Negatives on anti-corrosive Zinc Orthophosphate in water?

D107

I thought a few Wallies might have some knowledge of this:

Our village in Westchester will likely soon install zinc orthophosphate in the water system. They are currently on hold until research is completed to verify there are no negatives.

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. 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 zing 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.

As for heating, websites promoting the chemical show photos of corroded heating equipment arising from NOT having this chemical.

Any thoughts?

Thanks,

David