# Presentation: 698189

## The Safe Drinking Water Act and Perchlorate

**MIKE OSINSKI**
**Office of Ground Water and Drinking Water**
**U.S. Environmental Protection Agency**
**Washington, D.C.**
**202-260-6252**
**202-260-3762 (fax)**
**OSINSKI.MICHAEL@epamail.epa.gov**

## Contaminant Identification and Selection Under the SDWA 

**Contaminant Selection Under the 1986 Amendments to SDWA:**
- Regulate 83 contaminants by 1989;
- Regulate 25 contaminants every 3 years.
**Congress, EPA had Implementation Concerns:**
- Missed statutory deadlines;
- Water systems encountered difficulty in timely compliance;
- Focus on sound science and contaminants posing greatest risk.

## Contaminant Identification and Selection Under the SDWA

**Contaminant Selection Under the 1996 Amendments to SDWA.**
- Publish a Contaminant Candidate List (CCL) of contaminants known or anticipated to occur in DW and not subject to NPDWRs by Feb 1998.
- Broad consultation with stakeholders, NDWAC, and SAB.

## Contaminant Identification and Selection under the SDWA

**Draft CCL Published on Oct 6, 1997.**** **
- Did not include perchlorate, but sought comment on whether to include it on the final CCL.
- Public comments indicated overall support for adding perchlorate to the CCL.
**Final CCL published on March 2, 1998**.
- Contains 50 chemical and 10 microbiological contaminants.

## Contaminant Candidate List (CCL)

**Functions of the CCL:**
- Make determinations for at least 5 contaminants of whether or not to regulate with a NPDWR by 2001.
- Focus and prioritize research agenda for contaminants with data gaps.
- Source for selection of contaminants for unregulated contaminant monitoring regulation (UCMR) due in 1999.

## Perchlorate and the CCL

**Two categories of contaminants on the CCL:**
- (1) Regulatory Determination Priorities;
- (2) Research Priorities.
**Perchlorate falls into the research priorities category due to extensive data gaps in:**
- Occurrence; health effects, treatment technologies, and analytical methods research.

## Regulatory and Policy Agenda for Perchlorate 

**Determination to regulate not likely by 2001.**
- Extensive data gaps in all areas.
**EPA is not currently planning to include perchlorate as a contaminant in the proposed UCMR (Fall 1998).**
- Lack of EPA approved analytical method(s).
- Recommend near-term special occurrence studies.

## Next Steps for Perchlorate

**Perchlorate is a research and occurrence **_**priority**_** for the OGWDW.**
- In process of developing short and longer term research plans on health, treatment, and analytical  methods.
**OGWDW is very engaged in the IPSC.**
- Ensure exchange of scientific information to support decision making based on sound science and stakeholder involvement.

## Next Steps for Perchlorate

**Possible Scenarios:**
**(1)**** ****Longer Term (3 to 5 years):  **
- Data gaps filled and perchlorate moves to the regulatory determination priority category of next CCL -- due in 2003.
**(2) Near Term (1-2 years):**
- If health effects and occurrence data warrant, develop a Health Advisory.

## EPA Health Advisory Program

**SDWA General Authority:**
- “The Administrator may publish health advisories (HA), which are not regulations, or take other appropriate actions for contaminants not subject to any national primary drinking water regulation.”
**HAs represent concentrations of contaminant in drinking water which adverse health effects are not expected to occur.**

## EPA Health Advisory Program

**Not federally enforceable.**
**Subject to change as new information becomes available.**
**Can serve as technical guidance to assist State, Tribal, and local officials responsible for protection of public health.**

## EPA Health Advisory Program 

**HAs used in emergency situations and describe concentrations of a contaminant at which adverse non-carcinogenic effects are not anticipated to occur following exposures:**
- 1-day
- 10-day :
- Longer term (i.e. 7 years)
- Lifetime

## Sample HA Calculations

**Determine RfD in mg/kg/day.**
**Determine DWEL (Drinking Water Equivalent Level) in mg/L, assuming 100% drinking water contribution.**
**Determine HA in mg/L.**

## Sample HA Calculations

-       DWEL (mg/L) = (_RfD)(70 kg adult_)*
-                 	                           (2 L/day)
-   	       DWEL (mg/L) = (_RfD)(10 kg child_)**
-                                                 (1 L/day)
- *    *for lifetime HA*
- ** *for 1 day, 10 day, and longer term HA*
-       HA (mg/L) = (DWEL)(% DW contribution)