The disposal of treated and untreated sewage near shellfish harvesting areas is a global concern. Discharged sewage may be contaminated with enteric viruses present in human faeces. Bivalve molluscs, in turn, act as vectors for enteric viruses through bioaccumulation and retention of these viruses during the filter-feeding process, resulting in outbreaks of infections due to the consumption of contaminated shellfish. This review was conducted using peer-reviewed articles published from 2012 until September 2022, obtained from online databases such as Google Scholar, Scopus, and Science Direct, highlighting the challenges that the shellfish industry is faced with concerning pollutants ending up in the shellfish production areas. Developed countries have made some advancements by upgrading sewage infrastructures, which reduced viral loads in sewage. However, it is difficult to measure the significance of these improvements, as there are no regulations in place which stipulate the permissible limits for viruses. In most developing countries, including South Africa, there is a lack of effective management plans for virus monitoring in shellfish harvesting areas. The findings of this study indicated a need for extensive research on the origin of viruses, their interactions with other organisms within the marine ecosystem, the quantification of viruses within the Saldanha Bay harbour, and the development of virus management plans which currently are non-existent.

Rivers are crucial hydrological cycle components, supporting ecosystems and human activities. Managing and protecting river water quality is essential. Diatoms, microscopic algae, are widespread and sensitive to changes in water quality, making them effective bioindicators. This study focused on the Kuils River in the Western Cape, South Africa, where diatom sampling was conducted at four sites. Their communities are affected by different physicochemical parameters, such as changes in pH, salinisation, eutrophication, and organic enrichment. A total of 98 diatom species were identified. The Omnidia software was used to calculate the Generic Diatom Index, Specific Pollution Index, and Trophic Diatom Index. Historical physicochemical data such as pH, chemical oxygen demand, and phosphorus were obtained from the Department of Water and Sanitation between 2019 and 2021 and were used to provide a reference for comparing diatoms. The results showed clear signs of pollution, as shifts in diatom species composition were observed. Pollution-tolerant species such as the Nitzschia palea (Kützing) W Smith 1856, Navicula viridula (Kützing) Ehrenberg 1838, Eunotia bilunaris (Ehrenberg) Schaarschmidt 1880, and Ulnaria ulna (Nitzsch) Compère 2001 dominated, while less pollution-tolerant species like Gomphonema parvulum f.saprophilum Lange-Bertalot and E. Reichardt 1993 and Stephanocylus meneghinianus (Kutzing) Kulikovskiy, Genkal, and Kociolek 2022 were less abundant. Both diatom indices and physicochemical data indicated poor water quality in the Kuils River. The study concludes that diatoms are a valuable tool for biomonitoring river water quality and recommends their use alongside traditional physicochemical methods for future assessments of river systems.

Grey water as opposed to blackwater is generally assumed to be a ‘safer’ and more acceptable wastewater source that could be considered for reuse (Birks & Hills 2007). This is mainly due to a common misconception that its microbial load is lower compared to that of blackwater (domestic sewage) (Birks & Hills 2007). This study was aimed to determine the presence of microbial contaminants, specifically pathogens, in stagnant grey water in the RR Section in Khayelitsha, Western Cape. The Most Probable Number (MPN) technique was conducted to determine faecal coliform (FC) and E. coli (EC) counts in the samples, respectively. The API 20E and the RapID™ ONE systems were used to identify possible pathogenic Gram-negative microorganisms, while the isolated Gram-positive microorganisms were identified with the BBL Crystal™ Gram Positive (GP) Identification (ID) system. The highest FC and EC counts observed during this period were recorded as 2.8 × 10⁷ microorganisms/100 mℓ (Site F, week 5), respectively. The RapID ONE and the API 20 identification systems mostly identified Escherichia coli, Klebsiella species and Enterobacter cloacae, amongst others while the BBL Crystal™-GP-ID system mostly identified Corynebacterium and Bacillus species. The presence of these organisms raises health concerns for the community of RR Section.

Bivalve molluscs are a good source of high quality protein and perform important ecological functions. Their ability to bioaccumulate materials in their soft tissues makes them suitable aquatic species for biomonitoring of environmental conditions. The discharge of treated and untreated sewage into the bivalve-growing areas is a concern. The aim of this study was to investigate the prevalence of bacterial microbiota in shellfish farms in Saldanha Bay harbour using pathogens commonly associated with shellfish-related foodborne disease outbreaks. Seawater and mussel samples were collected from five sampling points located in three sampling locations. Oyster samples were collected from the harbour deck immediately after harvesting by the farmers. The most probable number (MPN) method was used to enumerate E. coli and faecal coliforms. Cultural methods were used for the detection of Salmonella and Vibrio spp. The E. coli concentrations for 15 March and 14 July are <0.18 MPN/100ml at all sampling sites and for 25 August, <0.18 MPN/100ml for all sampling sites except sampling site SP2 (0.2 MPN/100ml). Spikes were observed on the total MPN counts in winter. Salmonella and Vibrio spp. were not detected. However, other bacterial species were identified through their phenotypic profile using the VITEK 2 system. Based on the low E. coli-MPN concentrations, the study concluded that the molluscs were safe for human consumption. Further studies need to be conducted on the bacterial species identified.

Rivers are crucial hydrological cycle components, supporting ecosystems and human activities. Managing and protecting river water quality is essential. Diatoms, microscopic algae, are widespread and sensitive to changes in water quality, making them effective bioindicators. This study focused on the Kuils River in the Western Cape, South Africa, where diatom sampling was conducted at four sites. Their communities are affected by different physicochemical parameters, such as changes in pH, salinisation, eutrophication, and organic enrichment. A total of 98 diatom species were identified. The Omnidia software was used to calculate the Generic Diatom Index, Specific Pollution Index, and Trophic Diatom Index. Historical physicochemical data from the Department of Water and Sanitation provided a reference for comparing diatom communities. The results showed clear signs of pollution, as shifts in diatom species composition were observed. Pollu-tion-tolerant species like the Nitzchia palea, Navicula viridula, Eunotia bilunaris, and Fragilaria ulna dominated, while less pollution-tolerant species like Gomphonema parvulum and Cyclotella meneghiniana were less abundant. Both diatom indices and physicochemical data indicated poor water quality in the Kuils River. The study concludes that diatoms are a valuable tool for biomonitoring river water quality and recommends their use alongside traditional physicochemical methods for future assessments of river sys-tems.