Fluorescence as a tool for tracing the organic contamination from pulp mill effluents in surface waters

Three-dimensional fluorescence spectra of water samples from an eucalyptus bleached kraft pulp mill and from a river, upstream and downstream of the d ischarge of the effluent, revealed the existence of a peak at lambda (exc) = 280 nm and lambda (em) = 340 nm (Delta lambda = 60 nm), characteristic of effluent's organic matter. Humic substances were isolated from the effluen t by sequential adsorption onto resins XAD-8 and XAD-4 in series. Their syn chronous fluorescence spectra with Delta lambda = 60 nm do also exhibit an intense signal at lambda (exc) = 280 nm (approximate to 300 nm in the humic acid fraction). The peak is absent in the spectra of humic substances isol ated from a non-polluted site of the river, but it is clearly seen in the s pectra of the humic substances from a site downstream of the discharge of t he effluent. Synchronous fluorescence spectra (Delta lambda = 60 nm) of wat er samples from the river and its lagoon were recorded and revealed to be a n easy and fast way of tracing the organic contamination from the effluent.