Ecotoxicological evaluation of caffeine and its derivatives from a simulated chlorination step

Caffeine is ubiquitous in surface and ground waters and it has been proposed as a marker of the anthropogenic pressure on the environment. Sewage treatment plants based on active sludges seem to be not very efficient in its complete removal from effluents while addnl. disinfection treatments by chlorination are able to do it. In a simulation of the chlorination step herein we report that caffeine is transformed in six byproducts: 8-???chlorocaffeine, 1,???3-???dimethyl-???5-???azabarbituric acid, N,???N'-???dimethylparabanic acid, N,???N'-???dimethyloxalamide, N-???methylurea and N,???N'-???dimethylurea. The ecotoxicity of caffeine and identified compds. was evaluated on the rotifer Brachionus calyciflorus and the alga Pseudokirchneriella subcapitata to assess acute and chronic toxicity, while SOS Chromotest and Ames Test were used to detect the genotoxic potential of the investigated compds. Moreover, we assessed the possible antigenotoxic effect of the selected compds. using SOS Chromotest after co-???incubation with the std. genotoxin, 4-???nitroquinoline 1-???oxide. Chronic exposure to these compds. caused inhibition of growth population on the rotifer while the algae seemed to be unaffected. Results indicated that caffeine (1)???, N,???N'-???dimethyloxamide (4) and N,???N'-???dimethylparabanic acid (5) reduced ??-???galactosidase activity in comparison with pos. control, both at 1 and 5 mg???/L of 4-???NQNO with a good dose-???response.