"Leaching of Arsenic from Dezincification Resistant Brass"
"As I understand it, Arsenic is added to copper alloys containing 25-37% zinc to provide adequate dezincification resistance to maintain physical properties, particularly in potable water application. Are there any problems with Arsenic leaching from the brass? Similar issues have arisen in respect of lead over the past few years, leading to changes in the some of the alloys used in the manufacture of plumbing fittings."
I am not aware of any issues regarding leaching of arsenic from Admiralty brass alloys. I am aware of the EPA restrictions regarding maximum allowable lead content in copper alloys for potable water service. However, the permissible lead content is much greater than the amount of arsenic added to Admiralty. After further thought, if you look at the numbers, the typical DZR brass contains of the order of 0.1% arsenic. A typical fitting weighs around 300g, in which case there is about 0.3g of arsenic in the total fitting. All of the arsenic would need to corrode into a remarkably small quantity of water (6000L) to reach the potable water limit of 0.05mg/L set by WHO assuming zero background levels. This represents about a week's water consumption by a typical household. Given that such fittings actually last for many years in typical application, it is simply not possible to get significant arsenic contamination of the water.
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