Trichlorethylene (TCE) is the most frequently found contaminant at National Priority List (NPL) Sites. In the Phase I investigation, the rapid destruction of 100 ppm TCE in waters derived from sampling wells of a Superfund Site was demonstrated utilizing the equivalent UV radiation present at one Sun intensity. In one of the waters, TCE destruction was anomalously slow and photocatalyst deactivation was premature. This was attributed to the photoelectroplating of chromium or heavy metals onto the photocatalyst powder. This effect can be used to advantage for the removal of toxic metal ions and organics from water. The proposed Phase II study will comprehensively investigate the photocatalytic decomposition of various concentrations of TCE in the presence of the Metal ions Pb+2, Cd+2, Cu+2, Hg+.2, Cr+6, Cr+3, Fe+2, and Fe+3. These metals are found in the first 37 most frequent substances, out of 472 identified, at NPL sites. Various process strategies will be investigated for effecting the simultaneous or sequential removal of organic compounds and metal ions from contaminated waters at NPL Sites vis photocatalysis. The investigators expect to demonstrate and elucidate photocatalytic processes for the simultaneous and/or sequential removal of co-contaminants such as halocarbon and heavy metals from waters at Superfund Sites. This technology has the potential to destroy in situ, almost all aqueous organics and to remove heavy metals. Some of the commercial applications are in mitigating water pollution, purifying municipal and residential water supplies, and metals removal from mining activities. Federal government applications exist in the purification of waste-waters contaminated by nerve-agents, propellants, explosives, and radioactive metals.