If you look at the aerial photographs of I-80 in Utah around Salt Lake, near Grantsville, UT, you could potentially see that in some years, the lake "extends" to the south of I-80, whereas in others, the area may be completely dry.
https://maps.google.com/maps?q=40+39+47+N,+112+21+31+W
There was a lot of water there this late June 2013, but, IIRC, a couple of years back, it was almost completely dry.
In general, from the point of view of whether the said smaller portions of the Salt Lake have anything in it that's very harmful to humans, is it safe to try to bathe in such smaller portions of the Great Salt Lake?