"We can be confident that the water was not contaminated following the pest control operation," she said.
"The tiny detection in the first sample taken from the middle of the aerial drop is the equivalent of finding a single gram of 1080 in a 25m swimming pool, the size of the competition indoor pool in Whangarei.
"We know people have concerns about water quality after a 1080 operation, and we wanted to provide independent testing to show the water is safe and 1080 is not present in the awa in Russell Forest."
Ms Reed Thomas said DOC routinely had water tested by independent laboratories following 1080 operations. Samples were collected immediately when there was the greatest possibility of detecting contamination. The Ministry of Health's 2ppb precautionary standard had never been exceeded.
A further four samples, from Waikare streams, were tested to provide information for local iwi, and produced no detectable 1080.
Details of the pest species kill from the Russell and Cape Brett operations were due in coming weeks.