# Presentation: 915557

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

- Irene Suzukida Dooley
- Office of Ground Water and Drinking Water
- June 14, 2000

## Arsenic History

**1942**
**PHS**
**50 μg/L**

**1975**
**NIPDWR**
**50 μg/L**

**1986**
**SDWA**
**Revise by **
**1989**

**1989**
**Citizen**
**Suit Filed**

**1985**
**RMCL**
**proposed**
**50 μg/L**

**1994**
**Court Orders **
**proposal**
**by 11/95**

**1996**
**SDWA**
**amended**

**2/95**
** ****EPA**
**delays proposal**

**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

## 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)

## Key MCL Analyses

- Do benefits
- justify costs
- at MCLG
- ?

- MCL set at
- feasible level

- Yes

- Consider raising proposed MCL

- No

- 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

## NRC Report (3/99) -- Health Effects

- NRC Report (3/99) -- Health Effects

-   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.

## 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.

## 21/9% > 5 ppb

**21/9% > 5 ppb**
**7/1% > 10 ppb**
**3/0.4% > 20 ppb**

**15/1% > 5 ppb**
**6/0.4% > 10 ppb**
**2/0.1% > 20 ppb**

**13/4% > 5 ppb**
** ****6/0.8% > 10 ppb**
** ****2 /0.1% > 20 ppb**

**25/7% > 5 ppb**
**12/3% > 10 ppb**
**5/1% > 20 ppb**

**10/1% > 5 ppb**
**4/0.3% > 10 ppb**
**1/0.1% > 20 ppb**

**0.5/0.03% > 5 ppb**
**0.2/0.001% > 10 ppb**
**0.1/0% > 20 ppb**

**0./0.1% > 5 ppb**
**1/0.1% > 10 ppb**
**0.1/0.001% > 20 ppb**

**% GW/%SW >Arsenic concentration**

**Notes:**
We derived the national estimate of arsenic occurrence in three steps using the 25 State database.  (1)  Estimated system means within each State, (2) Estimated State distributions of system means, and (3) Estimated national distribution of means.  

We developed separate estimates for ground water and surface water systems.  We found that distributions did not vary significantly for different system sizes, which made the calculations simpler.

(2) We used the distribution of means within States, weighted by the number of CWS within the States to derive a Regional distribution. 

(3) To estimate the national distribution, we grouped the States into the seven regions developed by Michelle Frey and Mark Edwards in the National Arsenic Occurrence Survey.  We weighted the regional distribution estimates by the total number of CWS within that area.

Ground water tends to have higher levels of arsenic than surface water.  The North Central, Midwest Central, and New England areas had 2-10 μg/L, while the West had more > 10 μg/L.  However, systems in other areas may have hot spots and all States have systems with no detected arsenic.  

## Comparison of National Estimates(9/99 Occurrence Report had external peer review)

**     ****Arsenic level (ppb)**
**     ****Shown without confidence intervals**

**% of CWSs greater than:**

**Note: NAOS did not provide estimates at 20 ppb**

- % gw CWS >   EPA    USGS
-     2 μg/L         27%    25%
-     5 μg/L         12%    14%
-   10 μg/L           5%    7.6%

**Notes:**
The NAOS estimate are based on a survey, and contains 435 predicted finished water arsenic for more than 400 CWSs.

The USS analysis is based over 17,000 samples of ambient, ground water from almost 50% of the counties in the U.S.  

EPA used monitoring data from more than 19,000 CWSs in 25 States.  

When we compare the EPA national estimate to the NAOS estimate as summarized graphically, EPA’s estimates were higher than NAOS at 2 ppb, relatively similar at 5 ppb 10.3% vs. 11.5%, and the same at 10 ppb (4.5%).  NAOS did not provide estimates for 20 ppb.

For groundwater CWSs, EPA estimates at 2 ppb (27%) vs USGS 25%, at 5 and 10 ppb, USGS estimates were slightly higher than EPA’s groundwater CWS estimates.  We would expect USGS estimates to be slightly higher than EPA’s estimates, since they compare raw source and finished water values.

## 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

## National Annual Costs in Millions of $

**MCL    90th P  risk     CWS****1,2**** & NTNCWS ****2,3****     #       Population**
**ppb   Bladder cancer    State & EPA Admn    CWS****            **
**	****                           **
**   ****3      4-6x10****-5****                 $650              10,500     35.7 M**
**           **
**  ****5****4****      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**
**                  **
**1****Costs 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.**

**National Annual Costs in Millions of $**
**(annualized at 3%)**

## Proposed Regulationwww.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)

**Notes:**
Most of the existing analytical methods can detect from 0.5 to 1 ppb.  We are proposing to withdraw approval for EPA method 200.7 and Standard Methods 3120B because the detection limit for inductively coupled plasma-atomic emission spectroscopy are not adequate at the proposed MCL of 5 ppb, and even at the level of 10 ppb, we would withdraw those methods.
As proposed, we are requiring NTNCWS to monitor and report to the public under the Public Notification rule, 3 years after promulgated.   Unregulated, we calculate that the 90th percentile lifetime risk of bladder cancer for school children and day care children center around 10-5.

Over 95% of all school children are served by CWS, and only 12% of those served by NTNCWS (<0.5% of all students) would have arsenic > 5 ppb.  

## Next Steps for Arsenic

**1/1/00**
**statutory deadline for  proposal**

- OMB
- 90-day review begins
- mid-Feb.

- OMB 90-day review
- ends
- mid-May

**Early June 2000**
**proposal in Federal Register **

**By January 1, 2001 final rule in Federal Register **

**2004 effective date for large systems**

**2006**
** ****effective**
** ****date for **
**systems**
**< 10 K**

- 2001
- guidance
- manuals

- July 1, 2002
- CCR for 2001
- >new MCL

**Notes:**
The 90-day comment period will end in early September, 90 days after the proposal is published in the Federal Register.  The references listed in the notice include the technical support documents for occurrence; analytical methods and the PQL; treatment technologies, cost, and decision tree; risk characterization; and the regulatory impact analysis. 

While we propose only reporting and public notification for NTNCWSs, we can issue our final rule to fully regulate them.