Clotrimazole is a pharmaceutical. It's mainly used to treat dermatological and gynaecological fungal infections.
Approximately 10 tonnes are produced in the EU each year, and almost the same quantity is imported. The main potential source of clotrimazole to the environment is discharges from municipal waste water treatment plants as a result of waste water from households.
Clotrimazole is a toxic substance for aquatic organisms. Concentrations of only 20 µg/l cause lethal effects on crustaceans. Fish can tolerate short exposures to concentrations bellow 0,29 mg/l although they might be affected by prolonged exposure to clotrimazole concentrations of 0,025 mg/l. In rats, doses of 50 mg per kg body weight caused a reduced survival rate of pups. Microalgal communities might be extremely sensitive to the substance. Concentrations of 17 ng/l might already have adverse effects on algae and concentrations of 3,5 µg/l cause visual effects on community growth.
The highest concentration measured in estuaries is 22 ng/l, the median is 7ng/l.
In 2005 OSPAR considered it unnecessary to propose measures for the reduction of discharges of clotrimazole.
Environmental standards and legislation
- OSPAR Commission, 2005: OSPAR background document on clotrimazole
- Porsbring Tobias; Blanck Hans; Tjellström Henrik; Backhaus Thomas 2009, Toxicity of the pharmaceutical clotrimazole to marine microalgal communities. Aquatic toxicology (Amsterdam, Netherlands) 2009;91(3):203-11.
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