5.5 Environmental aspects
This is an enormous and complex subject, which can be summarised here in the form of a diagram:
Agrochemical companies are now obliged to allocate substantial resources to assess the environmental fate of compounds (and their metabolites). Even after registration, environmental concerns can be raised that may threaten the future of successful compounds (e.g. the neonicotinoids).
The fate of a given treatment in the environment is a function of its chemical properties, the way in which the pesticide has been dispersed and the properties of the soil, run-off, waterways, etc.
Screening of new compounds includes risk assessment of both ground and surface water contamination, involving extensive testing and computer modelling.
A number of standard tests take place on non-target organisms including birds (such as mallard ducks), fish (including rainbow trout), algae, water fleas (Daphnia spp.), bees and other beneficial species.
Inappropriate application can lead to off-target contamination due to spray drift, and “run-off” from plants causing contamination of the soil. Several studies have concluded that point source contamination (entry of pesticides to water courses/groundwater following spillage of concentrate or after washing equipment) often causes the greatest harm - especially to waterways.
During training sessions, time should be allocated to considering crop protection activities relative to the positions of water courses and wells.
For example, in order to protect water sources, it is especially important that farmers consider waste flows when washing out sprayers and the management of empty pesticide containers.
This is much more than empty containers being unsightly: malpractice potentially harms children, water sources, domestic animals, biodiversity, etc.
The disposal of empty pesticide containers remains problematic, but is now being addressed by the FAO/WHO/Global Environment Fund [1] and CropLife International [2] initiatives, including:
- (a) multi-trip, returnable containers and
- (b) one- way, single-trip containers made from recyclable materials.
Leaving packaging in the field or burning containers is not acceptable. This photo is especially problematical, since discarded containers indicate mixing took place near an important water source.
Containers should be rinsed three times, then operators should pour rinsate into the sprayer. If there is any risk of inappropriate re-use, containers must be punctured.
Cocoa growing communities are advised to develop appropriate and safe disposal methods. Ideally, this would best be organised in container return schemes with the involvement of pesticide suppliers.
