Federal Drinking Water Regulatory Update November 2012

Transcription

1 Federal Drinking Water Regulatory Update November 2012 Bruce A. Macler USEPA Region 9 macler.bruce@epa.gov

2 EPA DW Regulatory Status Out the door UCMR3 Proposed, closed and awaiting Final Total Coliform Rule revisions In development CCL 3 regulatory determinations Perchlorate Carcinogenic VOCs Lead and Copper Rule revisions LT2 ESWTR retrospective/ 6-year review CCR review

3 Total Coliform Rule Revisions Proposed July 14, 2010 Federal Register 75, #134, pp Expect it to go final soon At OMB for 90-day review Unclear what the hold-up is No separate proposal for storage tank inspections

4 TCR Revisions Continue to use indicators appropriate for ensuring the objectives of the TCR Use E. coli for acute fecal MCL Eliminate the use of fecal coliforms test Make total coliform detection a trigger, not MCL Corrective action/ treatment technique required No public notice for TC positives Reconsider choices for analytical methods to control false positives and negatives Change the monitoring frequencies and criteria for different systems and sources

5 Carcinogenic VOC Rule The EPA Administrator announced DW Strategy actions on February 2, 2011 Regulate perchlorate Regulate carcinogenic VOCs as a group Revise trichloroethylene (TCE) and tetrachloroethylene (PCE) MCLs Possibly revise other existing cvoc MCLs Possibly regulate cvocs from CCL3

6 Currently Regulated Carcinogenic VOCs Besides TCE and PCE, EPA has MCLs for benzene carbon tetrachloride 1,2-dichloroethane 1,2-dichloropropane dichloromethane vinyl chloride Dichlorobromopropane (DBPC) and ethylene dibromide (EDB) may also be reconsidered During the last 6-year review, EPA passed on revising these as offering too little benefit for the cost

7 Unregulated cvocs From the CCL3 Aniline Benzyl chloride 1,3-butadiene 1,1-dichloroethane Nitrobenzene Methyl oxirane 1,2,3-trichloropropane Urethane 1,1,1,2 tetrachloroethane; 1,1,2,2 tetrachloroethane also possibilities

8 cvoc Workgroup Activities Efforts to define a VOC are ongoing Not all VOCs are VOCs Novel group risk approach focuses on total public health, not each chemical Similar to gross alpha radionuclides May also be appropriate for DBPs, nitrosamines 1,2,3-Trichloropropane may be the hot one Most risky

9 What is a VOC? No clear definition or agreement High vapor pressure, low water solubility Boiling point <200 o C Henry s Law constant: > 0.01 Analysis with purge/ trap, method Can be air stripped by PTA or removed with GAC

10 Is it a VOC? These criteria would likely eliminate aniline, benzyl chloride, nitrobenzene, methyl oxirane, urethane Could eliminate 1,2,3-trichloropropane, 1,1,2,2 tetrachloroethane, DBCP It will be awhile before much happens

11 Perchlorate Regulation EPA held public regulatory workshops on analytical methods, treatment and health risks Several treatment approaches possible, but problems remain Applicability to large SW systems, like MWD Treatment waste disposal Perchlorate occurrence needs recalculating EPA asked its SAB to help define approaches for setting the health-based MCLG Final report expected in late December A proposed MCL may come out later next year

12 Perchlorate Health Risk Issues Health concerns are for damaged thyroid and brain development in fetuses and infants Perchlorate interferes with iodide uptake ~20% of women are deficient in iodide EPA asked its Science Advisory Board for guidance on MCLG development SAB supports PBPK modeling SAB supports addressing sensitive lifestages Epidemiological data considered insufficient for use

13 Contaminant Candidate List 3 Regulatory Determinations EPA has reviewed CCL3 for possible action Proposal expected late 2012 These may go forward for regulation Nitrosamines, individually or grouped 1,2,3-trichloropropane, chlorate, strontium These may be dropped as not a DW problem 1,3 Dinitrobenzene Dimethoate Terbufos & Terbufos sulfone Others on CCL3 need more health or occurrence information

14 N-Nitroso Dimethylamine NDMA is a known carcinogen ng/l Many other nitrosamines have similar risks Formed from chlorination or chloramination of wastewater UCMR 2 shows 25% of systems affected Controversy over relative contributions from food vs water vs endogenous Hot prospect, probably as nitrosamines

15 Other Possibilities 1,2,3- Trichloropropane Mutagenic carcinogen Likely pulled into carcinogenic VOCs reg Chlorate Disinfection byproduct Thyroid effects; 210 ug/l Strontium Competes with calcium in bone HRL for child ~ 1700 ug/l Not based on its radioactivity

16 Lead & Copper Rule Long-term Revisions EPA evaluating all aspects of the current rule Partial lead service line replacement Does it make a difference? Monitoring Sample site selection Lead vs copper Tap sampling issues Water quality parameters Lead in schools and day care facilities Is copper really a problem worth regulating?

17 Partial Lead Service Line Replacement Under current rule, utilities can address exceedances by replacing service lines to the meter Owners generally responsible for rest But, partial replacement may be worse than doing nothing Lead particles Galvanic corrosion Solution? All or nothing, if owners concur

18 LCR Revisions Timeline Option discussions ongoing Proposal expected 2013 Final a couple of years after that Revisions may make Rule very complex 18

19 LT2 ESWTR review NYC, Portland don t want to cover their finished water reservoirs Issues with monitoring and binning EPA reviewing data, doing site visits Public meeting Nov 15 th Any decision unlikely until 2016 ie, in next 6-Year Review

20 Consumer Confidence Report Review Interest in alternative means of sending out CCRs, besides mailing Various electronic delivery ideas EPA released draft approaches Sept 4 ccrretrospectivereview@epa.gov Will provide guidance in early 2013 Reg revision not necessary What you see is likely what you ll get

21 Chromium Trivalent chromium (Cr +3 ) is a nutrient Hexavalent chromium (Cr +6 ) is toxic CA OEHHA has a revised PHG at 0.02 ug/l for Cr +6 Considers Cr +6 carcinogenic EPA has its risk assessment out for review But EPA considering new data on Mode of Action of carcinogenicity Could result in a less stringent number

22 Cr +6 Mode of Action? Mode of Action (MOA) describes how something could be toxic For carcinogens, some can damage DNA or chromosomes directly (genotoxicity) Some carcinogens kill cells; healing process can trigger cancer (cytotoxicity) CA OEHHA considers Cr +6 primarily genotoxic No level of exposure is completely safe Other data indicate that Cr +6 cytotoxicity dominates at lower exposures A threshold level for effects could exist

23 Federal Regulatory Changes for Chromium? Federal MCL is 100 ug/l (CA is 50 ug/l) Essentially a Cr +6 MCL Based on general toxicity, not cancer Cancer risk points to a downward revision But Cr +6 is 5 x less risky than arsenic Will get occurrence info from UCMR3 Treatment and costs are a big deal Unclear if existing technologies are adequate Residuals management is expensive Next 6-year Review will consider it

24 Nitrate Pacific Institute issued report on nitrate problems in San Joaquin Valley Nitrate (nitrite) can lead to methemoglobinemia in infants Very rare, though (ave 3 cases/year in US) Often not DW related at all Usually related to diarrhea Not an issue for adults at DW levels Cancer data equivocal Nitrate<nitrite<nitrosamines

25 Final Thought: Drinking water from a public supply is about the safest thing you do 25