Ever since organisers and participants of the side‐effect workshops recognized the need for “Recommendations”; they faced a double task, namely to be rather conservative, in order to satisfy the general need for reliable and stable guidelines, and to be progressive, to give appropriate credit to new scientific developments and to allow flexibility for updating concepts, techniques or evaluation schemes. Both aspects will be included in the following report, but the main emphasis will be on the discussion of future developments in order to keep this particular segment of environmental research in a lasting dynamic state.