Sediment is one of the most important media in the environment. Sediment could provide habits and food for aquatic wildlife and plays a crucial role in the cycles of nutrients in the aquatic ecosystem. Nevertheless, pollutants released from industries would contaminate the aquatic sediments. Contaminated sediments might directly or indirectly affect fishery products which we consume daily. Therefore, suitable ways are needed to manage sediments. The Environmental Protection Administration (EPA) of the Executive Yuan had declared some regulations to manage qualities of sediments. In order to make clear of sediment quality in Taiwan, it is necessary to assist competent authorities to detect and report sediments qualities and further to carry out management strategy and treatment technology evaluation; therefore, the EPA of the Executive Yuan offered the opportunity (this project) to study those issues. In this project, the main works were (1) establishing sediment quality on-line report and management system and analyzing relevant environmental and geographic information to identify sediments with higher potential of pollution, (2) investigating the occurrence of methyl mercury in Taiwanese aquatic environments to serve as a reference when the standard of sediment quality need to be modified, (3) developing contaminated sediment treatment, disposal and reuse strategies (4) developing relevant ecological risk assessment guideline for sediment such as determination of contaminants of potential concern and receptor of concern, selection of assessment endpoints and measurement endpoints, and development of conceptual site model. Achievements of this project are (1) helping EPA to review sediment sampling projects on 89 waterbodies, improving Sediment Quality on-line Report and Management System, and establishing Contaminated-Sediment Decision Resourses System; (2) completing the investigation of the occurrence of methyl mercury in Taiwanese aquatic environment, analyzing factors that influence the formation of methyl mercury and giving a suggestion about whether methyl mercury serves as one of the sediment quality standard terms; (3) completion of contaminated sediment treatment, disposal and reuse strategies for irrigation canals; (4) the sediment ecological risk assessment (ERA) guideline for problem formulation phase has been developed. This guideline includes determination of contaminants of potential concern and receptor of concern, selection of assessment endpoints and measurement endpoints, and development of conceptual site model. Besides, this project also conduct ERA in Siangshan Wetland on the basis of this guideline.

sediment, management strategy, quality guidelines, risk assessment