Australian Drinking Water Map

October 2020 + October 2021 – Marian WTP Cyanobacteria

Concentrations of blue-green algae (cyanobacteria total cells) for FY 2021 – 2022 are graphed in Figure 3 – 2.  Cyanobacteria total cell results for Nebo Rd WTP Raw River Water were generally less than 1000 cells/mL (similar to those for FY 2020 – 2021 and FY 2019 – 2020), except for May 2022 where there was a small increase to 1947 cells/mL. The results did not indicate blue-green algae blooms occurred at Dumbleton Weir. Cyanobacteria total cell results for Marian WTP Raw Water indicate there was a significant bloom in October 2021, with results reaching 689,423 cells/mL. A bloom also occurred in October of the previous year

2016/2018 – Marian (Queensland) – Lead

2013/2014: Marian Lead 0.0082mg/L (max), 0.003mg/L (av.)

2014/2015: Marian Lead 0.008mg/L (max), <0.003mg/kg (av.)

2016/2017: Miriani 1 Alice Street Marian Lead 0.04417mg/L (max), 0.0012mg/L (mean)

2016/2017: Miriani 2 Patricia CCT Marian Lead 0.01262mg/L (max), 0.00158mg/L (mean)

2017/2018: Marian Lead 0.00972mg/L (max), 0.00191mg/L (av.)

Patricia Cct

A concentration of 0.0126 mg/L for lead was reported for a sample collected from ‘Mirani 2 – Patricia Cct’ on 5 September 2016. This result was initially flagged as exceeding the ADWG health value of 0.01 mg/L and was therefore reported as a drinking water incident. Upon review of this incident it has been identified that this concentration did not in fact exceed the guideline when comparing the result once rounded to a precision level of one significant figure (0.01 mg/L) (as per guidance stipulated in page 165 of the ADWG).

Re-analysis of the original sample returned a lead concentration of 0.0085 mg/L. The re-sample results (for a sample collected from Mirani 2 – Patricia Cct on the 12 September 2016) returned a lead result of <0.001 mg/L.

Re-analysis results confirmed the original result was not due to analytical error and was unlikely to be due to contamination of the original sub sample at the laboratory. The original and re-analysis results indicate that the sample tap may have deteriorated prior to sample collection and contributed to the high lead result in the sample.

No corrective actions were taken as there was deemed to be no risk to public health.

Alice Street

A concentration of 0.0442 mg/L for lead was reported for a sample collected from the Mirani 1 – Alice Street drinking water sample point on 11 May 2017. This result exceeds the ADWG health value of 0.01 mg/L.

Re-analysis of the original sample returned a lead concentration of 0.0415 mg/L. The re-sample results (for a sample collected from the Mirani 1 – Alice Street sample point on the 8 May 2017) returned a lead result of <0.0005 mg/L.

Re-analysis results confirmed the ADWG health guideline exceedance. It was expected the original exceedance was the result of tap degradation. Following identification of the exceedance arrangements were made to replace the sample point tap with a brass tap.

2018/19: Marian 0.01255mg/L (max), 0.00106mg/L (av.)

May 30 2022: A lead result above the ADWG health guideline values was detected during routine sampling at Mirani 2 – Patricia Court. On the same day, a compliant result was recorded from Mirani 1 – Alice Street, suggesting that the breach was localised. As the sample point is at the end on the line, the reticulation system was flushed and resampling conducted. As the sample tap was only installed in 2021, the result is most likely caused by the tap being unused for extended periods, allowing sedimentation to form in the line, which is then disturbed when the water sample is taken, rather than contamination of the drinking water supply.
The sampling procedure for this site now includes a preliminary flush of the main through a 50mm offtake tap prior to sampling. Routine monitoring on the 6 June 2022 and follow up sampling on 10 June 2022 at Patricia Court and Alice Street, returned compliant results.

Lead Guideline reduced from 0.01mg/L to 0.005mg/L in June 2025. “The concentration of lead in water within premises may be higher, especially in older buildings, due to contact of the water with lead-containing plumbing products (enHealth 2021). A review found several Australian and international studies that detected up to 0.162 mg/L of lead in drinking water due to leaching from lead-containing plumbing materials including taps and lead service lines, suggesting that leaching of lead from lead-containing plumbing materials can be substantial (SLR 2023)… Based on health considerations, the concentration of lead in drinking water should not exceed 0.005 mg/L.”

Marian (Queensland) – Chloride

2016/17: Marian (Queensland)  Chlorides 301.95mg/L (max), 29.77mg/L (av.)

“Chloride is present in natural waters from the dissolution of salt deposits, and contamination from effluent disposal. Sodium chloride is widely used in the production of industrial chemicals such as caustic soda, chlorine, and sodium chlorite and hypochlorite. Potassium chloride is used in the production of fertilisers.

The taste threshold of chloride in water is dependent on the associated cation but is in the range 200–300 mg/L. The chloride content of water can affect corrosion of pipes and fittings. It can also affect the solubility of metal ions.

In surface water, the concentration of chloride is usually less than 100 mg/L and frequently below 10 mg/L. Groundwater can have higher concentrations, particularly if there is salt water intrusion.

Based on aesthetic considerations, the chloride concentration in drinking water should not exceed 250 mg/L.

No health-based guideline value is proposed for chloride.” 2011 Australian Drinking Water Guidelines

Mackay (Qld) – Turbidity

2020/21: Marian Reticulation (Qld) Turbidity 10.5NTU (max), 0.3NTU (mean)

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.

Marian (Qld) – Iron

2020/21: Marian Reticulation (Qld) Iron 0.4518mg/L (max), 0.0117mg/L (mean)

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

23/3/22: Marian (Queensland) – Nickel

A nickel result above the ADWG health guideline value was detected during routine sampling from Mirani 2 – Patricia Court sample point. On the same day, a compliant result was recorded from Mirani 1 – Alice St, suggesting that the breach was localised. Inspection of the Mirani 2 – Patricia Court sample point and sampling procedures did not identify any cause. No immediate action was taken as the Alice St samples from the same day did not indicate any water quality issues. Resampling was carried out on the 29 March 2022 at Patricia Court and Alice Street, returning compliant results. No further action was taken.

Nickel: ADWG Health Guideline 0.02mg/L. A chemical element and silvery white corrosion resistant metal with a golden tinge. 60% of nickel production is used in nickel steel (particularly stainless steel). In water, mainly a problem with nickel plated fittings. Main releases to the environment are from the burning of fossil fuels and in waste discharges from electroplating industries.

2022/23: Marian Water Treatment Plant (Queensland) Poly Aromatic Hydrocarbons

2022/23:  Levels not specified. “During the 2022-23 financial year, Anthracene, Fluoranthene and Phenanthrene were detected in treated water at Mariann WTP”. Mackay Drinking Water Quality Management Plan 2022/23

The polycyclic aromatic hydrocarbons are a large group of organic compounds with two or more fused aromatic rings. Several hundred have been identified in air, emitted from various combustion and
pyrolysis sources. The principal PAHs include phenanthrene, fluoranthene, pyrene, anthracene, benzo(a) pyrene, benzofluoranthene, chrysene, anthanthrene and naphthalene. PAHs are widespread throughout the environment. They are formed in forest fires and in the combustion
of fossil fuels, and are present in emissions from coke ovens, aluminium smelters and motor vehicles.
Contamination of drinking water can occur by direct atmospheric deposition and by leaching from bituminous liners in water distribution systems.

Marian (Queensland) – Selenium

2013/14: Marian Selenium 0.0043mg/L (max), 0.003mg/L (av.)

Based on health considerations, the concentration of selenium in drinking water should not exceed 0.004 mg/L (2011-2025 guideline 0.01mg/L). “General description Selenium (Se) and selenium salts are widespread in the environment. Selenium is released from natural and human-made sources (such as the burning of coal). Selenium is also a by-product of the processing of sulfide ores, chiefly in the copper refining industry. The major use of selenium is in the manufacture of electronic components. It is used in several other industries, and selenium compounds are used in some insecticides, in hair shampoos as an antidandruff agent, and as a nutritional feed additive for poultry and livestock. Selenium copper alloys have also been identified as a potential replacement for lead copper alloys in plumbing products. Further information on lead replacements in plumbing products (such as selenium copper alloys) is available in Information Sheet 4.1 – Metal and metalloid chemicals leaching from plumbing products. Selenium concentrations in drinking water source waters are generally very low and depend on local geochemistry, climatic conditions (e.g. drought), pH and the presence of iron salts. Selenium in water is mainly present as inorganic compounds, predominantly selenate. Weathering of rocks and soil may result in low levels of selenium in water, which may be taken up by plants (SLR 2022). Food is the major source of intake for Australians. Cereal and grain products contribute most to intake, while fish and liver contain the highest selenium concentrations.” ADWG 2025

2016/23 – Marian (Queensland) – Cyanobacteria, Lead, Chloride, Turbidity, Iron, Nickel, PAH’s, Selenium

in , , ,
October 2020 + October 2021 – Marian WTP Cyanobacteria Concentrations of blue-green algae (cyanobacteria total cells) for FY 2021 – 2022 are graphed in Figure 3 – 2.  Cyanobacteria total cell results for Nebo Rd WTP Raw River Water were generally less than 1000 cells/mL (similar to those for FY 2020 – 2021 and FY 2019 – 2020), except for May 2022 where there was a small increase to 1947 cells/mL. The results did not indicate blue-green algae blooms occurred at Dumbleton Weir. Cyanobacteria total cell results for Marian WTP Raw Water indicate there was a significant bloom in October 2021, with results reaching 689,423 cells/mL. A bloom also occurred in October of the previous year 2016/2018 – Marian (Queensland) – Lead 2013/2014: Marian Lead 0.0082mg/L (max), 0.003mg/L (av.) 2014/2015: Marian Lead 0.008mg/L (max), <0.003mg/kg (av.) 2016/2017: Miriani 1 Alice Street Marian Lead 0.04417mg/L (max), 0.0012mg/L (mean) 2016/2017: Miriani 2 Patricia CCT Marian Lead 0.01262mg/L (max), 0.00158mg/L (mean) 2017/2018: Marian Lead 0.00972mg/L (max), 0.00191mg/L (av.) Patricia Cct A concentration of 0.0126 mg/L for lead was reported for a sample collected from ‘Mirani 2 – Patricia Cct’ on 5 September 2016. This result was initially flagged as exceeding the ADWG health value of 0.01 mg/L and was therefore reported as a drinking water incident. Upon review of this incident it has been identified that this concentration did not in fact exceed the guideline when comparing the result once rounded to a precision level of one significant figure (0.01 mg/L) (as per guidance stipulated in page 165 of the ADWG). Re-analysis of the original sample returned a lead concentration of 0.0085 mg/L. The re-sample results (for a sample collected from Mirani 2 – Patricia Cct on the 12 September 2016) returned a lead result of <0.001 mg/L. Re-analysis results confirmed the original result was not due to analytical error and was unlikely to be due to contamination of the original sub sample at the laboratory. The original and re-analysis results indicate that the sample tap may have deteriorated prior to sample collection and contributed to the high lead result in the sample. No corrective actions were taken as there was deemed to be no risk to public health. Alice Street A concentration of 0.0442 mg/L for lead was reported for a sample collected from the Mirani 1 – Alice Street drinking water sample point on 11 May 2017. This result exceeds the ADWG health value of 0.01 mg/L. Re-analysis of the original sample returned a lead concentration of 0.0415 mg/L. The re-sample results (for a sample collected from the Mirani 1 – Alice Street sample point on the 8 May 2017) returned a lead result of <0.0005 mg/L. Re-analysis results confirmed the ADWG health guideline exceedance. It was expected the original exceedance was the result of tap degradation. Following identification of the exceedance arrangements were made to replace the sample point tap with a brass tap. 2018/19: Marian 0.01255mg/L (max), 0.00106mg/L (av.) May 30 2022: A lead result above the ADWG health guideline values was detected during routine sampling at Mirani 2 – Patricia Court. On the same day, a compliant result was recorded from Mirani 1 – Alice Street, suggesting that the breach was localised. As the sample point is at the end on the line, the reticulation system was flushed and resampling conducted. As the sample tap was only installed in 2021, the result is most likely caused by the tap being unused for extended periods, allowing sedimentation to form in the line, which is then disturbed when the water sample is taken, rather than contamination of the drinking water supply. The sampling procedure for this site now includes a preliminary flush of the main through a 50mm offtake tap prior to sampling. Routine monitoring on the 6 June 2022 and follow up sampling on 10 June 2022 at Patricia Court and Alice Street, returned compliant results. Lead Guideline reduced from 0.01mg/L to 0.005mg/L in June 2025. “The concentration of lead in water within premises may be higher, especially in older buildings, due to contact of the water with lead-containing plumbing products (enHealth 2021). A review found several Australian and international studies that detected up to 0.162 mg/L of lead in drinking water due to leaching from lead-containing plumbing materials including taps and lead service lines, suggesting that leaching of lead from lead-containing plumbing materials can be substantial (SLR 2023)… Based on health considerations, the concentration of lead in drinking water should not exceed 0.005 mg/L.” Marian (Queensland) – Chloride 2016/17: Marian (Queensland)  Chlorides 301.95mg/L (max), 29.77mg/L (av.) “Chloride is present in natural waters from the dissolution of salt deposits, and contamination from effluent disposal. Sodium chloride is widely used in the production of industrial chemicals such as caustic soda, chlorine, and sodium chlorite and hypochlorite. Potassium chloride is used in the production of fertilisers. The taste threshold of chloride in water is dependent on the associated cation but is in the range 200–300 mg/L. The chloride content of water can affect corrosion of pipes and fittings. It can also affect the solubility of metal ions. In surface water, the concentration of chloride is usually less than 100 mg/L and frequently below 10 mg/L. Groundwater can have higher concentrations, particularly if there is salt water intrusion. Based on aesthetic considerations, the chloride concentration in drinking water should not exceed 250 mg/L. No health-based guideline value is proposed for chloride.” 2011 Australian Drinking Water Guidelines Mackay (Qld) – Turbidity 2020/21: Marian Reticulation (Qld) Turbidity 10.5NTU (max), 0.3NTU (mean) 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. Marian (Qld) – Iron 2020/21: Marian Reticulation (Qld) Iron 0.4518mg/L (max), 0.0117mg/L (mean) 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 23/3/22: Marian (Queensland) – Nickel A nickel result above the ADWG health guideline value was detected during routine sampling from Mirani 2 – Patricia Court sample point. On the same day, a compliant result was recorded from Mirani 1 – Alice St, suggesting that the breach was localised. Inspection of the Mirani 2 – Patricia Court sample point and sampling procedures did not identify any cause. No immediate action was taken as the Alice St samples from the same day did not indicate any water quality issues. Resampling was carried out on the 29 March 2022 at Patricia Court and Alice Street, returning compliant results. No further action was taken. Nickel: ADWG Health Guideline 0.02mg/L. A chemical element and silvery white corrosion resistant metal with a golden tinge. 60% of nickel production is used in nickel steel (particularly stainless steel). In water, mainly a problem with nickel plated fittings. Main releases to the environment are from the burning of fossil fuels and in waste discharges from electroplating industries. 2022/23: Marian Water Treatment Plant (Queensland) Poly Aromatic Hydrocarbons 2022/23:  Levels not specified. “During the 2022-23 financial year, Anthracene, Fluoranthene and Phenanthrene were detected in treated water at Mariann WTP”. Mackay Drinking Water Quality Management Plan 2022/23 The polycyclic aromatic hydrocarbons are a large group of organic compounds with two or more fused aromatic rings. Several hundred have been identified in air, emitted from various combustion and pyrolysis sources. The principal PAHs include phenanthrene, fluoranthene, pyrene, anthracene, benzo(a) pyrene, benzofluoranthene, chrysene, anthanthrene and naphthalene. PAHs are widespread throughout the environment. They are formed in forest fires and in the combustion of fossil fuels, and are present in emissions from coke ovens, aluminium smelters and motor vehicles. Contamination of drinking water can occur by direct atmospheric deposition and by leaching from bituminous liners in water distribution systems. Marian (Queensland) – Selenium 2013/14: Marian Selenium 0.0043mg/L (max), 0.003mg/L (av.) Based on health considerations, the concentration of selenium in drinking water should not exceed 0.004 mg/L (2011-2025 guideline 0.01mg/L). “General description Selenium (Se) and selenium salts are widespread in the environment. Selenium is released from natural and human-made sources (such as the burning of coal). Selenium is also a by-product of the processing of sulfide ores, chiefly in the copper refining industry. The major use of selenium is in the manufacture of electronic components. It is used in several other industries, and selenium compounds are used in some insecticides, in hair shampoos as an antidandruff agent, and as a nutritional feed additive for poultry and livestock. Selenium copper alloys have also been identified as a potential replacement for lead copper alloys in plumbing products. Further information on lead replacements in plumbing products (such as selenium copper alloys) is available in Information Sheet 4.1 – Metal and metalloid chemicals leaching from plumbing products. Selenium concentrations in drinking water source waters are generally very low and depend on local geochemistry, climatic conditions (e.g. drought), pH and the presence of iron salts. Selenium in water is mainly present as inorganic compounds, predominantly selenate. Weathering of rocks and soil may result in low levels of selenium in water, which may be taken up by plants (SLR 2022). Food is the major source of intake for Australians. Cereal and grain products contribute most to intake, while fish and liver contain the highest selenium concentrations.” ADWG 2025