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close this bookEnvironmental Handbook Volume II: Agriculture, Mining/Energy, Trade/Industry (GTZ, 1995, 736 p.)
close this folderAgriculture
close this folder28. Plant protection
View the document1. Scope
View the document2. Environmental impacts and protective measures
View the document3. Notes on the analysis and evaluation of environmental impacts
View the document4. Interaction with other sectors
View the document5. Summary assessment of environmental relevance
View the document6. References

3. Notes on the analysis and evaluation of environmental impacts

Plant protection measures have a wide variety of impacts on the environment. As there are no universally applicable concepts, methods must be assessed by comparing their environmental impacts. In order to weigh up alternative plant protection methods, assessment criteria are needed. This calls for indicators which convey qualitative and quantitative impacts - including their duration - as accurately as possible so as to permit comparison (cf. environmental brief Plant Production). The active ingredients, additives and conversion products of pesticides are analysed to establish their physical and chemical characteristics (persistence, evaporability, adsorption, desorption etc.). Reproducible measured values incorporating safety factors are used to determine their toxicity and residue properties (acute 50-values), chronic toxicity (no-effect level, acceptable daily intake [ADI]), maximum-quantity regulation (permissible level). The values serve as indicators or limits and must be compared with the actual contamination levels in foods and animal fodder, flora and fauna, soil, water and air. Synergistic and additive effects resulting from use of pesticides can be identified only by studying the relationships between environmental impacts (e.g. decline in particularly sensitive species, use of indicator plants, diversity studies etc.). These relationships are as yet known only in part and are to some extent obscured by the effects of other measures; in many cases they thus cannot be ascribed to plant protection measures alone.

Findings which have emerged during implementation of plant protection measures (e.g. depletion of resources or adverse social consequences resulting from such measures) provide pointers for additional assessment criteria.

Where negative environmental impacts are likely, it must be considered whether these can be remedied without excessive outlay. Risks of irreversible damage must be ascertained separately and assessed accordingly. Plant protection methods have an influence on employment structures (e.g. division of labour between men and women, workload and capital requirements). Further assessment criteria can be developed on the basis of their impacts on farm structures and production.