Lead and Water Pipes

[mbkitmgr]

Here in Australia the "proverbial has hit the fan" and a formal health warning has been issued about the contamination of our drinking water due to the presence of lead in our taps/pipes etc.

The Gov have released an advisory that we are to flush the tap for 30 seconds when say getting a glass of water or filling the Jug/Kettle.  Further advice is to run the tape for 2-3 mins if we have been away from our home for a few days before drinking the water.

My Questions - I understand that LEAD is present in the Brass fittings/taps etc but

1. why doesnt it dissipate over time on the surface area of the fittings in contact with water
2. How does it continue to contaminate the water on an ongoing basis if it doesnt dissipate

[John Cuthber]

Some pipes are made of lead.

It can't "dissipate"; if it did there would be no pipe.

[Carrock]

In hard water areas a protective film forms inside the pipes, reducing leaching of lead from the pipes.

With soft water, especially if it is acidic, leaching is significantly greater.

IIRC, reckless changes in water sources in Flint caused a major increase in contamination from pipes as well as from the sources.

The contamination you're exposed to depends on these factors as well as your pipes.

Perhaps a chemist on this site will supply more reliable information.

[studiot]

1 hour ago, mbkitmgr said:

Here in Australia the "proverbial has hit the fan" and a formal health warning has been issued about the contamination of our drinking water due to the presence of lead in our taps/pipes etc.

The Gov have released an advisory that we are to flush the tap for 30 seconds when say getting a glass of water or filling the Jug/Kettle.  Further advice is to run the tape for 2-3 mins if we have been away from our home for a few days before drinking the water.

My Questions - I understand that LEAD is present in the Brass fittings/taps etc but

1. why doesnt it dissipate over time on the surface area of the fittings in contact with water
2. How does it continue to contaminate the water on an ongoing basis if it doesnt dissipate

 

I remember learning about this in one of my very first Chemistry lessons at school.

 

Lead has been used since Roman times for making water conduits since it does not rust away like iron as John said.

However over time softer water, which is can be slightly acid, slowly attacks even lead taking away small quantities.

Lead is a cumulative poison in the human body so this is clearly undesirable and even small quantities are undesirable and add up over time.

 

 

As a result, authorities in the UK, and no doubt elsewhere, are required to maintain the supply of potable (drinkable) water within certain limits.

This is usually measured by hardness rather than the pH acidity scale (We did an experiment using Clark's Standard Soap Solution)
The degree of hardness has other features and implications to as well as acidity so it a wider measure.

Please note there should be no lead in brass taps or other fittings.
Any lead will be from old fashioned soldered joints.
Modern solders are required to be lead free.

Note that lead was also used in paints and electrical solder, both of which have/are now being phased out.

 

Does this help?

[druS]

23 hours ago, mbkitmgr said:

Here in Australia the "proverbial has hit the fan" and a formal health warning has been issued about the contamination of our drinking water due to the presence of lead in our taps/pipes etc.

The Gov have released an advisory that we are to flush the tap for 30 seconds when say getting a glass of water or filling the Jug/Kettle.  Further advice is to run the tape for 2-3 mins if we have been away from our home for a few days before drinking the water.

My Questions - I understand that LEAD is present in the Brass fittings/taps etc but

1. why doesnt it dissipate over time on the surface area of the fittings in contact with water
2. How does it continue to contaminate the water on an ongoing basis if it doesnt dissipate

Hey, mate. I live in Australia and among other things work in hydraulic design in buildings. I haven't heard any of this. Could you expand with reference?

The only thing I can think of is some maybe somewhere like Mt Isa where from recollection there has been led deposits found through the developed areas. I'd love to look into it if you can give me more than "proverbial has hit the fan" as I see nothing around it in the media here.

BTW there should be no lead discharge from brass fittings as there is none in it.

[Carrock]

'australia lead in pipes' provided some references. e.g.

This is from 2016 and may have been more publicised recently

‘Widespread’ lead contamination of domestic tap water found in NSW

Quote

“We were aware that domestic water may be accidentally contaminated through lead use in brass fittings, so to characterise that we wanted to know what the extent of in-house contamination was.”

Lead contamination doesn't seem to be a major problem in NSW.

 

Quote

 

The team tested 212 such ‘first draw’ samples, and found copper in nearly all of them, while lead was present in 56 per cent of the households tested. According to guidelines, drinking water should contain no more than 10 micrograms of lead per litre - but 8% of the lead samples contained higher levels that that.

"The highest concentration sample that I collected in this study was 89 micrograms [of lead] per litre," says Harvey. “The results of this study demonstrate that along with other potential sources of contamination in households, plumbing products that contain up to 2.84 per cent of detectable lead are contributing to contamination of household drinking water.”

 

 

[Phi for All]

!

Moderator Note

Moved from Science Education to Ecology and the Environment.

 

[mbkitmgr]

Wow, thanks to all. 

The federal gov issued the warning via the media a few weeks ago and I was trying to understand the science behind how the lead remains.  One of our Supermarket chains (Aldi) had to recall tapware due to high concentrations of lead.  As far as I know this lead to an investigation and the realisation that lead contamination is an issue across the board.

I just wondered how the lead continues to contaimante the water indefinitely - why doesnt it transfer lead from the pipes to the water and reduce the lead levels in the surface in contact with water - therefore reducting the longterm contamination.