Walter Giger

Walter Giger (6 September 1943 – 6 November 2025) was a Swiss chemist. He worked at the Swiss Federal Institute of Aquatic Science and Technology (Eawag), where he was the head of the division ''Chemische Problemstoffe''. He was a professor for environmental chemistry at the ETH Zurich from 1995.

Giger was a pioneer who advanced the field of trace organic analysis and its application to significant environmental problems. His research topics included development of analytical techniques for identification of organic pollutants in drinking water, wastewater and natural waters. He investigated their sources, occurrence and fate. In 1984, he discovered that in wastewater treatment plants nonylphenol ethoxylates are transformed to 4-nonylphenols, which are toxic to aquatic life. After several additional studies the use of nonylphenols and nonylphenol ethoxylates was restricted in the European Union in 2003. Provided by Wikipedia