The most dilute lake in the world?

Lake Notasha, near the crest of the Oregon Cascade mountain range, is the most dilute lake known. The measured conductivity during two visits was 1.3 and 1.6 µS cm^-1 with a sum of base cations of 9 and 18 µeq L^-1; bicarbonate was the dominant anion. Most of the cations in the lake can be accounted for by evapoconcentration of precipitation, although input of weathering products cannot be excluded as a source. The topographic watershed has a mixed coniferous forest, but the physical setting of the lake apparently minimizes hydrologic and ionic contributions from the watershed. This feature makes lakes such as Notasha appropriate receptors for monitoring atmospheric contaminants.