

European countries can report chemicals concentration data in surface and groundwaters to the WISE-6 water quality dataflow hosted by the EEA. The WISE-water quality database is updated annually, it holds water quality data from across Europe for over 900 substances, with some records (mainly for nutrients and metals) going back to the late 1980s.

The surface water watch list was established under the Environmenta l Quality Standards Directive to gather data on newly emerging pollutants, to enable assessment as to whether they represented an EU-wide risk. In 2020, the Watch List included 10 azoles (clotrimazole, fluconazole, imazalil, ipconazole, metconazole, miconazole, penconazole, prochloraz, tebuconazole and tetraconazole).

The methodology for exceedance detection has been adopted from that used in the EEA indicator for pesticides in rivers, lakes and groundwater  

A detailed description is provided in "Methodology for indicator on pesticides in European waters, ETC BE".