Desalination and seawater quality at Green Point, Cape Town: A study on the effects of marine sewage outfalls
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Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Academy of Science of South Africa (ASSAf)
Abstract
This paper presents our collection methods, laboratory protocols and findings in respect of sewage pollution
affecting seawater and marine organisms in Table Bay, Cape Town, South Africa, then moves to consider their
implications for the governance of urban water as well as sewage treatment and desalination. A series of seawater
samples, collected from approximately 500 m to 1500 m offshore, in rock pools at low tide near Granger Bay,
and at a depth under beach sand of 300–400 mm, were investigated for the presence of bacteriological load
indicator organisms including Escherichia coli and Enterococcus bacteria. A second series of samples comprised
limpets (Patella vulgata), mussels (Mytilus galloprovincialis), sea urchins (Tripneustes ventricosus), starfish
(Fromia monilis), sea snails (Tegula funebralis) and seaweed (Ulva lactuca), collected in rock pools at low tide
near Granger Bay, and sediment from wet beach sand and where the organisms were found, close to the sites
of a proposed desalination plant and a number of recreational beaches. Intermittently high levels of microbial
pollution were noted, and 15 pharmaceutical and common household chemicals were identified and quantified in
the background seawater and bioaccumulated in marine organisms. These indicator microbes and chemicals point
to the probable presence of pathogens, and literally thousands of chemicals of emerging concern in the seawater.
Their bioaccumulation potential is demonstrated.
Description
Keywords
Microbial pollution, Pharmaceuticals, Perfluorinated compounds, Common household chemicals, Marine organisms
Citation
Petrik, L. (2017). Desalination and seawater quality at Green Point, Cape Town: A study on the effects of marine sewage outfalls. South African Journal of Science, 113(11/12): Art. #a0244