Data are from Jaffe, Parker, and Wilson (1982), Distribution of toxic 
substances in rivers, Journal of Environmental Engineering Division, 108:639-649.

Data are concentrations of aldrin and hexachlorobenzene (HCB) in nanograms per liter from ten 
surface water samples, ten middepth water samples, and ten bottom samples from the Wolf River
in Tennessee. The samples were taken downstream from an abandoned dump site previously
used by the pesticide industry. The samples were taken in order to test the hypothesis
that these substances are evenly distributed vertically in the river. (Differences in
density could lead to higher concentrations near the river's bottom.)

These data were taken from the web site OzData at 

   http://www.maths.uq.edu.au/~gks/data/