Second Unregulated Contaminant Monitoring Rule
The 1996 Safe Drinking Water Act (SDWA) amendments require that once every five years EPA issue a new list of no more than 30 unregulated contaminants to be monitored by public water systems (PWSs).
The second Unregulated Contaminant Monitoring Rule (UCMR 2) was published on January 4, 2007. UCMR 2 required monitoring for 25 contaminants between 2008 and 2010 using analytical methods developed by EPA, consensus organizations, or both. This monitoring provides a basis for future regulatory actions to protect public health.
- Federal Register Notice: Revisions to the UCMR 2 for Public Water Systems, January 4, 2007
- UCMR 2 Basic Information Fact Sheet (PDF)(2 pp, 9.5 K, About PDF)
UCMR 2 contaminants and analytical methods
Assessment Monitoring (List 1 contaminants)
All PWSs serving more than 10,000 people and 800 representative PWSs serving 10,000 or fewer people were required to monitor for 10 List 1 contaminants during a 12-month period from January 2008 through December 2010.
Two Insecticides
|
Contaminant |
CAS Registry Number1 |
Minimum Reporting Level |
Sampling Points2 |
Analytical Methods |
|---|---|---|---|---|
|
Dimethoate |
60-51-5 |
0.7 µg/L |
EPTDS |
EPA 527 |
|
Terbufos sulfone |
56070-16-7 |
0.4 µg/L |
EPTDS |
EPA 527 |
Five Flame Retardants
|
Contaminant |
CAS Registry Number1 |
Minimum Reporting Level |
Sampling Points2 |
Analytical Methods |
|---|---|---|---|---|
|
2,2',4,4'-tetrabromodiphenyl ether (BDE-47) |
5436-43-1 |
0.3 µg/L |
EPTDS |
EPA 527 |
|
2,2',4,4',5-pentabromodiphenyl ether (BDE-99) |
60348-60-9 |
0.9 µg/L |
EPTDS |
EPA 527 |
|
2,2',4,4',5,5'-hexabromobiphenyl (HBB) |
59080-40-9 |
0.7 µg/L |
EPTDS |
EPA 527 |
|
2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153) |
68631-49-2 |
0.8 µg/L |
EPTDS |
EPA 527 |
|
2,2',4,4',6-pentabromodiphenyl ether (BDE-100) |
189084-64-8 |
0.5 µg/L |
EPTDS |
EPA 527 |
Three Explosives
|
Contaminant |
CAS Registry Number1 |
Minimum Reporting Level |
Sampling Points2 |
Analytical Methods |
|---|---|---|---|---|
|
1,3-dinitrobenzene |
99-65-0 |
0.8 µg/L |
EPTDS |
EPA 529 |
|
2,4,6-trinitrotoluene (TNT) |
118-96-7 |
0.8 µg/L |
EPTDS |
EPA 529 |
|
Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) |
121-82-4 |
1 µg/L |
EPTDS |
EPA 529 |
Screening Survey (List 2 contaminants)
All PWSs serving more than 100,000 people, 320 representative PWSs serving 10,001 to 100,000 people, and 480 representative PWSs serving 10,000 or fewer people were required to monitor for 15 List 2 contaminants during a 12-month period from January 2008 through December 2010.
Three Parent Acetanilides
|
Contaminant |
CAS Registry Number1 |
Minimum Reporting Level |
Sampling Points2 |
Analytical Methods |
|---|---|---|---|---|
|
Acetochlor |
34256-82-1 |
2 µg/L |
EPTDS |
EPA 525.2 |
|
Alachlor |
15972-60-8 |
2 µg/L |
EPTDS |
EPA 525.2 |
|
Metolachlor |
51218-45-2 |
1 µg/L |
EPTDS |
EPA 525.2 |
Six Acetanilide Degradates
|
Contaminant |
CAS Registry Number1 |
Minimum Reporting Level |
Sampling Points2 |
Analytical Methods |
|---|---|---|---|---|
|
Acetochlor ethane sulfonic acid (ESA) |
187022-11-3 |
1 µg/L |
EPTDS |
EPA 535 |
|
Acetochlor oxanilic acid (OA) |
184992-44-4 |
2 µg/L |
EPTDS |
EPA 535 |
|
Alachlor ethane sulfonic acid (ESA) |
142363-53-9 |
1 µg/L |
EPTDS |
EPA 535 |
|
Alachlor oxanilic acid (OA) |
171262-17-2 |
2 µg/L |
EPTDS |
EPA 535 |
|
Metolachlor ethane sulfonic acid (ESA) |
171118-09-5 |
1 µg/L |
EPTDS |
EPA 535 |
|
Metolachlor oxanilic acid (OA) |
152019-73-3 |
2 µg/L |
EPTDS |
EPA 535 |
Six Nitrosamines
|
Contaminant |
CAS Registry Number1 |
Minimum Reporting Level |
Sampling Points2 |
Analytical Methods |
|---|---|---|---|---|
|
N-nitroso-diethylamine (NDEA) |
55-18-5 |
0.005 µg/L |
EPTDS & DSMRT |
EPA 521 |
|
N-nitroso-dimethylamine (NDMA) |
62-75-9 |
0.002 µg/L |
EPTDS & DSMRT |
EPA 521 |
|
N-nitroso-di-n-butylamine (NDBA) |
924-16-3 |
0.004 µg/L |
EPTDS & DSMRT |
EPA 521 |
|
N-nitroso-di-n-propylamine (NDPA) |
621-64-7 |
0.007 µg/L |
EPTDS & DSMRT |
EPA 521 |
|
N-nitroso-methylethylamine (NMEA) |
10595-95-6 |
0.003 µg/L |
EPTDS & DSMRT |
EPA 521 |
|
N-nitroso-pyrrolidine (NPYR) |
930-55-2 |
0.002 µg/L |
EPTDS & DSMRT |
EPA 521 |
Notes
- Chemical Abstract Service (CAS) Registry Number
- Sample point:
- Entry points to the distribution system (EPTDS)
- Distribution system maximum residence time (DSMRT)