Tuesday May 20 the Symposium ‘Natural Vinegar: (im)possibilities for weed control’ took place. Four speakers highlighted the following topics: implications of pesticide use for the drinking water sector (Rosa Sjerps, MSc, KWR), the possibilities for the use of Natural Vinegar for weed control (Kelsey Walker, MSc, UvA), developments in weed control in urban areas (ir. Joop Spijker, Alterra) and the current knowledge of the use of acetic acid in weed control (prof. dr. Michel Haring, UvA).
Vinegar (‘Natuurazijn’) is a food product that contains acetic acid (10-20%) and traces of proteins, alcohol, nutrients and minerals. The quantity of acetic acid present in vinegar determines the specific use and the environmental effects.
The following legal frameworks are important concerning the use of acedic acid for the appliance of weed control:
- Currently the professional use of chemical plant protection products on paved and unpaved surfaces is prohibited in The Netherlands, potentially this will also apply in the future for recreational terrains.
- Private use of chemical pesticides is allowed.
- The Ctgb authorization institute for pesticides has an admittance for acetic acid as active ingredient in weed control products for non-professional use.
- However, the RIVM discourages the use of these products because the effect of these substances on the environment has not yet been assessed.
- The product ‘Natural Vinegar’ produced by the Burg Groep has not yet been authorized by the Ctgb.
Michel Haring, professor plant physiology of the UvA studied the effectiveness and the risks of the product Natural Vinegar’. The active ingredient acetic acid is effective for weed control, however less for grasses, and the application has to be repeated in four weeks’ time. The effective concentration of acetic acid is between 10-30%. Acetic acid is degradable in soil and water and feeds algae and bacteria. Potential identified risks for ecosystems are the oxygen depletion in soil and lowering of soil acidity, however, science-based knowledge is lacking. Because of the high degradability and low health effect levels, human health risks by drinking water consumption are not expected. Potential human health risks are identified by inhalation and skin contact during application.
The producer of Natural Vinegar, the Burg Groep, is currently working on the authorization of the product and performs more research for the effects on soil and aquatic ecosystems.