Arbeitsgemeinschaft Rhein-Wasserwerke e.V. (ARW). Annual report 1991

This annual report covers the following topics: Yearly statement issued by the Rhine public utilities workshop (ARW) on measurements in the Rhine and Main rivers; development of harmful EDTA and NTA concentrations in the Rhine; impurification with harmful substances of the Rhine river in the Biebesheim region; processing of data for predictions about the migration of harmful substances in the Rhine; development and preliminary design of the Rhine alarm model's second version; experiences with the determination of enzyme activities for the Rhine population of microorganisms; riverbanks permitting soil infiltration - safe water resources - characterisation of the Oberwerth waterworks on the Middle Rhine; impurification of the Main and Nidda rivers with pesticides and traces of organic chlorine compounds in the Frankfurt area (1989-1991); curve of phosphor and nitrogen concentrations for the Lower Main and Nidda in the Frankfurt area; the 18O/16O method in hydrology. The appendix contains a summary of analytical findings in 1991, an outline of the measurements planned to be carried out in 1992 as well as a survey of the organisational setup of the Rhine public utilities workshop (ARW). (BBR)