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SANOCEAN-South Africa - Norway co-operation on ocean research including blue economy, climate change, the env

Marine Sewage Outfalls - Environmental Impact Evaluation

Alternative title: Marine Kloakkstrømmer - Evaluering av Miljøpåvirkning

Awarded: NOK 1.6 mill.

The drought in the Western Cape in 2018-2019 led to the proposal to produce drinking water for the City of Cape Town by seawater desalination plants. The city discharges a high volume of untreated sewage effluent into the ocean via the marine outfalls located around the Cape Peninsula. If not treated properly, reclaimed water from the desalination plants can act as a possible exposure pathway to a high number of emerging contaminants such as pharmaceuticals and their metabolites to the population of Cape Town. In the project water samples and aquatic organisms has been collected and analyzed for common contaminants found in sewage (chemical monitoring) both in Cape Town and Stavanger. Caging studies with mussels has been conducted in the vicinity of sewage outlet pipes in both cities to look at biological effects (biological monitoring). In addition, a laboratory exposure study was conducted with worms (Nereis virens) exposed to a single pharmaceutical, namely amitriptyline. The combination of chemical and biological analyses has provided a good evaluation of the health of the ocean around Cape Town and around the sewage outlet for the Stavanger region. The findings from the studies show that a range of pharmaceuticals are present in detectable concentrations in the ocean around Cape Town and that the chemicals bioaccumulates in biota. Equivalent studies from Stavanger show fewer pharmaceuticals at detectable concentrations in the effluent from the sewage treatment plant. Generally, for both sites is that sediments have a much higher concentration of pollutants than concentrations found in water samples, which means that biota living on and in the sediments are to a larger degree exposed to pollutants. Bioaccumulation has been confirmed both in samples collected at locations around the sewage outlets in Cape Town and in laboratory exposure studies conducted in Stavanger. Caging studies will most likely also confirm this when that work is finalized. These findings highlight the need for better treatment plants for sewage that can remove pharmaceuticals. This should also be aided by developing pharmaceuticals that have a shorter life time in the environment after use.

The results obtained in the project have been disseminated in peer review journals, at scientific conferences and to the public through chronicles (kronikker) in newspapers and forskning.no. Our first report from the project (Ojemaye et al. Sci. Total Environ. 2020, 738, 140346) got the attention of the city council of Cape Town who attacked the study due to the results showed that the water and sand in and around one of their more popular beaches do not have the quality one would like, and we do find bioaccumulation of contaminants in biota from that ocean side. This resulted in a rather unusual publication in a scientific journal by Colenbrander et al. (Sci. Total Environ. 2021, 755, 142576) where they challenged our findings. The points they were challenging was related to the source of the pollutants and the challenges were answered by us in a second paper in the same journal (Sci. Total Environ. 2921, 778, 146057). This extra attention brought by the challenge from Colenbrander et al. helped spread the results of our research even further. The panel debate in December 2021 entitled From Toilet to Sea: Research collaboration to ensure safe water organized by Science Forum South Africa was an excellent opportunity to disseminate results and inform policy makers from around the world (predominantly African policy makers). We also followed that session up with a chronical in forskning.no. so that Norwegian public also could get an update on the situation related to pharmaceuticals in the marine environment. Due to delays in sample analysis (analytical chemistry) we do have results that have not been disseminated to date. This will be done during 2023 and will both be in the form of scientific articles in peer review journals and as talks. Worth mentioning is that the results from the project will be presented at SETAC Europe in Dublin this May as a platform lecture. The SANOCEAN project will be followed up in the INTPART project that is based on this project. The INTPART project will run through 2023 and results from the SANOCEAN project will be discussed and shared at our workshop in Cape Town in March and at other events organized by INTPART.

The ongoing drought in the Western Cape has led to the proposal to produce drinking water for the City of Cape Town by seawater desalination plants. The City discharges a high volume of untreated sewage effluent into the ocean via the marine outfalls located around the Cape Peninsula. If not treated properly, reclaimed water from the desalination plants can act as a possible exposure pathway to a high number of emerging contaminants and their metabolites. In this project, water samples and aquatic organisms will be collected and analysed for common contaminants found in sewage (chemical monitoring). Also a caging study with mussels will be conducted in order to look at biological effects (biological monitoring). The combination of these analyses will provide a good evaluation of the health of the ocean around Cape Town. The findings from the project will be of good use when the city is planning new desalination plants and sewage treatment plants. A sewage plume model will be made, making it possible to predict where the plume will go under different weather conditions. Communication both with the lay public, politicians and scientists will be an important part of the project. Dissemination of results will take place by means of YouTube movies, articles online, newspaper articles, public speaking, and scientific articles. An app will also be developed in the project that will give a real time update on the pollution situation at the city beaches at any given time.

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SANOCEAN-South Africa - Norway co-operation on ocean research including blue economy, climate change, the env

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