Instrumental neutron activation analysis has been successfully employed in three distrinct acid precipitation studies. These include the determination of ten (Al, Br, Ca, Cl, Cu, I, Mg, Mn, Na and V) elements in urban rainfall, elevated aluminum concentrations in acidified lakes and major ions (Ca, Cl, K, Mg and Na) in small-mouth bass kept in controlled pH environments. Quality control was assured by analyzing two certified standard reference materials prepared by the National Bureau of Standards (NBS 1643a) and National Research Council of Canada (hepatopancreas TORT-1 marine biological tissue).