Controversy on additive to prevent lead poisoning

Jamie Hall

before I saw the light and became a building supervisor/maintainer (much more fun!) I was (still am...) a registered PE who happened to specialise in water treatment problems, so... my two cents worth:

First, I know of no studies which suggest that fluoride, in appropriate concentrations, (which are low, and water chemistry dependent) is harmful. Lack of it most assuredly is, as an honest dentist will tell you.

Second, zinc orthophosphate is not harmful; the zinc levels involved are very low and pose no threat to most wastewater treatment plants (not all; I know of one exception, but that was a situation where there was a fairly heavy zinc load already from an industry, and they were hitting EPA discharge limits). The plus side is that it is great from the standpoint of corrosion control -- which is what we are talking about here. It definetly reduces corrosion in copper pipes but, more important, it really reduces the corrosion of old lead pipes and lead solder, which in turn reduces the lead concentration in the resulting water. I'd probably recommend adding the stuff.

As to 'run the tap for 1 minute to flush the lines'? Oh please. I have run many chemical analyses on water from taps, and I have yet to get stable results from less than a five minute flush at full volume -- in other words, at least 10 gallons of water. Even then, depending on the exact plumbing in the building, and the street connection, that may not be enough. In other words, don't bet your kid's mind on a one minute flush...

D107

Some would rather let faucet run a few minutes than use additive

I thought a few Wallies might have ideas on how to approach this municipal issue.

Our town in Westchester has been debating the installation of zinc orthophosphate in the water system.

The Village has conducted tests which indicate that homes with older plumbing have lead levels that are nearing the 'action level'.

Our water comes from large municipal wells and for years they have had to flush the entire system bi-annually to get rid of brown sediment some of it caused by corrosion. Some of this has been alleviated by replacing old water mains, but the problem remains. A few surrounding communities already use the chemical and much evidence has been presented indicating no ill effects. Some have questions about a potential overconcentration of zinc.

A concern has been expressed about the chemical causing a reduction of calcium in humans leading to reduction of bone density. Of course our water is not a great source of calcium anyway and I haven't seen evidence that such a chemical would reduce the body's ability to absorb whatever calcium IS in the water.

Three other concerns have been raised by officials:

1- Would the coating of the chemical inhibit the anti-bacterial action of copper plumbing;

2-Would the zinc precipitate out of water and build up inside pipes, possibly resulting in a hazardous level of zinc when someone turns on the tap.

3- Would the zinc, which would obviousy end up in the sewage system, affect the ability of the county to treat the Village sewage?

The Village has discussed new mixing equipment to better blend warmer and colder water in the village storage tank during summer months to improve water quality.

Some have pointed out that the town's decision years ago to forego fluoride in the water system was proven correct in the light of the latest evidence. They recommend that rather than add a potentially harmful substance to the water supply, that homeowners simply take precautions by running faucets a minute or so before use to clear lead or other contaminants from the line.

There seems to be two issues here: one is lead buildup in homes and the other is corrosion in the mains, both of which could be benefited by the additive.

Thanks for any thoughts,

David

Dave_4

Given the water crisis and drought potential...

in most of the country, has anyone done the rather simple math of:

1) How many people in the community?

2) How many times a day each resident uses a faucet to draw water - both hot and/or cold?

3) The gallons per second each draw consumes?

4) The calculation of how much water will overload the already marginal sewer treatment plant with that 1 minute "flush" times a few million an hour?

5) The impact on the resvoir/well draw resulting from the added demand of "purging"?

Finally, I don't think politicians should be debating municpal water chemistry - unless qualified, e.g., chemical engineers, water quality consultants with heavy credentials in appropriate schooling and/or degrees.

Politicians should search for experts and examine the supporting data experts might offer. I'm sure Westchester County has plenty of "in-house" experts. Is that where the confusion comes from? If so, welcome to American politics. Little to do with science, lots to do with posturing...

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D107

Ken you nailed it

Your questions are precisely the ones I wanted to see--wallies can be so clearly analytical in so many fields. Yes, I'm sure posturing enters into this all the time. 7000 residents here. I would add two questions to yours:

1-How many residents will actually do the one-minute flush when it comes down to it?

2-Has it been proven that fluorination is/was a bad thing?

It usually comes down to which course of action is the lesser of two evils.

Thanks,

David

Dave_4

I can see...

you are well aware of the game.

Unless there is no sewer or water consumption taxes in your town, no one will purge a faucet - for any reason. If the watr is truly free, asume 5% may wait 10 seconds, zero the full half minute the typical plumbing system would require to "clear the lines."

I have a neighbor who spouts the anti-flouride mantra. She has nice teeth, is a wannabe vegan and just bought a wood stove and smokes cigarettes on occassion. The wood stove will release more toxins in an hour than my boiler in a year. One of her Marlboro Lights does more harm to her body than all the flouride she's ingested over her lifetime.

The lesser of two evils is an excellent means to choose between available options. But it provides great grist for the political mill of Westchester, or just about any town on earth...

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