2007/11 – Frankston (Victoria) – Manganese, Iron, Turbidity

Frankston (Victoria) – Manganese

Another routine monitoring program sample result that was not notifi ed to the DHS at the time was for high manganese. The sample was taken on 15 February 2007 in the Frankston locality. The health guideline for manganese is 0.5 mg/L and the sample had a result of 5.6 mg/L. This was a totally unexpected/unusual result. All previous (many years) and subsequent manganese results at the same site in the Frankston locality (and in all localities supplied from the Cardinia Reservoir) have been considerably less than the guideline limit, i.e. less than 0.5 mg/L and typically very low values in the range 0.002 to 0.007 mg/L. The high result was considered to be an outlier which was not representing the true level of manganese in the drinking water – no reason for the high result could be determined. Any future high result for a health related parameter in the ADWG will be notified to the DHS at the time the result is known.


Manganese: ADWG Guidelines 0.5mg/L. ADWG Aesthetic Guideline 0.1mg/L
Manganese is found in the natural environment. Manganese in drinking water above 0.1mg/L can give water an unpleasant taste and stain plumbling fixtures and laundry.

Frankston – Victoria – Iron

2006/7: Frankston (Victoria)  – Iron 1200ug/L (Highest level only)

2008/9: Frankston (Victoria)  – Iron 480ug/L (Highest level only)

Based on aesthetic considerations (precipitation of iron from solution and taste),
the concentration of iron in drinking water should not exceed 0.3 mg/L.
No health-based guideline value has been set for iron.

Iron has a taste threshold of about 0.3 mg/L in water, and becomes objectionable above 3 mg/L. High iron concentrations give water an undesirable rust-brown appearance and can cause staining of laundry and plumbing fittings, fouling of ion-exchange softeners, and blockages in irrigation systems. Growths of iron bacteria, which concentrate iron, may cause taste and odour problems and lead to pipe restrictions, blockages and corrosion. ADWG 2011

Frankston – Victoria – Turbidity

2010/11: Frankston (Victoria) – Turbidity 8.1 NTU (Maximum detection during year)

Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment
process to address identified risks from Cryptosporidium and Giardia, it is essential
that filtration is optimised and consequently the target for the turbidity of water leaving
individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time
Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with
chlorine unless a higher value can be validated in a specific context.

Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the
consumer’s tap.