Pass Lake in Deception Pass State Park is being closed to all recreational use due to high levels of microcystins, a toxic cyanobacteria. The safe level is about six; the lake is over 1,000.
Microcystins are a slow-acting chronic toxin that affect the liver. With levels that high, we do not want visitors to be exposed to the toxin at all. The closure means no fishing, wading, swimming, or pet use.
The lake was at the warning stage a few weeks back because of slightly elevated numbers. The levels dropped the past couple of weeks below the recommended safe limit, but jumped this week to record levels.
This is a problem that is increasing in just the past few years. We are conducting research into the source of the problem, but have found no answers yet. Although the toxin is microscopic, the green paint-like scum in the lake tends to be a visual indicator. Right now the scum is extensive along the shoreline, depending which way the wind is blowing.
Skagit County Health is testing the lake weekly to monitor the toxin.