Environmental monitoring of pesticides
Environmental monitoring of pesticides at national level started in 2002, funded by the Swedish Environmental Protection Agency. The aim of environmental monitoring is to determine the extent to which different pesticides leak into surrounding waters and to monitor any long-term changes over time.
Monitoring is being carried out in four small catchment areas (800-1700 hectares), representing four large agricultural regions in Sweden. These areas are called type areas and are located in Skåne, Halland, Östergötland and Västergötland. In all areas, around 90% of the land area is used for agriculture. The water in the streams is sampled weekly from May until November and the samples are analysed for around 80 different substances. The farmers in the areas are interviewed about their cropping practices, while groundwater samples and sediment samples are also taken. Two rivers in Skåne and a site for collection of rainwater are also included in the environmental monitoring.
Results from environmental monitoring 2006
During 2006 there were fewer pesticide compounds that were above the guideline values in Swedish water samples compared with the previous year. In surface water, 14 substances were found at levels above their guideline value at some time during 2006. Most findings above the guideline value were of metazachlor. 2006 was the first year in which neither terbutylazine nor its breakdown product DETA was detected at concentrations above the respective guideline value. This indicates that the concentrations are now declining after the ban on this substance in 2003.
However the measurements in rainwater in Skåne show an increased incidence of pesticides in the samples taken during 2006. Researchers found a maximum of 31 different substances. Herbicides were the most frequent and were found in all rainwater samples. Around one-third of the compounds are no longer used in Sweden. These have been transported here with the wind from other countries.
In sediment samples taken from streams and rivers in September, traces were found of seven pesticides and three breakdown products. Most finds were made in the River Vege, where seven of the substances were detected. Glyphosate was found at five of the sampling locations and was thus the most common substance in the sediment. Glyphosate is the pesticide used most commonly in Sweden, e.g. to break fallow in summer.