# Presentation: 853245

## A Secondary Standard for MTBE

- Rachel Y. Sakata
- Office of Ground Water and Drinking Water
- U.S. EPA
- May 9, 2000

## Overview

-  Agency Actions on MTBE
-  The Secondary Standard - Rationale and Basis

**Notes:**
1st bullet
Provide an overview of Agency actions in regard to MTBE

2nd Bullet
Discussion of the secondary standard and its development

3rd bullet
Schedule for MTBE in the Agency

## EPA Actions Concerning MTBE - A Cross-Program Approach

- Blue Ribbon Panel:  Findings and recommendations for controlling MTBE
- EPA recommendation for Congressional waiver of oxygenate mandate
- Control or eliminate use through Toxic Substances Control Act (TSCA)
- Secondary drinking water standard for taste and odor guidelines

**Notes:**
1st bullet  EPA has a linked approach to dealing with MTBE-First there was the BRP
 Convened in January 1999 - experts in leading fields to investigate issues concerning MTBE
 At the end of 6 months released a report with their findings, stating that while MTBE does provide clean air benefits, the threat of water contamination needs to be eliminated.  
 Recommended that MTBE either be banned or eliminated; also had a number of recommendations to protect drinking water supplies.  Some of these recommendations include (1) accelerating the source water assessments, particuarly in RFG areas; (2) speed up implementation of the UCMR; (3) enhancing efforts to protect lakes and reservoirs; and (4) education on proper handling of gasoline EPA is following these recommendations through a 3 pronged effort.
 On March 20, 2000, Administrator Browner and USDA Secretary Glickman announced a number of actions to address MTBE. 
 As a result, EPA has been working with Congress to try and eliminate the oxygenate mandate
 Under the programs, gasoline sold in RFG (ozone)areas must contain 2% oxygen by weight.  In Oxyfuels (CO) areas gasoline must have 2.7% oxygen by weight.  
 EPA is trying to get Congress to eliminate these controls to allow refiners more flexibility and to help promote the use of ethanol

## TSCA Rulemaking

- TSCA Section 6 - unreasonable risk provision
- ANPRM published March 24, 2000
- Intends to eliminate or greatly reduce the use of MTBE as a gasoline additive
- Proposed TSCA rule anticipated later this year

**Notes:**
1st bullet
 Under TSCA Section 6, EPA is seeking to address MTBE under the unreasonable risk provision, indicating that MTBE poses a significant environmental risk to public drinking water supplies.  
 Due to MTBE’s offensive taste and odor, public water supplies are often shut down because the water becomes undrinkable to the users.
 Therefore, at these levels, PWS are faced with the dilemma that their water supplies could become unpotable to the public, which presents a risk to the drinking water supply.

2nd bullet
  Addresses water contamination, sources of contamination, and the difficulty in treating MTBE.  
Consideration of a total ban on MTBE, or limiting the amount of MTBE in particular areas during particular times.
 Also, requests comment  on whether the Agency should take action to address other fuel additives than MTBE.
 As you can see, this is a busy year for MTBE and the Agency.  EPA has many actions underway to address MTBE.  While putting together the TSCA rule we are also concentrating our efforts on the secondary.

## Secondary Drinking Water Standards under SDWA

- Section 1401(2) of SDWA
- Secondary drinking water standards may apply to any contaminant which:
- “(a) may adversely affect the odor or appearance of such water and.....cause a substantial number of persons served by the public water system... to discontinue its use, or
- (b) ...may otherwise adversely affect the public welfare”

**Notes:**
To give some background on the secondary

## Secondary Standard - Rationale

- Public Confidence - Sets standard in CFR as a guideline
- Increasing number of detections in public drinking water supplies
- Unregulated Contaminant Monitoring Rule and reporting in the Consumer Confidence Reports (CCR) will increase local awareness
- Meeting aesthetic level should protect against potential health effects
- Health effects still not understood

**Notes:**
1st bullet
 While most of these levels are below EPA’s DW Advisory levels, they are still of concern to the public. (for example the 60 minutes interview)
 USGS figures show 8% detection in PWS in NE states 
 UCMR provides a means by which we can obtain MTBE occurrence information across the nation.  Beginning in Jan. 2001, PWS will be required to monitor for MTBE.  Of note, this information will be reported in the Consumer Confidence Reports, which also means people will ask questions about the data.  

3rd sub-bullet
Primary standard not justified
 Under the criteria established by SDWA to regulate a contaminant, it states that NPDWR must be based on known adverse health effects, whether it will occur at levels posing a threat to public health, and if it presents a meaningful opportunity for health risk reduction. (mention 1st sub bullet then go to 2nd)
 EPA is undergoing a number of studies to better understand the human health effects of MTBE via ingestion of DW.  The Office of Research and Development has conducted a pharmacokinetic study to look at the effects of MTBE through the oral, dermal, and inhalation routes of exposure. A workshop will be held this Spring to look at the data and existing inhalation data to determine whether it can be extrapolated for drinking water exposures. EPA believes MTBE to be of concern to the Agency and through the secondary standard hopes to provide states and water systems with more direction.

## Basis Behind the Secondary Standard Level

-  EPA’s Drinking Water Advisory
- published December 1997
- guideline of 20-40 ug/L based on taste and odor effects
- Malcolm Pirnie study, June 1998

**Notes:**
 DW Advisory examined the available taste and odor studies conducted to determine a range by which the public can be protected against unpleasant taste and odor effects.
 Advisory notes that some more sensitive members of the population may detect MTBE below this range. 

 The Malcolm Pirnie study was conducted using a consumer panel (as opposed to expert panel) and with a much larger pool of participants.  While we are still evaluating this study, their analysis was that 15 ppb was protective against adverse taste and odor effects.

EPA is continuing to evaluate the data presented in the Pirnie study and re-examine the DW Advisory.

## Practical Effects of Secondary Standards 

-  Results of survey of States on secondary standards and MTBE
- 21 States currently adopt secondary standards
-  11 States enforce these standards
-  Specific to MTBE:
- 8 States adopted guidelines based on taste and odor

**Notes:**
Since secondary standards are non-enforceable it is up to the State to set stricter controls on standards.  Based on our information, 11 States currently enforce their secondary standards.

Most of the States that have adopted guidelines for MTBE are based on the current drinking water advisory.  Only Maryland, New Hampshire, and California have established lower taste and odor standards, of 10ppb, 15ppb, and 5 ppb, respectively.    California’s 5 ppb is an enforceable standard.

Only CA set their standard on the lowest detection threshold by an individual

If people detect MTBE in water, they won’t want to drink it.  Therefore, water systems will be forced to act regardless of an enforceable standard

## Contact Information

- Rachel Y. Sakata
- Office of Ground Water and Drinking Water
- U.S. EPA
- Voice:  202-260-2527
- Facsimile:  202-260-3762
- E-mail:  sakata.rachel@epa.gov