Extent of sampling
Sampling of surface water in the model catchments is automated, by ISCO-samplers that are programmed to take a subsample every 80 minutes. Subsamples are combined into weekly samples that show which pesticides have passed through the sampling station and what their average concentration was during the week. These samples are collected from May to October, the period of highest pesticide application rates in Swedish agriculture. For the model catchments in Skåne and Halland the sampling continues throughout the year, but with less frequent subsampling and bimonthly composite samples. These samples are collected to examine if remnants of pesticides are leached from arable land during the winter months.
Surface water samples from the larger streams/rivers are collected as grab samples by submerging bottles into the stream once or twice per month between May and October.
Groundwatersamples are collected four times per year and sediments once a year.
Precipitation samples are collected regularly after precipitation events between April and October in Vavihill/Hallahus (Söderåsen) and May to September in Norunda (previously in Aspvreten). In total 10-15 precipitation samples are collected for each location and year. Around 10 air samples are collected annually at Vavihill/Hallahus by sampling devices that actively suck in air through a filter containing an adsorbent (PUF), which is then analyzed for pesticides.