The Commonwealth Environmental Water Office has released a factsheet—“Hypoxic blackwater events and water quality”—that describes a natural phenomenon now underway in the Murray-Darling Basin after heavy rains in the catchment: an inflow into the river system of tannins and other organic material. A resultant black appearance of water is caused by dissolved carbon compounds that rapidly deplete the volume of dissolved oxygen available to sustain fish and other living organisms.

Likely effects within Lake Alexandrina are not detailed but the advice does include: “Risks to human health are low if direct contact with blackwater is avoided. Thorough cleansing is advised after any contact with affected water and discoloured or dead fish should not be eaten because of possible health risks.”

Click here for a copy of the factsheet. The event is not expected to have a significant impact on our foreshore but residents should take note of any relevant advice in local media.

Chris Bagley,

Community Advisory Panel, DEWNR

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