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Unregulated Chemicals Requiring Monitoring

Last Update: May 18, 2010

The regulations for unregulated chemicals requiring monitoring were repealed (PDF)Opens in new window., effective October 18, 2007.  Perchlorate, one of these chemicals, is now a regulated contaminant.

The requirements for this monitoring (PDF)Opens in new window.(Title 22 of the California Code of Regulations §64450) became effective January 3, 2001.  Monitoring for chromium-6 was to have been completed by December 31, 2002, and for other chemicals, by December 31, 2003. 

For an overview of the results of this monitoring, click here.

For additional information, particularly for chromium-6, see Guidance for Unregulated Chemicals Requiring Monitoring (PDF)Opens in new window.(also see Notes, below). Also, see  Proposed Alternate Sample Preservation Buffer for Hexavalent Chromium (PDF)Opens new browser window.- May 18, 2010. 

Unregulated Chemicals Requiring Monitoring 
(22 CCR §64450, repealed October 18, 2007)
Chemical Method DLR*
Boron 200.7 & 200.8 100
Chromium-6 218.6 1
Dichlorodifluromethane 524.2 & 502.2 0.5
Ethyl tertiary butyl ether 524.2 & 502.2 3
Perchlorate 314 4
Tertiary amyl methyl ether 524.2 & 502.2 3
Tertiary butyl alcohol 524.2 2
1,2,3-Trichloropropane --** 0.005
Vanadium 200.8 & 200.9 3

*DLR = Detection limit for purposes of reporting, in micrograms per liter (µg/L)
**Methods for 1,2,3-TCP are Continuous Liquid-Liquid Extraction (PDF)Opens in new window.- Gas Chromatography / Mass Spectrometry (GC/MS) and Purge and Trap (PDF)Opens in new window.- GC/MS [see Analysis for 1,2,3-TCP]

  • NOTE 1:  The Department extended §64450(b)'s "vulnerable time" to enable collection of one of the two required groundwater samples between May 1 and September 30.
  • NOTE 2:  These regulations' adoption occurred before the availability of a method capable of achieving 1,2,3-TCP's DLR of 0.005 µg/L.  Some utilities proceeded with monitoring, using laboratory analyses with higher DLRs.  Unfortunately, findings of non-detect (ND) with a DLR higher than 0.005 µg/L do not provide the Department with adequate information needed for possible standard setting.  The Sanitation and Radiation Laboratory developed an adequate method and some commercial laboratories are able to achieve the 0.005-µg/L DLR with either EPA method 504.1 or 551.1. Therefore, any utility with 1,2,3-TCP findings of ND with reporting levels of 0.010 µg/L or higher should perform follow-up sampling of representative sources for analysis using a method with a 0.005-µg/L DLR.   [see Analysis for 1,2,3-TCP for more information]

Last modified on: 8/19/2013 1:24 PM