Atmospheric concentrations of toxaphene on the coast of Lake Superior

Thirty-seven air samples were collected from September 1996 through Decembe r 1997 at Eagle Harbor, Michigan to determine the atmospheric concentration of toxaphene near Lake Superior. The concentrations ranged between 0 and 6 3 pg/m(3), with most less than 20 pg/m(3), which agreed well with concurren t measurements over the lake and near Lake Michigan made by other research groups. These concentrations are significantly lower than those measured in 1988 and 1989 in Egbert, a small city in southern Ontario. The phase trans ition energy was calculated to be 47 kJ/mol, half the value calculated for the Egbert site; this disparity has been seen in comparisons of lakeshore a nd over-land values for other compounds. If temperature effects are removed , the average toxaphene concentration for the Eagle Harbor samples was 6.4 +/- 2.2 pg/m(3), which was lower than the 16 pg/m(3) average at Egbert, Ont ario. This difference in concentration may (or may not) be due to differenc es ill sampling dates or locations or in measurement techniques.