Analyse relevant compounds
Many different compounds have been used as pesticides over the years, some that have been banned and others that have replaced them. They have been used for different purposes and in different ways. The compounds that are relevant to analyse in a sample depend for example on whether the surface water or groundwater is being investigated. Any residue of pesticides present in surface water are often a reflection of what is in current use, while those found in groundwater are more a reflection of what has been used in the past, sometimes several decades in the past, within different sectors of society. An indication of the types of compounds that are relevant for analysis can be gained by looking more closely at the type of use that has existed and still exists in the immediate area – whether it is agricultural use, urban use or forestry use that dominates. It is often difficult to predict which substances will appear since there is, and always has been, a great variation in how the products are used, especially before the current stricter regulations for use and handling were introduced in the 1990s.
There are several different places to look for information on the compounds that are relevant in different questions.
The Swedish Chemicals Agency publishes annual reports with statistics on quantities of different compounds sold (1986 onwards). Their website also has a search function where information can be sought on areas of application or on a certain compound. The Chemicals Agency has also compiled a list of soluble compounds in permits issued for water protection areas (in Swedish only) which can be interesting to include in the analyses.
SLU has an internet service 'Pesticides in the environment' (in Swedish only) containing the results of analyses collected from different parts of Sweden. The user can decide whether to look at surface water, groundwater or drinking water, and information is given on e.g. the compounds found most frequently, both in the entire country and at county level. The user can also look at the compounds found in the environmental monitoring being carried out in four intensive farming areas of Sweden. Please contact SLU for information in English on this matter.
If the water to be sampled is affected by farming, it is best to get in touch with an experienced agricultural advisor in the region, as they usually have good knowledge on the compounds used in the area. This depends partly on the crops grown and partly on the insects and fungi that occur.