Transcript March 10, 2005

Potential Approaches for Addressing
Groups of Contaminants
Under the Safe Drinking Water Act
National Association of Water Companies
October 11, 2010
Eric Burneson,
Acting Deputy Director,
Office of Ground Water and Drinking Water
Overview
• Primary objective – Discuss and solicit input on potential
contaminant group(s) for EPA to consider for regulatory action,
and the approaches for addressing contaminant groups.
• Outline
 Background
• SDWA Regulatory Processes
 SDWA Regulatory Processes and Opportunities to Consider
Contaminant Group(s)
 Defining Groups - Factors to consider in developing groups
 Preliminary Analysis of Contaminant Groups
Office of Ground Water and Drinking Water
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Statutory Requirements for the Various Drinking
Water Regulatory Processes
(1996 SDWA Amendments)
1)
Contaminant Candidate List (CCL) – SDWA requires EPA to develop a list of
contaminants that are known or anticipated to occur in drinking water and to publish the
list every five years.
2)
Regulatory Determination for CCL – EPA must decide whether or not to regulate at
least five CCL contaminants with a national primary drinking water regulation (NPDWR)
after evaluating criteria specified under the 1996 SDWA; Publish determinations on a five
year cycle.
3)
Unregulated Contaminant Monitoring – SDWA requires EPA to establish criteria for a
program to monitor unregulated contaminants, and to identify no more than 30
contaminants to be monitored, every five years.
4)
Regulation Development - If EPA decides to regulate a contaminant via the regulatory
determination process, the Agency has 24 months to propose and 18 months to finalize
the Maximum Contaminant Level Goal (MCLG) and the NPDWR. SDWA requires that
we evaluate a number of components as part of the standard setting process.
5)
Six Year Review – Once a contaminant is regulated, EPA is required to review and, if
appropriate, revise the existing National Primary Drinking Water Regulation (NPDWR)
every six years. If make a decision to revise a standard, SDWA requires that we
evaluate a number of components as part of the standard setting process.
Office of Ground Water and Drinking Water
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Opportunities within SDWA Processes to
Consider Contaminant Group(s)
Draft CCL1
Final CCL
Preliminary
Regulatory
Determinations1
Draft UCMR
Final Regulatory
Determinations
Proposed Rule
(NPDWR1,2)
Final UCMR
UCMR Monitoring
Results
No further action if make
decision to not to regulate (may
develop health advisory).
Final Rule
(NPDWR)
Six Year Review
of Existing
NPDWRs
1. For these three stages, like to have increased specificity and confidence in the type of supporting data used (e.g. health
and occurrence).
2. When setting the NPDWR, SDWA requires that we: (a) establish the MCLG, (b) set MCL as close as feasible to the MCLG,
(c) if cannot establish an MCL (because no reliable/feasible method to measure), establish a Treatment Technique (TT), (d)
consider maximizing health risk reduction benefits at a cost justified by the benefits in setting the standard.
Office of Ground Water and Drinking Water
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Defining Group(s)
Potential Factors to Consider
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Has similar health effect endpoint
Removed by common treatment or control
processes
Measured by common analytical method(s),
directly or indirectly, under full scan
[Known or likely co-occurrence]
The more “promising” groups are likely to have many
of these factors in common.
Office of Ground Water and Drinking Water
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Examples of Currently Regulated Groups
Common Health
•
Gross Alpha* (essentially group MCLG and MCL)
One Method
 MCLG = Zero (carcinogens); MCL = 15 pCi/L (based on feasibility and risk)
 Measure “gross alpha” with a single method to determine if exceed MCL
 If exceed 15 pCi/L MCL, then measure uranium
 Subtract uranium from gross alpha, if still exceed, then speciate to find culprit(s)
•
Beta Photon/Particle Emitters** (also group MCLG and MCL)
Common Health
 MCLG = zero (carcinogens); MCL = 4 mrem/yr (dose)
One Method
 Measure gross beta/photon emitters (allowed to subtract Potassium 40)
 Convert from pCi/L to dose; if exceed then speciate to find culprit(s)
•
Haloacetic Acids (HAA 5)
 Individual MCLGs for some; Group MCL = 0.06 mg/L
 Measure and add individually to determine if exceed MCL
•
Viruses
 MCLG = zero; Specifies Treatment Technique
Common Method
Common Control Process
Common Control
Process
•Covers ~ 58 alphas (if don’t include the short lived alphas)
** Covers ~179 individual beta and photon emitters; EPA could have established individual MCLGs of zero for each one but concluded that
“despite differences in radiation type, energy, or half-life, the health effects from radiation are identical, although they may occur in different target
organs and at different activity levels” (56 FR 33050, July 18 1991 at p. 33079).
Office of Ground Water and Drinking Water
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Preliminary Evaluation
• Developed a list of all regulated and unregulated CCL 3 contaminants.
• Identified a universe of ~ 20 contaminant groups ranging from broad
categories (e.g. SOCs) to more narrow categories (e.g. nitrosamines).
• Evaluated the contaminants in the contaminant groups: (1) the critical
health endpoint(s), (2) the various treatments used to treat/control each
contaminant, and (3) the various analytical methods that can be used to
measure the contaminant.
• Groups with more factors in common represented viable groups; those
having limited commonalities unlikely to be good groups.
• As expected, we found limited convergence of factors for broad groups
(e.g. all SOCs, pesticides, etc.) so unlikely candidates for groups.
• Identified groups for further evaluation and potential regulatory
consideration for near term and other groups with more data gaps for
future consideration.
Office of Ground Water and Drinking Water
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Groups Initially Identified
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Volatile Organic Compounds (VOCs)
Synthetic Organic Compounds (SOCs)
Inorganic Compounds (IOCs)
Carcinogenic VOCs
Non-carcinogenic VOCs
Pesticides
Carbamates
Organophosphates
Chloroacetanilides
Triazines
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Conazoles
Disinfection Byproducts
Nitrosamines
Perfluorinated compounds
(PFOS/PFOA/PFCs)
Estrogenic Compounds
Androgenic Compounds
Pharmaceuticals
Antibiotics
Cholinesterase Inhibitors
Thyroid Inhibitors
Office of Ground Water and Drinking Water
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Defining Groups
Examples of Broad Groupings
Factors
Broad based groupings
SOCs (74)
Pesticides (103)
IOCs (26)
VOCs (45)
Similar
Health Effect
Endpoints?
Cancer
Cholinesterase
Inhibition
Developmental
Cholinesterase
Inhibition
Cancer
Neurological
Developmental
Testicular
Uncommon - Various Carcinogens
critical effects.
Neurological
Common
Analytical
Method (s)?
525.2 (26)
Other methods (16)
No DW methods (32)
525.2 (20 chems)
551 (13)
508 (13)
+ other methods
200.8 (15)
200.7 (1) + other
methods (8)
No DW methods (2)
524.3 + other
methods
No DW methods (10)
Common
treatment or
control
process
Typically GAC, RO, NF
Typically GAC,
AOP, Ozone,
RO/NF
Typically RO, IX,
Coag/Sed, NF
Typically Aeration,
GAC
Office of Ground Water and Drinking Water
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Groups for Potential Regulatory
Development (Near term)
Office of Ground Water and Drinking Water
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Carcinogenic VOCs
Regulated (8) Benzene
Carbon tetrachloride
1,2-dichloroethane
1,2-dichloropropane
Dichloromethane
Tetrachloroethylene
Trichloroethylene
Vinyl chloride
Unregulated CCL3 (8) Aniline
Benzyl chloride
1,3-butadiene
1,1-dichloroethane
Nitrobenzene
Oxirane methyl
1,2,3-trichloropropane (TCP)
Urethane
• All carcinogens (MCLG for each is set at zero)
• Common analytical methods (524.3/524.2, 502.2)
• Common treatment (Aeration and GAC)
• Some degree of co-occurrence (based on compliance monitoring data)
(SDWA allows setting MCLs as close to MCLG as feasible; MCL for each of these regulated
carcinogens is set at the quantitation limit; consider setting a total carcinogenic VOC MCL
for group based on feasibility)
• All carcinogens (such that any MCLG would likely be zero)
• Common methods (524.2 and/or 524.3) for a few (i.e., 1,2,3-TCP, 1,1dichloroethane, nitrobenzene and 1,3-butadiene)
• Effective treatment technologies (Aeration and GAC) for most of the 8
except for 2 (oxirane methyl and urethane)
• Degree of co-occurrence with regulated VOCs unknown at this time
(Potentially include in total VOC MCL until individual MCLs established)
Office of Ground Water and Drinking Water
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Nitrosamines
Unregulated CCL 3 (5) N-nitrosodiethylamine (NDEA)
N-nitrosodimethylamine (NDMA)
N-nitroso-di-n-propylamine (NDPA)
N-nitrosodiphenylamine
N-nitrosopyrrolidine (NPYR)
• Common health effect (carcinogens so likely MCLG
could be set at zero)
• Common analytical method (521) used to measure
• Common opportunities to reduce formation/exposure
 Modify the disinfection process by adding oxidants (e.g.,
free chlorine, ozone, other) prior to ammonia application
 Manage polymer addition
 Use TTHM/HAA5 precursor removal treatment in lieu of
chloramines
 Consider source water protection as well
• If regulated as group, could consider total MCL, treatment
technique, or combination of two concepts
Office of Ground Water and Drinking Water
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Chlorinated DBPs
Regulated Chloroform
Bromodichloromethane
Dibromochloromethane
Bromoform
Monochloroacetic acid
Dichloroacetic acid
Trichloroacetic acid
Monobromoacetic acid
Dibromoacetic acid
Unregulated
100s of unregulated
Chlorinated DBPs
• Common health endpoint (bladder cancer); Substantial bladder
cancer risk remains post-Stage 1 and Stage 2 DBPR (so could set
MCLG of zero for bladder cancer risk for chlorinated DBPs as
supported by epi studies)
• Some stakeholders advocated a treatment technique approach to
capture many contaminants; may be more applicable to this group
- Common treatment technique approach - Remove DBP precursors
(total organic carbon or TOC) prior to disinfection to reduce DBP
exposure and risk
-Common analytical measure/indicator - use TOC (e.g., lower
concentration bound and/or percent removal) as a performance
measure because it is easy to monitor and allows for treatment choice
flexibility (e.g., enhance coagulation, oxidation/filtration, GAC, and/or
membranes) to achieve TOC performance metric.
•Technologies/approaches used to remove DBPs precursors and
DBPs could also reduce other contaminants
• Source water protection could also be used to achieve TOC metric
(contributes to removal of organic and nitrogenous material )
Office of Ground Water and Drinking Water
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Potential Groups for Future
Consideration
• Perfluorinated compounds (7)
 Common health effects & treatment
 Common methods for PFOS &PFOA
 Limited occurrence data
• Organophosphate pesticides (31)
 Similar health effects & common treatment
 Methods for 4 of 31 compounds
 Some measured & modeled occurrence
• Carbamate pesticides (11)
 Similar health effects & common treatment
 Methods for 3 of 11 compounds
Office of Ground Water and Drinking Water
Groups Under Consideration with
Issues & Challenges
• Triazine pesticides (6)
 Common treatment & health effects
 Ongoing risk assessment
• Chloroacetanilides (9)
 Similar health effects & common treatment
 Common analytical methods
 Minimal occurrence in UCMR 2
• Cyanotoxins (3)
 Common source – algal blooms
 Range of health effects
 Analytical methods are challenging
Office of Ground Water and Drinking Water
Regulatory Development
• When proposing/ promulgating drinking water regulations, SDWA
requires EPA to:
 Establish (non-enforceable) maximum contaminant level
goals (MCLG)
 Determine the “feasible” level for the enforceable maximum
contaminant level (MCL) or if it is not feasible to measure
the level of the contaminants, establish a treatment
technique (TT) that prevents adverse effects to the extent
feasible
 Estimate the health risk reduction costs and benefits of
alternative MCLs or TTs
 Determine if benefits justify the costs at the feasible level
 Identify feasible technologies and affordable compliance
technologies for small systems
Office of Ground Water and Drinking Water
Regulatory Development
Potential Approaches for Groups
• Standard approach
 individual MCLs and/or a total group MCL
• Hazard Index &r Relative Potency Factor
 Methods for deriving group MCLG and/or MCLs
• Summation of Cancer Risk
 method for assessing benefits of groups of carcinogens
• Treatment barrier approach
 Require treatment in those systems likely to have
contaminant group members
 Identify monitoring parameters that reflect the removal of the
contaminants in the group
Office of Ground Water and Drinking Water
Next Steps
• EPA Science Advisory Board
consultation
• Selection of initial contaminant group
• Begin development of proposed
regulation for contaminant group
Office of Ground Water and Drinking Water