2015/17 – Chillagoe (Queensland) – Lead, Arsenic

2015/17 – Chillagoe (Queensland) – Lead

2015/16 – Chillagoe (Queensland) – Lead 0.023ug/L (max – treated), av., 0.007ug/L

A treated water sample sourced from a tap immediately downstream of the Chillagoe Water Filtration Plant 2 Mar 2016, was found to have Lead in excess of the ADWG safe drinking level. The incident was reported** to the Regulator immediately upon MSC staff being notified by the Cairns Regional Council laboratory. As the raw water samples (taken on the same day) had negligible Lead concentrations, it was believed that the sample was an anomaly. Subsequent follow-up test results had trace amounts of lead present (0.002, <0.001 & 0.001 mg/L). The lead had not been previously found in significant concentrations in the Chillagoe drinking water supply and hasn’t been found in significant concentrations since.

The previously described Chillagoe Lead incident was reported to the Regulator Mar 2016 and was given the incident number DWI-7-557-00002. No action was taken after the incident was investigated and found to be an anomaly. There were no other incidents or events associated with the MSC potable water supplies reported to the regulator

Mareeba Shire – Annual Drinking Water Quality Management Plan 2015/16

2016/17 – Chillagoe (Queensland) – Lead 0.053ug/L (max – treated), av., 0.01575ug/L

A treated water sample, sourced from a tap immediately downstream of the Chillagoe Water Filtration Plant 8 Mar 2017, was found to have Lead in excess of the ADWG safe drinking level. The incident was reported** to the Regulator immediately upon MSC staff being notified by the Cairns Regional Council laboratory. As the raw water samples (taken on the same day) had negligible Lead concentrations (Bore1 0.003 mg/L & Bore3 0.002 mg/L) it was believed that the sample was an anomaly. A subsequent follow up test results had a trace amount of lead present (0.002 mg/L). Monthly tests for lead in the raw, backwash and treated water are currently being conducted with no exceedances in the treated water to date.

Mareeba Shire – Annual Drinking Water Quality Management Plan 2016/17

Lead Australian Drinking Water Guideline 0.01mg/L

“… Lead can be present in drinking water as a result of dissolution from natural sources, or from household plumbing systems containing lead. These may include lead in pipes, or in solder used to seal joints. The amount of lead dissolved will depend on a number of factors including pH, water hardness and the standing time of the water.

Lead is the most common of the heavy metals and is mined widely throughout the world. It is used in the production of lead acid batteries, solder, alloys, cable sheathing, paint pigments, rust inhibitors, ammunition, glazes and plastic stabilisers. The organo-lead compounds tetramethyl and tetraethyl lead are used extensively as anti-knock and lubricating compounds in gasoline…ADWG 2011

2017 March – Chillagoe (Queensland) – Arsenic

2015/16 – Chillagoe (Queensland) – Arsenic 0.012ug/L (max – untreated), av., 0.008ug/L (untreated)

2017 March – Chillagoe (Queensland) – Arsenic 0.012ug/L (untreated), av, 0.0105ug/L (untreated)

In the evening of Monday 8 August 2016 the gas injection system of the Chillagoe Water Treatment Plant faulted and shut down which in turn shut down the Arsenic Treatment Plant. MSC Water Officers investigated the following morning and notified management 1 pm Tuesday 9 August after determining that there was not going to be an immediate resolution. The WSR was notified at 1:07 PM Tuesday 9 August 2016 and a report submitted††.

Arsenic: Australian Drinking Water Guideline = 0.01mg/L

Arsenic is bioaccumulative and symptoms may take 10-15 years to develop after expsoure at high levels. Drinking water can be contaminated with inorganic arsenic through wind blown dust, leaching or runoff from soil, rocks and sediment. Groundwater sources such as bores will usually have higher arsenic levels than surface water. In major Australian reticulated water supplies concentrations of arsenic range up to 0.015mg/L, with typical values less than
0.005mg/L. http://www.health.qld.gov.au/ph/documents/ehu/2676.pdf