Arsenic in Drinking Water Regulation EPA Mining Waste Scientist-to-Scientist Meeting

1. Arsenic in Drinking Water Regulation EPA Mining WasteScientist-to-Scientist Meeting Irene Suzukida Dooley Office of Ground Water and Drinking Water June 14, 2000

2. Arsenic History 1985 RMCL proposed 50 µg/L 1994 Court Orders proposal by 11/95 1989 Citizen Suit Filed 1975 NIPDWR 50 µg/L 2/95 EPA delays proposal 1986 SDWA Revise by 1989 1996 SDWA amended 1942 PHS 50 µg/L 1980 CWA criterion for surface water 0.0022 µg/L 1992 CWA criterion recalculated 0.018 µg/L, IRIS update PHS: Public Health Service NIPDWR: National Interim Primary Drinking Water Regulation CWA: Clean Water Act RMCL: Recommended Maximum Contaminant Level SDWA: Safe Drinking Water Act IRIS: Integrated Risk Information System

3. What Does SDWA Require? • Arsenic (As) -- propose by January 1, 2000 and promulgate by 1/1/2001. Develop arsenic research plan (www.epa.gov/ORD/WebPubs/final/arsenic.pdf). Consult with the National Academy of Sciences (NAS), Federal agencies & interested entities.§1412(b)(12)(A) • With MCL proposals, publish a Health Risk Reduction and Cost Analysis (HRRCA) identifying quantifiable and non-quantifiable costs and benefits of each alternative, assessing health effects of sensitive sub-populations, co-occurrence and incremental costs &benefits.§1412(b)(3)(C)(i) • If the benefits would not justify the costs, EPA can choose MCL“that maximizes health risk reduction benefits at a cost that is justified by the benefits.” §1412(b)(6)(A)

4. Key MCL Analyses Identify health- based goal (MCLG) Determine technically feasible treatments and analytical methods Evaluate health benefits and costs for options, subtracting costs and benefits resulting from other proposed & finalregulations. Estimate occurrence # systems, # people Do benefits justify costs at MCLG ? Yes MCL set at feasible level No Consider raising proposed MCL

5. NRC Report (3/99) -- Health Effects www.nap.edu/books/0309063337/html/index.html • Arsenic causes skin, bladder, lung, and possibly other internal cancers in humans. [Need more research studies to understand shape of dose-response curve at low doses.] • Need more study of low-dose noncancer toxic effects - Skin - Cardiovascular and cerebrovascular diseases - Diabetes - Children - (Other noncancer effects: anemia, pulmonary disease, immunological, and neurological effects). • Not well understood how differences in age, sex, diet, nutrition, health, and lifestyles affect human variability in metabolic processing and susceptibility to arsenic.

6. NRC Report -- Risks • Current MCL of 50 µg/L is not protective. EPA needs to decrease MCL as soon as possible. - Using Taiwanese data, straight line extrapolation from 1% point-of-departure, bladder risk is 1 to 1.5 in 1,000 for 50 µg/L and margin of exposure of 8. - Poor nutrition, low selenium in Taiwain, genetic & cultural characteristics, and arsenic from food not considered. - Excess lung cancer deaths from arsenic may be 2-5 times higher than bladder cancer deaths. • Risks calculated from Chilean and Argentina studies comparable to Taiwanese risks.

7. % GW/%SW >Arsenic concentration 13/4% > 5 ppb 6/0.8% > 10 ppb 2 /0.1% > 20 ppb 15/1% > 5 ppb 6/0.4% > 10 ppb 2/0.1% > 20 ppb 21/9% > 5 ppb 7/1% > 10 ppb 3/0.4% > 20 ppb 0./0.1% > 5 ppb 1/0.1% > 10 ppb 0.1/0.001% > 20 ppb 25/7% > 5 ppb 12/3% > 10 ppb 5/1% > 20 ppb 0.5/0.03% > 5 ppb 0.2/0.001% > 10 ppb 0.1/0% > 20 ppb 10/1% > 5 ppb 4/0.3% > 10 ppb 1/0.1% > 20 ppb

8. Comparison of National Estimates(9/99 Occurrence Report had external peer review) % gw CWS > EPA USGS 2 µg/L 27% 25% 5 µg/L 12% 14% 10 µg/L 5% 7.6% % of CWSs greater than: Note: NAOS did not provide estimates at 20 ppb Arsenic level (ppb) Shown without confidence intervals

9. Treatment and Analysis • Treatment technologies can meet 3 µg/L. - Large systems: coagulation/filtration, lime softening - Small systems : ion exchange, activated alumina, reverse osmosis, nanofiltration, electrodialysis reversal • Currently approved arsenic methods - Cost $10 to 50 per test - Measure 0.5-5 ppb - Practical Quantification Level 3 ppb • Bladder cancer, assuming 100% mortality in Taiwan • Arsenic Fewer bladder Fewer bladder • cancer cases/yr cancer deaths/year • 3 µg/L 22-42 6-11 • 5 µg/L 16-36 4-9 • 10 µg/L 9-21 2-5 • 20 µg/L 4-12 1-3

10. National Annual Costs in Millions of $ (annualized at 3%) MCL 90th P risk CWS1,2 & NTNCWS 2,3 # Population ppb Bladder cancer State & EPA Admn CWS 3 4-6x10-5 $650 10,500 35.7 M 54 6-11x10-5 $380 6,600 22.5 M 10 1-1.7 x10-4 $165 3,000 10.7 M 20 1.4-2.4x10--4 $63 1,200 4.4 M 1Costs of installing and maintaining treatment technologies 2 Costs of monitoring, recordkeeping, reporting, and administration. 3 NTNCWS not required to treat 4 At 5 ppb, benefits $90 million assuming 80% Taiwanese mortality, and possibly $380 million for lung cancer based on “What If” scenario.

11. Proposed Regulationwww.epa.gov/safewater/arsenic.html • Proposed MCLG of zero. • Proposed standard of 5 ppb, asking for comment on 3 ppb, 10 ppb, and 20 ppb. • Monitoring uses same analytical methods, must report at new MCL to use for waiver data. • NTNCWS must monitor and report to the public 3 years after final rule (Public Notification rule). • Compliance 3 years after promulgation (1/2001) for CWSs serving >10,000 (2004) & 5 years after for smaller CWSs (2006)

12. Next Steps for Arsenic 2004 effective date for large systems 2006 effective date for systems < 10 K By January 1, 2001 final rule in Federal Register Early June 2000 proposal in Federal Register 1/1/00 statutory deadline for proposal July 1, 2002 CCR for 2001 >new MCL 2001 guidance manuals OMB 90-day review ends mid-May OMB 90-day review begins mid-Feb.