Toxicity evaluation of natural and synthetic phenanthrenes in aquatic systems

Seven natural 9,10-dihydrophenanthrenes were isolated from the common reed Juncus effusus by means of chromatographic processes and identified by spec troscopic means. Furthermore, mimics of natural isolated compounds were syn thesized to try to evaluate the influence of functional groups on the dihyd rophenanthrene skeleton. Syntheses of compounds were based on the cross-cou pling of 1-(2-iodo-5-methoxy)phenyl-ethanol with variously substituted iodo benzenes by zerovalent nickel. All the chemicals were tested to evaluate th eir effects on freshwater organisms from different trophic levels. Toxicity tests were performed on reducers (the bacterium Escherichia coli); produce rs (the alga Raphidocelis subcapitata, previously known as Selenastrum capr icornutum); and consumers including a rotifer (Brachionus calyciflorus), a cladoceran (Daphnia pulex), and an anostracan (Thamnocephalus platyurus). R esults suggested no one organism was uniquely sensitive to the chemicals te sted. Toxicity depended on the kind and position of substituents on the aro matic skeleton.