From: Moore, Cheryl

Sent: Mon Sep 27 11:23:25 2010

To: waterqualitystandards

Subject: Amendments to Water Quality Standards: Arsenic, Iron, Manganese

Importance: Normal

Reducing the inorganic arsenic criterion to 2.3 ug/L versus the standard set by the Federal regulations of 10 ug/L is excessive and unnecessary.

2.3 ug/L is a level that is difficult for labs to even assess reliably.

Further an increase of “10% or more” is difficult to reliably quantify at these low levels. For instance if a source discharged 5 ug/L the margin of error for the lab test is greater than 10% (0.5 ug/L).

It is not possible to estimate how much the level of arsenic could be reduced through site practices either. Unfortunately the only thing that can reliably demonstrate this effectiveness is sampling.

Please reconsider the actual value of the time and expense this represents to business owners.

Thank you,

Cheryl Moore