Organochlorine pesticide levels in Ottawa drinking water, 1976.

Duplicate samples of Ottawa drinking water were collected once a month during 1976 and analyzed for organochlorine pesticides. The samples were analyzed by gas chromatography--mass spectrometry, and pesticides were identified by comparing their retention times, coupled with selected ion monitoring, with those of known standards. The pesticides detected and their mean concentrations in parts per trillion were aldrin (0.9), heptachlor epoxide (3), heptachlor (0.6), alpha-BHC (6), gamma-BHC (3), endrin (4), dieldrin (1), o,p'-TDE (1), o.p'-DDT (3), and o,p'-DDE (0.2).