NCS000057_Email Correspondence_20111213

Patterson, Robert
From: Patterson, Robert
Sent: Tuesday, December 13, 2011 10:16 AM
To: '[e-mail]'
Subject: NCS000057 - Chemical Specialties, Inc. - Stormwater Permit Renewal
Lonna,
I wanted to follow up from my voice mail I just left for you. I have a couple questions to ask to help with my review of
your renewal application.
1. How and where was the background rainfall sample collected (open area, from roof drain, etc.); and was it just a
single sample?
2. What method is used to determine if the loaded trailer parking area goes to sw or to ww?
Also, we have noted your concerns in your cover letter and we will work with you on addressing those. One thing to
note is that our benchmarks are based on acute toxicity values that are not adjusted for specific sites. These are the
same benchmarks used for any other sites monitoring for Cu and Zn. That said, we recognize that acute values for these
metals are low, and that their toxicity is highly variable and dependant on water hardness. We may consider site -
specific BMPs in lieu of benchmarks for one or more of these parameters. This is something we have done at a few
other facilities.
Thanks.
Robert D. Patterson, PE
Environmental Engineer
NCDENR I DWQ I Stormwater Permitting
1617 Mail Service Center, Raleigh, NC 27699- 1617 '.l.id 1 512 N. Salisbury St, Raleigh, NC 27604 1 91h Floor ion ;,. !'.Ai
[phone] Phone [phone] I,%ix I Robert. Pattersonrrncdenr.t;ov l-moil I http://portal.ncdenr.org/web/wa/ws/su W'cbsor
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