2014/15 – Tynong (Victoria) – Lead

Tynong – Victoria – Lead
The high lead result was received as part of non-routine sampling in the Tynong area from a sample taken on 14 May 2015. The sample was being tested for manganese and boron which also included lead as part of the metals suite. This sample was retested on 25 May 2015 and the lead result was confirmed to be 0.015 mg/L (greater than the ADWG limit of 0.01 mg/L). A resample was taken on 26 May 2015 and returned a lead result lower than the detection
levels (<0.001 mg/L). Further to this a nearby sample tap in the zone was tested on 29 May 2015 and returned a lead result of 0.003 mg/L, which is also below the ADWG limit. The additional samples identified that the initial sample was not representative of the water being supplied or a result of system failure. The cause is more likely to be lead leaching from the sample tap fittings.

http://southeastwater.com.au/SiteCollectionDocuments/AboutUs/WaterQualityReport201415.pdf

Based on health considerations, the concentration of lead in drinking water should not
exceed 0.01 mg/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…

Lead can be absorbed by the body through inhalation, ingestion or placental transfer. In adults,
approximately 10% of ingested lead is absorbed but in children this figure can be 4 to 5 times higher. After absorption, the lead is distributed in soft tissue such as the kidney, liver, and bone marrow where it has a biological half-life in adults of less than 40 days, and in skeletal bone where it can persist for 20 to 30 years.

In humans, lead is a cumulative poison that can severely affect the central nervous system. Infants, fetuses and pregnant women are most susceptible. Placental transfer of lead occurs in humans as early as the 12th week of gestation and continues throughout development.

Many epidemiological studies have been carried out on the effects of lead exposure on the intellectual development of children. Although there are some conflicting results, on balance the studies demonstrate that exposure to lead can adversely affect intelligence.

These results are supported by experiments using young primates, where exposure to lead causes significant behavioural and learning difficulties of the same type as those observed in children.

Other adverse effects associated with exposure to high amounts of lead include kidney damage, interference with the production of red blood cells, and interference with the metabolism of calcium needed for bone formation…” ADWG 2011