Home > Coastal and floodplains > Estuaries > Factsheets > Water Quality

Estuaries in NSW

Estuarine Water Quality

Disease Organisms

Disease causing micro-organisms enter estuaries via sewage, animal faeces or in urban runoff. Levels of coliform bacteria (eg Escherichia coli) are monitored as an indicator of faecal contamination. This is an indirect measure of the possible presence of water-borne human pathogens, such as the Hepatitis A virus.

The presence of faecal material in estuarine waters tends to be higher during heavy rain, because of sewer overflows and urban runoff. Human pathogens can endanger people in direct contact with the water (eg swimmers), or those eating contaminated filter-feeders (eg oysters), which can concentrate bacteria and viruses. Introduced pathogens can affect flora and fauna.

[Next Page - Salinity]