Monitoring of marine areas in Arendal 2015-2016 – ecological status at discharge locations for municipal wastewater

Summary

It has been conducted a marine monitoring survey in Arendal in connection with discharges of municipal wastewater from Saulekilen and Narestø sewage plants. The purpose of the study was to obtain information on the ecological status and to assess how the status has changed over time. The survey is a part of authorities’ requirement of controlling such discharges, and is conducted in order to identify adverse effects and to implement eventual remedial work. The survey is also part of the implementation of the EU Water Framework Directive, which requires a management aiming at ensuring protection and sustainable use of all aquatic environments. According to this directive, all water bodies should be protected against degradation. This requires that all water bodies should have at least good ecological and good chemical status by 2021. The investigated areas are Utnes/Ærøy, Narestø and Barbu. The study included water masses (hydrography, nutrients and chlorophyll), soft bottom (fauna, sediment) and shallow water communities (algae and animals in the littoral zone). Contaminants were also investigated at the discharge point from Saulekilen sewage plant.