27/4/22: Mount Bassett Reservoir (Queensland) – Lead

Routine monitoring of the Mount Bassett Reservoir returned a lead result above the ADWG health guideline limit of 0.01 mg/L. Downstream results from Slade Point on the same day return a compliant result for lead, indicating it was a localised incident. Follow-up sampling on 6 May 2022, from two alternative sample points (Emergency Shower at the Reservoir and the top of the reservoir tank) did not record any exceedances. An inspection of the sample tap pipework identified that there was a brass tapping band connected to the off take connection from the water main to the sample tap. The age of this tapping band is unknown. It is believed that the high lead reading is most likely caused by of degradation of the sample tap off take connection. This has been removed and a new off take was established on an
alternative main pipe.

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