In terms of hazards of the sediments it seems to be the highest in the sediment traps and pond 1 but low in the major part of the wetland system with the assessment methods employed herein and the ranking scheme employed. There is clearly a need for further studies for example by using bioassays with ecologically relevant sediment-dwelling test organisms such as C. riparius and L. variegatus, mechanistically different genotoxicity tests and methods for detecting endocrine-disrupting chemicals. Still, we recommend, considering the toxic effects observed in this study that hazard assessments of sediments from other treatment wetlands are conducted promptly. A suitable test battery for preliminary screening should at least include the umu test using a liquid/solid ration of 2:1 for genotoxic effects and a direct contact toxicity test with a sediment dwelling organism for example H. incongruens as it enables measurement of both an acute and a chronic effect in a short period of time.