Summary and conclusions

Udvikling i pesticiders belastning af miljøet i perioden 1986 til 2006

The impact of pesticides on the environment was assessed by calculating load indices for aquatic and terrestrial organisms, for their mobility in soil and for their endocrine disrupting and carcinogenic properties.

Furthermore, estimates were made to illustrate the influence of the introduction of protection zones for water environments towards substances of very high concern.

It is important to stress that load indices cannot describe effects but only illustrate the load on the environment as a result of application of substances with specific properties.

Since 2000-2002, the load index does not show any major development in general, neither increase nor decrease, which indicates an unchanged environmental impact in this latest period. Before that, distinct improvements had been seen for many years. Generally, the load indices for the 80s and first half of the 90s were thus at a much higher level than those for the second half of the 90s and up to 2006. Similar trends are seen for the application of pesticides with endocrine disrupting properties, carcinogenic properties and properties with high risk of leaching to the ground water. An exception is the load index for earthworms, which has increased throughout the entire period from 1992 to 2006. Other exceptions are the load index for algae, which has increased during recent years, and those of birds and mammals, which show a slight tendency to decrease lately

During the 90s, a general fall is seen in both the application frequency and in the majority of the load indices.

The trend of the load indices does not clearly reflect the increase in the frequency of application in the period after 2000. This may be due to the fact that, at the calculation of the load frequency, the toxicity of the pesticides is not taken into account, only their dosage and consumption. This means that there is not necessarily any evident and unambiguous relation between frequency of application and load index.

There was, however, a relation between the use of certain pesticides and the load index, and a number of substances could be identified, which were decisive for the trend of the different load indices. More stringent requirements to the authorisation of pesticides thus have an effect on the environmental impact.

In relation to watercourses and lakes, spray-free protection zones are an important means, which was included in the estimations. The conclusion is that all of the substances most affecting the load index of the water environment were subject to protection zones until the year 2000. The following years, no further marked reduction occurred for the load indices of substances that may be sprayed without any protection zone. Of course, only surface waters benefit from protection zones for the aquatic environment, and therefore, they are only relevant to the three groups of aquatic organisms included (algae, crustaceans and fish).

In future, with suitable maintenance - and potential improvements - the load index may be used as a supplement to the frequency of application for monitoring the development in the load of pesticides on the environment and for identifying the substances that influence the individual load indices the most.