What to do Next

What to do if you think you may have blue-green algae in a water supply.

•  Step 1 - Identify the algae to confirm if you do have potentially dangerous algae.
•  Step 2 - Sample for algae.
•  Step 3 - Where to send the sample.
•  Step 4 - Interpreting the lab. test results.
    Step 5 - How to keep your stock and other water users safe from toxic algae.

What to do if you discover algae?


Blue green algae cells are microscopic and are grouped in colonies and chains. Blue green algal scums form when large numbers of algae float to the water surface using gas vesicles to gain maximum sunlight. Wind pushes the floating algae across the water concentrating scums against leeward shorelines. Scums can vary from paint like accumulations at water surfaces to small green floating dots (blue green algal colonies) at the beginning of the bloom. Scums are often green or blue green, but can also be white, brown, blue, yellow-brown or red. Swirling patterns (of a mixture of these colours) can be caused by wind movement, and other blooming algae (Mitrovic, 1997).

STEP 1 How do I know if I have algae?

Take the Quick ID test and perhaps the Detailed ID Test to check if you need to take further action to identify the algae.

If you believe that any of the information given above relates to what you may have seen, then the only way to be sure is for the algae to be assessed under a microscope. This will require contacting an appropriate authority in your area. In the Murray RACC area you may contact in NSW the Department Land and Water Conservation or in Victoria, Goulburn Murray Water. Their details are below:


Position and Location

Contact Details

Dept Land and Water Conservation

Water Quality Officer, Albury

Ph 02 6043 0100

Fax 02 6041 4223

Goulburn Murray Water

Natural Resources Management Officer, Tatura

Ph 03-5833 5731

Fax 03-5833 5739

If the bloom is in a river or creek then when you phone please be ready to provide details of the location, appearance and extent of the algae. A sampling officer will then be dispatched to assess and sample the algae to determine whether it's blue green algae. If the bloom is in a farm dam and you would like it checked then we'll ask you to bring a sample in for testing. There is a charge for this service if the sample is collected for testing by the Department Land and Water Conservation (please ask for the latest quote).

STEP 2 How to sample for Blue Green Algae – on your farm

If you believe that one or more of your farm dams have algae then it may be beneficial for you to have it tested. If you are able to draw water from other unaffected dams (or another source all together, eg groundwater) for stock and domestic supply then you may choose to let the bloom complete it's growth cycle and dissipate. Assuming you don't have this ability then testing is recommended. For the purposes of this document we'll be referring to the DLWC procedure. This procedure will differ for Goulburn Murray Water, if you live in Victoria we recommend you contact them to determine their requirements on the number listed above. Moving along, in order to provide a sample for identification it'll be necessary to collect some of the algae in a bottle. The best bottle to use is a 250ml plastic screw top bottle supplied by the DLWC, which is available from any office in the Murray Region.

If you aren't able to get to an office to collect a jar, then it is recommended that you provide a sample in a glass jar (eg medium to large sized vegemite jar) that has been cleaned and rinsed well, or in a small soft drink bottle that again has been cleaned and rinsed well. Please be mindful that algae can affect you if touched or ingested so when you sample please wear a glove to avoid touching the algae and rinse the glove in fresh water before removing it. Also rinse the outside of the bottle in freshwater to avoid touching the algae accidentally after you have removed your glove. Please write the date and collect time on the bottle in a black texter. The sample should be chilled and delivered to the nearest DLWC office as soon as possible in an esky with a frozen ice brick in order to keep it cool. We will require your name, address and other contact details in order to be able to return the results and provide an invoice to you after analysis. While we've mentioned that the DLWC can provide a testing service, a number of other laboratories can provide a testing service for the algae and these are listed below:

STEP 3 - Where to send the sample

Laboratory:DLWC Water Environment Lab
Address:4 Guess Ave Arncliffe NSW 2205
Contact:Jon Holliday
Phone02-9597 4444
FAX02-9597 4808 02-9597 6253 (urgent samples)
ServicesAlgal Identification & counting.
NATA registered ID: CountingYes

Laboratory:Water Ecoscience
Address:68 Ricketts Rd Mt Waverley VIC 3149
Contact:Dr Kumar Elizer
Phone03-9550 1000
FAX03-9543 7372
ServicesAlgal identification & counting. Toxicity testing by mouse bioassay.
NATA registered ID: CountingYes

Laboratory:Murray Darling Freshwater Research Centre
Address:Ellis St Thurgoona NSW 2640
Phone02-6043 1002
FAX02-6043 1626
NATA registered ID: CountingNo

Laboratory:State Chemistry Laboratory
Address:cnr Sneydes & South Rd Werribee VIC 3030
Contact:Carl Raynor
Phone03-9742 8755
ServicesHPLC analysis for microcystins in scums & water.
NATA registered ID: Counting

Laboratory:University of New England
Address:Molecular Cellular Biology Armidale NSW 2350
Contact:Mandy Choice
Phone02-6773 2706
FAX02-6772 8235
ServicesToxicity testing by mouse bioassay.
NATA registered ID: Counting

Laboratory:AWT Ensight
Address:51 Hermitage Rd West Ryde NSW 2114
Contact:Peter Hawkins
Phone02-9334 0935
FAX02-9334 0973
ServicesAlgal identification & counting. Toxin analysis & mouse bioassay.
NATA registered ID: CountingYes

Laboratory:WSL Consultants Pty Ltd.
Address:2-8 Harvey St Richmond VIC 3121
Contact:Dr K Power
Phone03-9429 4666
FAX03-9429 2294
ServicesAlgal identification & counting..
NATA registered ID: CountingYes

Laboratory:Envirogen Microbiological Laboratory
Address:Hazelwood Rd Traralgon VIC 3844
Contact:Mr Chris Wood
Phone03-5172 1555
FAX03-5174 9320
ServicesIdentification & counting of blue-green algae only.
NATA registered ID: CountingYes

Laboratory:Para-Tech Veterinarian Services
Address:5 Grant Drive Benalla VIC 3673
Contact:Tricia Veail
Phone03-5762 1515
FAX03-5762 1515
ServicesAlgal identification & counting.
NATA registered ID: CountingNo

Laboratory:Ecowise Environmental Ltd
Address:16 Lithgow St Fyshwick ACT 2609
Contact:Ms C Boatwright
Phone02-6285 7256
FAX02-6285 7256
ServicesAlgal identification.
NATA registered ID: CountingYes

Laboratory:State Water Laboratory
Address:Salisbury SA 5108
Contact:Michael Burch
Phone08-8259 0352
ServicesAlgal identification & counting. Toxicity testing by mouse bioassay & HPLC.
NATA registered ID: CountingYes

Laboratory:Australian Water Quality Centre
Address:Hodgson Rd Bolivar SA 5110
Contact:Mr W Emmett
Phone08-8259 0211
FAX08-8259 0228
ServicesAlgal identification & counting.
NATA registered ID: CountingYes

If you choose any of these laboratories, please contact them directly for their procedures for sampling and transport to the laboratory for testing.

STEP 4 - Interpreting the results, what does it all mean?

You'll receive the results of the testing per sample (if you sent more than one) and normally counts will be in cells of blue green algae/millilitre of water (cells/mL). The algal species will be broken down with the dominant algae displaying the highest cell counts. The table below shows the range of total blue green algal cell counts and what they may mean to you. Normally counts in the ‘High Alert' range are the most important, however ‘Medium Level' counts should also be taken seriously as the bloom may still be developing and before long could be at ‘High Alert' if conditions are suitable.

Alert Level

Cell Count Range


No alert

0 –500 cells/mL

Only background levels of algae present in the sample


500- 2000 cells/mL

Algae should not be noticable visually at these concentrations and toxicity impacts shouldn't be of concern unless the bloom has fallen from high alert levels only recently


2000-15000 cells/mL

Algae will become noticable in this range depending on the species and odours may develop. Toxicity may be a concern, especially if counts are falling from higher counts previously


15000 cells/mL and above

A bloom is present in the water body and toxicity effects are very possible depending on algae species. Stock and domestic use should be restricted from the water body unless appropriate water treatment is possible.

Other Important Contacts

NSW Agriculture and the Rural Lands Protection Board can assist with information regarding the potential impacts upon stock as a result of the algae. NSW Health can provide information on human impacts from blue green algae for domestic supplies.

What Now?

Assuming you have received a result in the High Alert range it is important that you get in contact with the relevant authorities mentioned in this document. They will be able to assist you with management actions specific to your situation that should lessen the impact of the algae upon you.


Mitrovic, S. (1997) " What Scum is That? NSW Dept Land and Water Conservation.




? 2002. NSW Murray Regional Algal Coordinating Committee, MRACC. Unless otherwise specified, maps and images are copyrighted to Department of Land and Water Conservation, NSW.