Water: Six-Year Review 2 of Drinking Water Standards
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In March 2010, the Agency announced the review results for the Agency’s second Six-Year Review (called Six-Year Review 2). After performing a detailed review of 71 National Primary Drinking Water Regulations (NPDWRs), the Agency believes that 67 NPDWRs remain appropriate (i.e., do not need to be revised) and four NPDWRs are candidates for regulatory revision. These four NPDWRs include acrylamide, epichlorohydrin, tetrachloroethylene, and trichloroethylene. In addition to the 71 NPDWRs reviewed in detail for the Six-Year Review 2, 14 other NPDWRs were included in the review but did not need a detailed review because of recent or ongoing regulatory actions (i.e., DBPs, lead and copper, and microbials).
Announcement of the Completion of EPA's Second Review of Existing Drinking Water Standards
- Federal Register Notice (Extension)
National Primary Drinking Water Regulations; Announcement of the Results of EPA's Review of Existing Drinking Water Standards and Request for Public Comment and/or Information on Related Issues; Extension of the Comment Period
June 1, 2010: (Volume 75, Number 104)
HTML Version | PDF Version (2pp, 51K) - Federal Register Notice
National Primary Drinking Water Regulations; Announcement of the Results of EPA's Review of Existing Drinking Water Standards and Request for Public Comment and/or Information on Related Issues; Notice
March 29, 2010: (Volume 75, Number 59)
HTML Version | PDF Version (74pp, 1M) - Fact Sheet PDF (5pp, 41K)
You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.
- Summary Table of Six-Year Review 2 Results
- Support Documents for EPA’s Second Review of Existing Drinking Water Standards
Available in the docket for this FR notice (Docket ID: EPA-HQ-OW-2008-0747)
- EPA Protocol for the Second Review of Existing National Primary Drinking Water Regulations (Updated) PDF (37pp, 410K)
October 2009 EPA 815-B-09-002 - Analytical Feasibility Support Document for the Second Six-Year Review of Existing National Primary Drinking Water Regulations PDF (213pp, 1M)
October 2009 EPA 815-B-09-003 - Occurrence Analysis for Potential Source Waters for the Second Six-Year Review of National Primary Drinking Water Regulations (51pp, 2M)
October 2009 EPA 815-B-09-004 - Development of Estimated Quantitation Levels for the Second Six-Year Review of National Primary Drinking Water Regulations PDF (56pp, 674K)
October 2009 EPA 815-B-09-005
- November 2010 – A corrected data set for nitrate monitoring data has been posted. Under further review of a state data set a coding inconsistency was identified. This inconsistency has been rectified and corrected data plus analysis outcomes have been posted.
- The Analysis of Regulated Contaminant Occurrence Data from Public Water Systems in Support of the Second Six-Year Review of National Primary Drinking Water Regulations PDF (519pp, 9M)
Revised September 2010 EPA 815-B-09-006
- Water Treatment Technology Feasibility Support Document for Chemical Contaminants for the Second Six-Year Review of National Primary Drinking Water Regulations PDF (34pp, 346K)
October 2009 EPA 815-B-09-007 - Consideration of Other Regulatory Revisions in Support of the Second Six-Year Review of the National Primary Drinking Water Regulations PDF (30pp, 233K)
October 2009 EPA 815-B-09-008 - Six-Year Review 2 Health Effects Assessment: Summary Report PDF (174pp, 932K)
October 2009 EPA 822-R-09-006 - Additional Support Documents (Detailed occurrence analyses not referenced in the Federal Register Notice)
- Contaminant Occurrence Support Document for Category 1 Contaminants for the Second Six-Year Review of National Primary Drinking Water Regulations PDF
(311pp, 8M)
October 2009 EPA 815-B-09-010 - Contaminant Occurrence Support Document for Category 2 Contaminants for the Second Six-Year Review of National Primary Drinking Water Regulations PDF (374pp, 13M)
October 2009 EPA 815-B-09-011
- Contaminant Occurrence Support Document for Category 1 Contaminants for the Second Six-Year Review of National Primary Drinking Water Regulations PDF
Summary of Six-Year Review 2 Results
The following table provides a summary of the Six-Year Review 2 results for each of the 71 NPDWRs that were reviewed in detail as part of the Six-Year Review 2 effort.
| Summary of Review outcomes | Contaminants | |||
|---|---|---|---|---|
| Recent or Ongoing Action (14 NPDWRs) | Bromate Chloramines Chlorine Chlorine dioxide Chlorite Coliform Copper |
Cryptosporidium Giardia lamblia HAA5 Lead Legionella TTHMs Viruses | ||
| Not Appropriate for Revision at this Time | Health effects assessment in process or potential nominee for an assessment (32 NPDWRs) | Alpha particles (or emitters)1 Antimony Arsenic Asbestos Benzo(a)pyrene1 Beryllium Beta particles and photon emitters1 Cadmium Carbon tetrachloride1 Chromium Cyanide 1,2-Dichlorobenzene 1,4-Dichlorobenzene 1,2-Dichloroethane1 cis-1,2-Dichloroethylene trans-1,2-Dichloroethylene |
Dichloromethane1 Di(2-ethylhexyl)adipate1 Di(2-ethylhexyl)phthalate1 Ethylbenzene Fluoride Nitrate Nitrite Pentachlorophenol1 Polychlorinated biphenyls (PCBs)1 Radiums1 Selenium Styrene 2,3,7,8-TCDD (dioxin)1 Thallium 1,2,4-Trichlorobenzene Uranium | |
| NPDWR remains appropriate after data/information review(8 NPDWRs) | Dalapon Dinoseb Endrin Ethylene Dibromide (EDB) Mercury (inorganic) |
Methoxychlor Monochlorobenzene (chlorobenzene) 2,4,5-Trichorophenoxy-propionic acid (2,4,5-TP) | ||
| New information, but no revision recommended because: | Low priority (24 NPDWRs) |
Alachlor Barium Benzene Chlordane 1,2-Dibromo-3-chloropropane (DBCP) 1,1-Dichloroethylene 1,2-Dichloropropane 2,4-Dichlorophenoxyacetic acid (2,4-D) Diquat Endothall Glyphosate |
Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene Lindane Oxamyl Picloram Toluene Toxaphene 1,1,1-Trichloroethane 1,1,2-Trichloroethane Xylenes Vinyl chloride | |
|
Emerging information or data gaps |
Atrazine Carbofuran |
Simazine | ||
| Candidate for Revision | Based on new information (4 NPDWRs) | Acrylamide2 Epichlorohydrin |
Tetrachloroethylene (PCE)2 Trichloroethylene (TCE)2 | |
|
1. For these compounds, there is no potential to change the MCL based on changes in analytical feasibility or there may be a potential change to the MCL based on analytical feasibility but any such change is unlikely to provide a meaningful opportunity to improve public health protection. Therefore, EPA chose to leave these in the ongoing health assessment category. 2. Note that a health assessment is in process but new analytical feasibility and TT information may justify a revision. | ||||