The distribution of polychlorinated biphenyls (PCBs) in the surface waters of the Atlantic shows concentration maxima in latitudes of high net precipitation and a minimum in the midlatitudes. Very low PCB concentrations are found in the South Atlantic. Since the nonvolatile inorganic radionuclide distribution in the Atlantic shows no dependence on precipitation patterns, codistillation with evaporating water must be a major factor in determining the distribution of PCBs....