COPPER(I) COPPER(II) REACTIONS IN AN URBAN RIVER/

The bathocuproine spectrophotometric method for Cu(I) analysis was con siderably improved by pre-concentration on C-18 columns and selective elution into methanol:water (90:10); a detection limit of 0.1 mu g l(- 1) was found. Concentrations of Cu(I) in an urban river (2.4-7.5 mu g l(-1)) varied with solar UV radiation, measured at 365 nm. Mechanisms of photoreduction were studied through Cu(I) scavenging experiments, w hile the relative importance of particles, colloids and microorganisms were investigated through dilution/filtration, Cu(I)/Cu(II) speciatio n in the urban river appears to be altered under daylight conditions t hrough a photoreduction process involving Fe(II)/Fe(III), H2O2 and dis solved and colloidal organic compounds. Low oxygen conditions in the u rban river hinder reoxidation and lead to the high Cu(I) concentration s found.