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Stage 2 Disinfection Byproduct Rule Proposal

Stage 2 Disinfection Byproduct Rule Proposal . Stage 1 Disinfection Byproducts Rule (DBPR). DBP MCLs: TTHM 80 ug/L as a running annual average (RAA) HAA5 60 ug/L as an RAA Bromate 10 ug/L as a RAA Enhanced Coagulation/Softening Treatment Technique requirement.

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Stage 2 Disinfection Byproduct Rule Proposal

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  1. Stage 2 Disinfection Byproduct Rule Proposal

  2. Stage 1 Disinfection Byproducts Rule (DBPR) • DBP MCLs: • TTHM 80 ug/L as a running annual average (RAA) • HAA5 60 ug/L as an RAA • Bromate 10 ug/L as a RAA • Enhanced Coagulation/Softening Treatment Technique requirement.

  3. Stage 2 DBPR Regulatory Development Process • EPA negotiated with a Federal Advisory Committee which developed recommendations • FACA met from 3/30/99 to 9/6/00 • 21 members from different stakeholder groups • Data analysis • treatment and occurrence data: ICR, National Rural Water Survey, Supplemental Surveys, State data • Cost analysis • Focus of DBP health concern on reproductive & developmental health effects.

  4. Why is the Stage 2 DBPR Needed? • DBP reproductive & developmental health effects • Epidemiology studies: miscarriage, stillbirth, birth defects, low birth weight. • Not enough data to prove causality or estimate dose levels but epidemiological studies suggest that DBPs are likely to be reproductive toxicants under appropriate exposure conditions. • Toxicology studies. • Toxicology screening studies suggest that some DBPs may be reproductive/developmental hazard • DBP cancer health effect risks • DBP levels at some sites regularly exceed MCL

  5. Stage 2 M-DBPR Advisory Committee Recommendations • Stage 2 DBPR & LT2ESWTR negotiated together. • Agreement in Principle signed September 2000. • http://www.epa.gov/fedrgstr/EPA-WATER/2000/December/Day-29/w33306.htm • Consensus on Stage 2 DBPR recommendations • Phased MCLs: locational running annual average • LRAA = annual average at each monitoring site • Phase 1: TTHM/HAA5 = 120/100 ug/L • Phase 2: TTHM/HAA5 = 80/60 ug/L • Initial distribution system evaluation (IDSE) to find new compliance monitoring sites at points with highest DBP levels. • System compliance schedules

  6. Basis for LRAA & IDSE • Intent of rule is to focus on DBP peaks • Peaks in DBP levels in distribution system when compliance based on RAA. • Populations in different parts of the distribution system will receive equitable health protection. • Do Stage 1 DBPR compliance sites capture the highest DBPs in the distribution system? • Maximum residence time locations do not always capture highest DBP occurrence. • TTHM & HAA5 highest levels often occur in different places.

  7. Who is Required to Comply with the Stage 2 DBPR? • Community and nontransient noncommunity water systems that add a primary or residual disinfectant other than ultraviolet light or deliver water that has been treated with a primary or residual disinfectant other than ultraviolet light.

  8. System Compliance Requirements • Stage 2 DBPR is very similar to Stage 1 DBPR • Change in compliance calculation from RAA to LRAA • Routine monitoring on same schedule • Some systems will monitor at one extra site. • new sites determined by IDSE • Same type of reduced monitoring provisions for systems with low DBPs • IDSE • Monitoring for 1 year or site-specific data study • Opportunities for waivers and monitoring outs • Small systems consecutive to large systems are required to comply on the same schedule as the larger system.

  9. IDSE Monitoring Requirements • Guidance for states and systems on how to select IDSE monitoring sites. • Draft guidance manual will be available at the time of proposal for recommendations from states and systems.

  10. Phased MCL Requirements • Phase 1 (monitor at Stage 1 DBPR sites) • TTHM MCL = 120 ug/L as a LRAA • HAA5 MCL = 100 ug/L as a LRAA • Systems must continue to comply with Stage 1 DBPR RAA 80/60 ug/L MCLs • Phase 2 (monitor at new sites selected from IDSE) • TTHM MCL = 80 ug/L as a LRAA • HAA5 MCL = 60 ug/L as a LRAA • Systems must monitor approximately every 90 days

  11. Routine Monitoring Requirements * Sys 500-9,999: State may determine that highest HAA5 & highest TTHM are at same location. ** Sys <500: State may determine that highest HAA5 & highest TTHM are at different locations.

  12. Compliance Schedules* Simultaneous compliance with LT2ESWTR

  13. EPA Rule Development Schedule • Draft Guidance Manual for IDSE at Proposal • Proposal Late 2001 • Final Rule Statutory Deadline May 2002 • Consistent with statutory requirements for risk balancing, EPA will finalize a Long Term 2 Enhanced Surface Water Treatment Rule along with the Stage 2 Disinfectants and Disinfection Byproducts Rule, to ensure a proper balance between microbial and disinfection byproduct risks (Section 1412(b)(5)).

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