Eutrophication control remains a critical phase in the management of freshwater ecosystems. A fundamental approach is limitation of nutrients through diversion or advanced waste treatment. However, trophic state improvement may not be obtained in systems with poor flushing characteristics or in systems that recycle large quantities of nutrients from enriched sediments. In such cases in situ treatment is a possible option. The authors conducted a systematic laboratory evaluation of a group of potential phosphorus inactivants. Zirconium tetrachloride, zirconyl chloride, lanthanum (La) rare earth carbonate, lanthanum rare earth chloride, sodium aluminate, aluminum sulfate, sodium tungstate, titanium sulfate, and a crude zirconium refinery waste were evaluated for P-removal efficiency and toxicity to aquatic organisms.