The water quality standards (wqs) indicate the maximum level at which no negative effects of a substance can be expected.
In 2004 the Swedish Chemicals Agency (KemI) devised wqs for 100 active substances in authorised plant protection products and in some cases also for the breakdown products of these substances. In 2007 KemI revised wqs from 2004 on behalf of the Swedish Environmental Protection Agency.
The following document contains descriptions of the methods for devising the guide values on each occasion:
Description of the wqs in 2004
Description of the wqs in 2007
The wqs are to be regarded as a tool in assessing the environmental quality in Swedish watercourses. There is guidance on how they can be used on the Swedish Environmental Protection Agency website.
For each individual substance there is a record of the properties of the substance and what calculations have been performed to obtain the wqs. All the records are collated in a PDF file. Records of wqs for plant protection products in surface water.