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UCMR Monitoring Results

Last Update: April 11, 2005

Unregulated Chemicals for which Monitoring is Required

CDPH has a regulation that identifies nine chemicals as unregulated contaminants for which monitoring is required (UCMR).  Methods and detection limits for purposes of reporting (DLRs) are presented here.  This monitoring was to have been completed by 2003.  

The monitoring results from the UCMR process can be used by CDPH for cost estimates for monitoring and treatment, as part of the MCL process, should an MCL be considered appropriate.  

CDPH intends to establish MCLs for three of the UCMR chemicals. It is in the process of developing an MCL for perchlorate, and will be developing an MCL for chromium-6, once a public health goal (PHG) is available.  CDPH has requested a PHG for 1,2,3-trichloropropane (1,2,3-TCP).  (Find out more about PHGs here.)

Findings

Results from UCMR sampling that occurred from 2000 through 2004, as compiled in April 2005,  are presented in Tables 1, 2, and 3.  Distribution by county is presented for the five organic chemicals (Table 2) and the four inorganics (Table 3):

There are ~16,000 drinking water sources, though not all are subject to UCMR requirements.  

Table 1. Results of  UCMR analyses (2000-2004)

.

No. of Sources

UCMR Chemical

 Detects Detects >NL*
Boron 3,797** 152
Chromium-6 3,482** --***
Dichlorodifluoromethane (Freon 12) 180 0
Ethyl tertiary butyl ether (ETBE) 2 --
Perchlorate   462 275
Tertiary amyl methyl ether (TAME) 0 --
Tertiary butyl alcohol (TBA) 46 12
1,2,3-TCP 405 388
Vanadium 5,483** 146

*NL=Notification level, discussed below
**The large number of detections reflects the natural occurrence of the chemical.
***Chemical has no notification level.

Findings by county are presented in Tables 2 and 3.  Some chemicals were detected above their notification levels. Notification of local agencies by water systems would be required if subsequent sampling confirmed those levels. (Note that the values presented in Tables 1, 2 and 3, are not based on confirmed findings, only single detections.)

Table 2.  Drinking water sources with organic UCMR detections 2000-2004, and detections above notification levels (NLs)* 

County Freon 12 ETBE TAME TBA 1,2,3-TCP
. No. of 
Sources
No.
>NL
No. of Sources No. of Sources No. of 
Sources
No.
>NL
No of Sources No. 
>NL
Alameda 5 . . . 1 . 1 1
Amador . . . . 1 1 . .
Calaveras . . . . 1 1 . .
El Dorado . . . . 1 . . .
Fresno 33 . . . . . 72 68
Kern 4 . . . 15 7 111 108
Kings . . . . . . 1 1
Los Angeles 65 . 1 . 4 . 48 43
Madera . . . . 1 . 3 3
Merced . . . . 1 . 28 28
Monterey 3 . . . 1 . 5 3
Orange 4 1 1 2 2
Riverside . . . . . . 18 17
Sacramento 5 . . . 2 1 2 2
San Benito . . . . . . 1 1
San Bernardino 43 . . . 4 . 28 27
San Diego . . . . 7 . 6 6
San Joaquin 3 . . . 1 . 14 14
San Luis Obispo . . . . 1 . 3 2
San Mateo . . . . . . 7 7
Santa Barbara . . . . . . 1 1
Santa Clara 5 . 1 . . . . .
Santa Cruz . . . . 2 . 2 2
Shasta . . . . 2 1
Solano . . . . . . 2 2
Stanislaus 9 . . . . . 12 12
Sutter . . . . . . 3 3
Tulare 4 . . . . . 34 33
Yolo 1 . . . . . . .
Yuba . . . . 1 . 1 1
TOTAL 180 0 2 0 46 12 405 388
DLR (mg/L) 0.0005 . 0.002 0.002 0.003 . 0.000005 .
NL (mg/L) . 1 n/a** n/a** . 0.012 . 0.000005
*Number of drinking water sources with at least one detection in water sampled 2000-2004.  Numbers are considered "draft" because they will change with subsequent updates.
** ETBE and TAME do not have NLs. 

 

Table 3.  Drinking water sources with inorganic UCMR  detections 2000-2004, and detections above notification levels (NLs)*  
County Boron  Cr-6** Perchlorate Vanadium 
. No. of 
Sources
No.
>NL
No. of 
Sources
No. of 
Sources
No.
>NL
No. of 
Sources
No.
>NL
Alameda 43 . 34 . . 28 .
Alpine 1 . . . . . .
Amador 10 . 4 . . 6 .
Butte 38 2 61 . . 97 .
Calaveras 6 1 1 . . 7 .
Colusa 6 . 4 . . 1 .
Contra Costa 42 15 5 . . 13 .
Del Norte . . 6 . . . .
El Dorado 5 . 3 . . 18 .
Fresno 33 3 341 1 . 412 7
Glenn 15 . 21 . . 17 .
Humboldt 10 . 10 . . 4 .
Imperial 10 . 2 3 . 10 2
Inyo  13 3 4 . . 35 .
Kern 386 14 193 5 3 328 7
Kings 37 . 2 3 1 13 1
Lake 51 12 8 . . 26 .
Lassen 14 . 1 . . 27 .
Los Angeles 702 12 489 147 99 635 5
Madera 12 . 30 . . 51 .
Marin 6 . . 1 1 4 1
Mariposa 6 . 2 . . 8 .
Mendocino 55 3 8 1 . 12 .
Merced 27 1 73 2 2 88 .
Modoc 6 . 1 . . 10 .
Mono 4 . 1 . . 7 .
Monterey 90 1 135 10 7 146 .
Napa 28 . 1 . . 24 .
Nevada 9 . 8 1 1 21 .
Orange 188 . 5 37 7 170 .
Placer 9 . 11 . . 20 .
Plumas 1 . . . . 16 .
Riverside 169 11 285 93 60 426 21
Sacramento 82 1 300 12 6 309 .
San Benito 58 8 22 2 1 41 .
San Bernardino 232 7 454 93 60 706 53
San Diego 74 . 5 6 1 110 2
San Francisco 3 . . . . 1 .
San Joaquin 150 12 185 18 11 316 7
San Luis Obispo 170 1 94 . . 227 2
San Mateo 15 . 15 . . 18 .
Santa Barbara 138 1 40 . . 114 5
Santa Clara 174 3 107* 12 5 157 .
Santa Cruz 37 1 15 . . 19 .
Shasta 18 1 12 . . 99 .
Sierra . . . . . 9 .
Siskiyou 5 . . . . 19 1
Solano 74 . 31 . . 73 .
Sonoma 156 8 30 2 1 99 .
Stanislaus 98 3 157 . . 231 10
Sutter 18 . 21 . . 16 .
Tehama 6 . 42 . . 28 .
Trinity 1 . 1 . . 4 .
Tulare 27 . 130 11 7 249 18
Tuolumne 3 . . . . 10 .
Ventura 150 5 11 2 2 71 4
Yolo 81 23 54 . . 57 .
Yuba 8 . 9 . . 20 .
TOTAL 3,797 152 3,482 462 275 5,483 146
DLR (mg/L) 0.1 . 0.001 0.004 . .003 .
NL (mg/L) . 1 n/a** . 0.006 . 0.05
*Number of drinking water sources with at least one detection in water sampled 2000-2004.  Numbers are considered "draft" because they will change with subsequent updates.
**Chromium-6 has no NL.  It is regulated under the total chromium MCL of 0.05 mg/L.  Five sources had Cr-6 detected above 0.05 mg/L.

 

 
 
Last modified on: 6/12/2008 2:12 PM