chrome6.html

From: Book, Steven (DHS-DDWEM)
[<mailto:sbook@dhs.ca.govmailto:sbook@dhs.ca.gov]
Sent: Wednesday, April 18, 2001 10:05 AM
To: Vance, Bill
Cc: Spath, Dave (DHS-DDWEM)
Subject: RE: Chrome-6 analyses by DHS

Bill:

For our investigations, we took samples from wells in Los Banos in Dec 1997 and Mar 1998, from Los Angeles in Oct and Nov 1998, from Daly City and South San Francisco in Jan 2000 and from Davis in Jan 2000, plus a couple of other wells. We also took some surface water samples in Fairfield in Jan 2000.

Here's the summary from our website:

http://www.dhs.ca.gov/ps/ddwem/chemicals/Chromium6/Cr+6index.htm

Ground Water Samples

* In 1997-98, DHS sampled 10 wells in Merced County. Total chromiumwas 18.8-33.5 µg/L, and chromium-6, 16.8-33.0 µg/L (68-100% of total chromium).

* In 1998, DHS sampled three wells in Los Angeles County. Total chromium was 3.4-10.3 µg/L, was chromium-6, ND-5.1 µg/L (<14-54% of total chromium).

* Also in 1998, DHS sampled one well in Contra Costa County. Total chromium was 18.7 µg/L and chromium-6, 1.5 µg/L (8% of total chromium).

* In 1999, a water agency's consultant sampled nine wells in Los Angeles County. Total chromium was 5.3-15 µg/L, and chromium-6, 3.6-11 µg/L (58-100% of total chromium).

* In 2000, DHS sampled eight wells in San Mateo County. Total chromium was 11-28 µg/L, and chromium-6, 7.4-28 µg/L (64-100% of total chromium).

* Also in 2000, DHS sampled three wells in Yolo County. Total chromium was 31-54 µg/L, and chromium-6, 24-35 µg/L (44-97% of total chromium).

Surface Water Samples

* In 2000, DHS took four samples from a source in Solano County. Total chromium was 0.5-8.9 µg/L, and chromium-6 was ND.

Although this preceded the "establishment "of an approved method [EPA method 218.6] as part of our "unregulated chemicals requiring monitoring" regulations, we used that same method (although we used a 0.5-ppb reporting limit, while the approved method has a 1.0 reporting limit). The method includes sampling procedures. Approved laboratories and more information about laboratory analyses are on our website at

http://www.dhs.ca.gov/ps/ddwem/chemicals/Chromium6/Cr+6labs.htm

The analyses were by our laboratory (Sanitation and Radiation Laboratory).We have confidence in the data.

We are posting a summary of the findings of chromium-6 by water systems on our website, at

http://www.dhs.ca.gov/ps/ddwem/chemicals/Chromium6/samplingresults.Htm

http://www.dhs.ca.gov/ps/ddwem/chemicals/Chromium6/samplingresults.htm

.Right now we are updating it monthly.

--Steve

-----Original Message-----

From: Vance, Bill [<mailto:BVance@CALEPA.ca.govmailto:BVance@CALEPA.ca.gov]

Sent: Tuesday, April 17, 2001 5:51 PM

To: Book, Steven (DHS-DDWEM)

Subject: Chrome-6 analyses by DHS

Steve,

Sometime ago, you mentioned to me that Dave Spath had initiated a pilot study to look at chrome-6 concentrations in several locations in California. I know that Davis was one of those locations, and possibly Los Banos in the Central Valley and Daly City in the South Bay were the others. The analyses I am thinking of may have started last year, or perhaps sooner. Because this precedes any formally approved methods for chrome-6, there is a question of who did the analyses, the method(s) used, and the confidence DHS has in the results. Can you shed some light on this? Would be most obliged if you can. Also, do you have a web page that tracks some of the chromate analyses by region (the prevalence issue)?

Regards,

Bill