William J. L. Sladen

William Joseph Lambart Sladen MBE (19 December 1920 – 29 May 2017) was a Welsh American naturalist who was an Antarctic explorer and a specialist on polar bird life.

His discovery in the 1960s that DDT residues could be found in adelie penguins contributed to the banning of DDT in the U.S.[1][2] Sladen was born in Wales and trained in medicine with an MD from London and a Ph.D. in zoology from Oxford and joined a research team to the Antarctic in 1948 as part of the Falkland Islands Dependencies Survey.

He moved to the United States in 1956 and taught behaviour and ecology at the Johns Hopkins University School of Public Health.

A film on his studies Penguin City was produced in 1971 with narration by Charles Kuralt and broadcast by CBS.

He retired to Fauquier County in 1990 where he worked as the director of the Clifton Institute, a research station north of Warrenton Virginia.