&EPA United States Environmental Protection Agency The Third Unregulated Contaminant Monitoring Rule (UCMR 3): Data Summary October 2015 EPA uses the Unregulated Contaminant Monitoring Rule (UCMR) program to collect data for contaminants suspected to be present in drinking water, but that do not have health-based standards set under the Safe Drinking Water Act (SDWA). Every five years EPA develops a new list of UCMR contaminants, largely based on the Contaminant Candidate List (CCL). The SDWA Amendments of 1996 provide for: • Monitoring no more than 30 contaminants per 5-year cycle • Monitoring only a representative sample of public water systems serving less than or equal to 10,000 people • Storing analytical results in a National Contaminant Occurrence Database (NCOD) This dataset represents the eighth NCOD release of analytical results for UCMR 3. Updates will occur approximately quarterly and EPA anticipates that additional reference material will be made available to assist with the assessment of the UCMR 3 data. For more information about UCMR 3, please visit our website: http://water.epa.qov/lawsreqs/rulesreqs/sdwa/ucmr/ucmr3/index.cfm. Information regarding many of the UCMR 3 contaminants (including a description of their use) may also be found at the CCL website: http://water.epa.gov/scitech/drinkinqwater/dws/ccl/ccl3.cfmtfchemical. UCMR 3 Data Considerations • This dataset is not complete. UCMR 3 monitoring occurs through December 2015, and data are expected to be reported to EPA through the summer of 2016. • Data are added and possibly removed or updated over the course of this reporting cycle. These results are subject to change following further review by the analytical laboratory, the public water system, the State and EPA. • Data are presented as method-specific text files (UCMR3_200_8.txt, UCMR3_218_7.txt, UCMR3_300_1.txt, UCMR3_522.txt, UCMR3_524_3.txt, UCMR3_537.txt, UCMR3_539.txt, EPA_1615A, EPA_1615B, EPA_1615C, EPA_1615D, EPA_1615E, SM_9223B, ASTM_D6503_99, SM_9218, EPA_1602), one text file containing disinfectant residual type (UCMR3_DRT.txt), one text file containing the U.S. Postal Service Zip Code(s) for all areas served by a PWS (UCMR3_ZipCodes.txt) and one text file containing all UCMR 3 data to date (UCMR3_All.txt). • These text files are tab delimited and have no text qualifier. Field names are included in the first row of each file. • If you wish to perform additional data analyses, EPA suggests you import each field into your choice of software as text. Some of the IDs can be misinterpreted as long integer field types when they actually contain alpha characters. • Samples collected at the maximum residence time in the distribution system (MR) are required to be analyzed for metals (including chromium-6) and chlorate. • Water systems monitoring for Method 300.1 (chlorate) report disinfectant types. • Population categories are based on retail population as indicated by the Safe Drinking Water Information System (Federal) (SDWIS/FED) as of December 31, 2010. • In addition to reporting occurrence data for UCMR 3 target analytes, EPA tasked its small-system contract-support laboratories with reporting results for sec-butylbenzene, n-propylbenzene, tellurium, germanium and manganese. These additional unregulated analytes are within the scope of the methods already being performed for the UCMR analytes. Office of Water (MS-140) EPA815-S-15-003 October 2015 ------- UCMR 3 Data Field Names and Definitions Field Name PWSID PWSName Size FacilitylD FacilityName FacilityWaterType SamplePointID SamplePointName SamplePointType AssociatedFacilitylD AssociatedSamplePointID Definition Public Water System Identification Code, 9-character identification code (Begins with the standard 2-character postal State abbreviation or Region code, and the remaining seven numbers are unique to each PWS in the state) Name of the Public Water System (PWS) Size category of the PWS for UCMR, based on retail population as of December 31 , 201 0 S: < 10,000 L: > 10,000 Public Water System Facility Identification Code, 5-digit identification code Name of the facility at the PWS Source of water at the facility SW: Surface water GW: Ground water GU: Ground water under the direct influence of surface water MX: Any combination of: SW, GW and GU Identification code for each sample point location in the PWS Name of the sample point for every sample point ID at a PWS Sampling Point Type Code EP: Entry point to the distribution system MR: Distribution system at maximum residence time The facility ID of the associated DS/MRT The sample point ID of the associated DS/MRT UCMR 3, October 2015 Page 2 of 12 ------- Field Name finition Disinfectant Type CLGA: Gaseous Chlorine CLOF: Offsite Generated Hypochlorite (stored as liquid) CLON: Onsite Generated Hypochlorite (no storage) CAGC: Chloramine (formed from gaseous chlorine) CAOF: Chloramine (formed from offsite hypochlorite) CAON: Chloramine (formed from onsite hypochlorite) CLDO: Chlorine Dioxide OZON: Ozone ULVL: Ultraviolet Light OTHD: All other types of disinfectant NODU: No Disinfectant Used CollectionDate Date of sample collection (month, day, year) SamplelD Identification code for each sample, as defined by the laboratory Contaminant Unregulated contaminant being analyzed in UCMR 3 MRL Minimum Reporting Level defined by UCMR 3 MethodID Identification code of the analytical method AnalyticalResultsSign Less than (<) the minimum reporting level (MRL) or equal to (=) a numeric value at or above the MRL AnalyticalResultValue Numeric value of the analytical result, null values represent less than MRL SampleEventCode Identification code for each sample event. Includes sample event one (SE1), sample event two (SE2), sample event three (SE3), and sample event four(SE4). UCMR 3, October 2015 Page 3 of 12 ------- Field Name MonitoringRequirement Region State ZipCode Definition AM: Assessment Monitoring (List 1) SS: Screening Survey (List 2) PST: Pre-Screen Testing (List 3) EPA Region: States 1: CT, ME, MA, NH, Rl, VT 2: NJ, NY, PR (Puerto Rico), VI (Virgin Islands) 3: DE, DC, MD, PA, VA, WV 4: AL, FL, GA, KY, MS, NC, SC, TN 5: IL, IN, Ml, MN, OH, Wl 6: AR, LA, NM, OK, TX 7: IA, KS, MO, NE 8: CO, MT, ND, SD, UT, WY 9: AZ, CA, HI, NV, AS (American Samoa), GU (Guam), MP (Northern Marianas Islands), NN (Navajo Nation) 10: AK, ID, OR, WA State abbreviation U.S. Postal Service zip code(s) for all areas being served water by a PWS UCMR 3, October 2015 Page 4 of 12 ------- UCMR3 Chemical Contaminants and Methods Contaminant 1 ,2,3-trichloropropane 1,3-butadiene Chloromethane 1,1-dichloroethane Bromomethane HCFC-22 Halon1011 1,4-dioxane Vanadium Molybdenum Cobalt Strontium Chromium Chromium-6 Chlorate PFOS PFOA PFNA PFHxS PFHpA PFBS 17p-estradiol 17a-ethynylestradiol Estriol Equilin Estrone Testosterone 4-androstene-3,17-dione Contaminant Full Name 1 ,2,3-trichloropropane 1,3-butadiene methyl chloride 1,1-dichloroethane methyl bromide chlorodifluoromethane bromochloromethane 1,4-dioxane vanadium molybdenum Cobalt Strontium total chromium chromium-6 Chlorate perfluorooctanesulfonic acid perfluorooctanoic acid perfluorononanoic acid perfluorohexanesulfonic acid perfluoroheptanoic acid perfluorobutanesulfonic acid estradiol ethinyl estradiol 16-a-hydroxyestradiol Equilin Estrone testosterone 4-androstene-3,17-dione BcHmifi? 96-18-4 106-99-0 74-87-3 75-34-3 74-83-9 75-45-6 74-97-5 123-91-1 7440-62-2 7439-98-7 7440-48-4 7440-24-6 N/A 18540-29-9 14866-68-3 1763-23-1 335-67-1 375-95-1 355-46-4 375-85-9 375-73-5 50-28-2 57-63-6 50-27-1 474-86-2 53-16-7 58-22-0 63-05-8 Method ID 524.3 524.3 524.3 524.3 524.3 524.3 524.3 522 200.8 200.8 200.8 200.8 200.8 218.7 300.1 537 537 537 537 537 537 539 539 539 539 539 539 539 EBi^EE^^H Volatile Organic Compounds Volatile Organic Compounds Volatile Organic Compounds Volatile Organic Compounds Volatile Organic Compounds Volatile Organic Compounds Volatile Organic Compounds Synthetic Organic Compound Metals Metals Metals Metals Metals Chromium-6 Oxyhalide Anion Perfluorinated Compounds Perfluorinated Compounds Perfluorinated Compounds Perfluorinated Compounds Perfluorinated Compounds Perfluorinated Compounds Hormones Hormones Hormones Hormones Hormones Hormones Hormones Monitoring Requirement AM AM AM AM AM AM AM AM AM AM AM AM AM AM AM AM AM AM AM AM AM SS SS SS SS SS SS SS 1Chemical Abstract Service UCMR 3, October 2015 Page 5 of 12 ------- UCMR3 Microbiological Contaminants and Methods Contaminan Enteroviruses lethod II EPA1615A ethod Name Monitoring Requirement Enterovirus cell culture PST Enteroviruses EPA1615B Enterovirus RT-qPCR ^1 I LVSI W V II MxJ I X I \J^I >uf I X Norovirus genogroup I with RT-qPCR primer set A Norovirus genogroup I with RT-qPCR primer set B PST Noroviruses EPA1615C PST Noroviruses EPA1615D PST Noroviruses EPA1615E Noroviruses genogroup II PST Total conforms SM 9223B Colilert® PST E.coli SM 9223B Colilert® PST Enterococci ASTM D6503-99 Enterolert® PST Aerobic spores SM9218 Aerobic endospores PST Somatic phage EPA 1602 Bacteriophage PST Male specific phage EPA 1602 Bacteriophage PST UCMR 3, October 2015 Page 6 of 12 ------- UCMR 3 Reference Concentrations for Chemical Contaminants Under the current cycle of the Unregulated Contaminant Monitoring Rule (UCMR 3) chemicals are being studied at levels that are often significantly below those in prior UCMR cycles. Importantly, UCMR 3 minimum reporting levels (MRLs) were established based on the capability of the analytical method, not based on a level established as "significant" or "harmful." In fact, the UCMR 3 MRLs are often below current "health reference levels" (to the extent that HRLs have been established). Results of UCMR 3 measurements should be interpreted accordingly. The detection of a UCMR 3 contaminant above the MRL does not represent cause for concern, in and of itself. Rather, the implications of the detection should be judged considering health effects information (which is often still under development or being refined for unregulated contaminants). The intent of the following table is to identify draft UCMR reference concentrations, where possible, to provide context around the detection of a particular UCMR contaminant above the MRL. The draft reference concentration does not represent an "action level" (EPA requires no particular action1'2 based simply on the fact that UCMR monitoring results exceed draft reference concentrations), nor should the draft reference concentration be interpreted as any indication of an Agency intent to establish a future drinking water regulation for the contaminant at this or any other level. Decisions as to whether or not to regulate the contaminant in drinking water will continue to be made following the Agency's Regulatory Determination process: [http://water.epa.qov/scitech/drinkinqwater/dws/ccl/index.cfml. The following key principles guided the development of the table: (1) The reference concentrations are based on publically-available health information found in the following EPA resources: 2012 Drinking Water Standards and Health Advisories, the CCL 3 Contaminant Information Sheets, the Human Health Benchmark for Pesticides (HHBPs), the Integrated Information Risk System (IRIS), or the 2014 Preliminary Regulatory Determinations for Contaminants on CCL 3. The primary/secondary sources of health information vary with respect to scientific rigor from health assessment to single studies and are cited in the table. (2) If health information was available from more than one of the EPA resources listed above, the most recent health information was used for the draft reference concentrations. (3) Where both cancer and non-cancer draft reference concentrations existed, the lower (more conservative) of the two concentrations was used. For chemicals with reference concentrations based on a cancer endpoint, the table presents a range of values associated with 10~6 to 10~4 cancer risk. For chemicals with reference concentrations based on a non-cancer endpoint, the duration of exposure (short-term, intermediate/long-term, chronic) of the toxicity factor (e.g. Reference Dose) used as the basis for the reference concentration is shown. Recognizing that additional health effects information will become available over time, EPA will periodically update the following table. Those attempting to assess UCMR occurrence data are encouraged to visit EPA's website for the most recent information. 1 Consumer Confidence Report (CCR) and Public Notification (PN) reporting requirements (see 40 CFR 141.153(d) and 141.207, respectively) apply to public water systems; CCR requires particular reporting based on measurements relative to the UCMR method reporting limits (MRLs) defined in 40 CFR 141.40. 2States may establish requirements for drinking water contaminants not yet regulated by EPA, and those requirements may be based on State-established levels that differ from EPA's reference concentrations. Public Water Systems are responsible for being aware of and complying with their State's requirements, if any. UCMR 3, October 2015 Page 7 of 12 ------- Contaminant Cobalt1 Molybdenum2 Strontium3 Vanadium1'4 Chromium (Total) Chromium-61 Chlorate 1,4-dioxane5 1,1-dichloroethane5 1 ,2,3-trichloropropane5'6'7 1,3-butadiene5'6 MRL (V9/L) 1 1 0.3 0.2 0.2 0.03 20 0.07 0.03 0.03 0.1 Reference Concentration (V9/L) 70 40 1,500 21 100 NA 210 0.35 to 35 6.14 to 614 0.0004 to 0.04 0.01 03 to 1.03 Reference Concentration based on a Cancer Endpoint (Y/N) N (intermediate exposure) N (chronic exposure) N (chronic exposure) N (intermediate exposure) N (chronic exposure) N (chronic exposure) Y Y Y Y EPA Reference(s) CCL 3 Contaminant Information Sheets 2012 Edition of the Health Advisories Table Federal Register Notice for the Preliminary Regulatory Determinations for Contaminants on CCL 3 CCL 3 Contaminant Information Sheets The MCL for the National Primary Drinking Water Regulation CCL 3 Contaminant Information Sheets 2012 Edition of the Health Advisories Table CCL 3 Contaminant Information Sheets 2009 IRIS Assessment CCL 3 Contaminant Information Sheets 1 The contaminant is on the IRIS 2012 Agenda for either a new assessment or an updated assessment (Federal Register Notice May 7, 2012). 2 The 2012 Edition of the Health Advisories Table and the CCL 3 Contaminant Information Sheets (35 u.g/L) have slightly different numbers due to rounding. 3 The reference concentration has been updated based on the HRL cited in the preliminary regulatory determination for strontium [Docket No. EPA-HQ-OW-2012-0155]. 4 The ATSDR, 1992 used for the CCL 3 Contaminant Information Sheets is no longer publically available and has been replaced by a new assessment (ATSDR, 2013). The minimum risk level (RfD equivalent) was 0.003 mg/kg/day for minor renal effects in an animal study (ATSDR, 1992) compared to 0.01 mg/kg/day for lack of minor effects in blood pressure, body weight, and hematological parameters in a human study with a 12 weeks exposure (ATSDR, 2013). 5 Reference Concentration range based on cancer risk of 10"6 to 10"4. 610'6 cancer risk < MRL < 10'4 cancer risk. 7 To derive the reference concentration, age dependent adjustment factors were applied to the IRIS oral slope factor of 30 per mg/kg-day (calculated using adult exposure data) to address presumed early-life susceptibility for this chemical (per www.epa.gov/cancerguidelines/). UCMR 3, October 2015 Page 8 of 12 ------- Contaminant HCFC-22 (chlorodifluoromethane) 8 Chloromethane (methyl chloride)5 Halon 1011 (bromochloromethane)9 Bromomethane (methyl bromide) PFBS PFHpA PFHxS PFNA PFOS PFOA 1 7a-ethynylestradiol (ethinyl estradiol)10 17(3-estradiol (estradiol)5 Equilin Estriol (16-a-hydroxyestradiol) Estrone 4-androstene-3, 1 7-dione Testosterone MRL (V9/L) 0.08 0.2 0.06 0.2 0.09 0.01 0.03 0.02 0.04 0.02 0.0009 0.0004 0.004 0.0008 0.002 0.0003 0.0001 Reference Concentration (V9/L) NA 2.69 to 269 90 140 NA NA NA NA 0.2 0.4 0.035 0.0009 to 0.09 0.35 0.35 0.35 NA NA Reference Concentration based on a Cancer Endpoint (Y/N) Y N (chronic exposure) N (chronic exposure) N (short-term exposure) N (short-term exposure) N (chronic exposure) Y N (chronic exposure) N (chronic exposure) N (chronic exposure) EPA Reference(s) CCL 3 Contaminant Information Sheets 2012 Edition of the Health Advisories Table Human Health Benchmark for Pesticides (HHBPs) 2012 Edition of the Health Advisories Table 2012 Edition of the Health Advisories Table CCL 3 Contaminant Information Sheets CCL 3 Contaminant Information Sheets CCL 3 Contaminant Information Sheets CCL 3 Contaminant Information Sheets CCL 3 Contaminant Information Sheets 8 The CCL 3 Contaminant Information Sheets provide a reference level of 31.5 u.g/L; the number is based on a single LOAEL from a 1983 study. 9 The 2012 Edition of the Health Advisories Table and the CCL 3 Contaminant Information Sheets (70 u.g/L) have slightly different numbers due to rounding. 10 This corrects the CCL 3 Contaminant Information Sheets reference level (originally listed as 0.28 u.g/L). UCMR 3, October 2015 Page 9 of 12 ------- Terms a) UCMR Draft Reference Concentration = The reference concentrations are based on publically-available health information found in the following EPA resources: 2012 Drinking Water Standards and Health Advisories, the CCL 3 Contaminant Information Sheets, the Human Health Benchmark for Pesticides (HHBPs), or the 2014 Preliminary Regulatory Determinations for Contaminants on CCL 3. The primary/secondary sources of health information vary with respect to scientific rigor from health assessment to single studies. Many of the contaminants are currently under regulatory review or development and are subject to change as new health assessments are completed. b) MRL = UCMR Minimum Reporting Level. [Note that the Agency for Toxic Substances & Disease Registry (ATSDR) uses the term "MRL'for a different purpose (i.e., to describe "Minimal Risk Levels"). The UCMR term and the ATSDR term have no relationship to each other.] c) HRLs = Health Reference Levels. HRLs are not final determinations about the level of a contaminant in drinking water that is necessary to protect any particular population and are derived prior to development of a complete exposure assessment. HRLs are risk derived concentrations against which to evaluate the occurrence data to determine if contaminants occur at levels of potential public health concern. d) MCL = Maximum Contaminant Level. The highest level of a contaminant allowed in drinking water. MCLs are enforceable standards. e) Cancer Risk of 10~6 to 10~4 = the concentration of a contaminant in drinking water corresponding to an excess estimated lifetime cancer risk of one-in-a-million (1x 10'6) to one-in-ten-thousand (1 x 10'4). The 2012 Drinking Water Standards and Health Advisories provide the cancer risk at 1 x 10'4. The CCL 3 Contaminant Information Sheets provide the cancer risk at 1x 10'6. f) LOAEL = Lowest Observed Adverse Effect Level g) NA = Not Available h) Short-term = Typically refers to animal toxicological studies with an exposure duration of days to weeks. i) Intermediate/Longer-term = Typically refers to animal toxicological studies with an exposure duration of weeks to months. j) Chronic = Typically refers to animal toxicological studies with an exposure duration of months to years; representing a lifetime exposure in humans. References k) 2012 Drinking Water Standards and Health Advisories I) CCL 3 Contaminant Information Sheets m) Human Health Benchmark for Pesticides (HHBPs) n) Announcement of Preliminary Regulatory Determinations for Contaminants on the Third Drinking Water Contaminant Candidate List o) Integrated Risk Information System (IRIS) UCMR 3, October 2015 Page 10 of 12 ------- October 2015 UCMR 3 Data Summary for Chemical Contaminants I ^^^^^^n 1 1 ,2,3-trichloropropane 1,3-butadiene Chloromethane 1,1-dichloroethane Bromomethane HCFC-22 Halon1011 1,4-dioxane Vanadium Molybdenum Cobalt Strontium Chromium Chromium-6 Chlorate PFOS PFOA PFNA PFHxS PFHpA PFBS 17|3-estradiol 1 7a-ethynylestradiol Estriol Equilin Estrone Testosterone 4-androstene-3, 1 7-dione 0.03 0.1 0.2 0.03 0.2 0.08 0.06 0.07 0.2 1 1 0.3 0.2 0.03 20 0.04 0.02 0.02 0.03 0.01 0.09 0.0004 0.0009 0.0008 0.004 0.002 0.0001 0.0003 IwSHHiffiM JSP- 0.0004 / 0.041 0.0103/1.031 2.69 /2691 6.14 /6141 140 NA 90 0.35 / 351 21 40 70 1,500 100 NA 210 0.2 0.4 NA NA NA NA 0.0009 / 0.091 0.035 0.35 0.35 0.35 NA NA of results 32,893 32,893 32,891 32,891 32,892 32,893 32,893 32,740 56,298 56,307 56,290 56,227 56,161 56,039 55,990 33,178 33,178 33,178 33,178 33,178 33,178 10,234 10,235 10,234 10,235 10,235 10,234 10,235 of results >MRL 228 1 251 764 109 742 596 3,796 33,595 23,089 772 56,038 28,378 42,151 30,991 260 324 19 192 216 13 3 4 1 0 0 57 84 Number of > Reference Concentration 228 /1741 1 /O1 18/01 1 /O1 0 -- 0 989 / O1 1,563 133 3 1,546 1 -- 8,608 33 0 -- -- -- -- 1 /O1 0 0 0 0 -- -- »/. of total Concentration 0.7% / 0.5%1 0.003% / 0%1 0.05% / 0%1 0.003% / 0%1 0% -- 0% 3% / 0%1 2.8% 0.2% 0.005% 2.7% 0.002% -- 15.4% 0.1% 0% -- -- -- -- 0.01 %/0%1 0% 0% 0% 0% -- -- results 4,750 4,750 4,750 4,749 4,750 4,750 4,750 4,746 4,756 4,756 4,756 4,756 4,756 4,756 4,749 4,764 4,764 4,764 4,764 4,764 4,764 1,145 1,145 1,145 1,145 1,145 1,145 1,145 SMRL 62 1 127 230 46 266 286 1,025 3,454 2,438 226 4,755 3,517 4,229 3,236 90 103 14 54 80 6 1 4 1 0 0 51 64 > Reference Concentration 62 / 521 1 /O1 7/01 1 /O1 0 -- 0 325/ O1 159 34 3 272 1 -- 1,744 17 0 -- -- -- -- 1/01 0 0 0 0 -- -- •3WSs with rence Concentration 1.3%/1.1%1 0.02% / 0%1 0.1% /0%1 0.02% / 0%1 0% -- 0% 6.8% / 0%1 3.3% 0.7% 0.06% 5.7% 0.02% -- 36.7% 0.4% 0% -- -- -- -- 0.09% / 0%1 0% 0% 0% 0% -- -- 1Where two reference concentrations are listed, the first number is associated with a 10'® cancer risk; the second number a 10^ cancer risk. Where two results are presented the first number is associated with the first reference concentration; the second number is associated with the second reference concentration. UCMR 3, October 2015 Page 11 of 12 ------- October 2015 UCMR 3 Data Summary for Microbiological Contaminants Aerobic spores E. coli Enterococci Enteroviruses (cell culture) Enteroviruses (RT-qPCR5) Male specific phage Noroviruses GIA8 Noroviruses GIB9 Noroviruses Gil10 Somatic phage Total coliforms 1 1 1 0.002 0.398 1 0.398 0.398 0.398 1 1 SFOVlOOmL2 MPN3/100ml_ MPN/100ml_ MPN/L4 GC6/L PFU7/100ml_ GC/L GC/L GC/L PFU/100ml_ MPN/100ml_ 732 730 729 728 728 714 728 728 728 714 730 l^n SB 201 3 37 2 6 10 0 1 4 3 33 •^ri^^^^^H^^^I ^Q^^ 710 708 707 706 706 692 706 706 706 692 708 fWSs with jsults >MRL 198 3 37 2 6 10 0 1 4 3 32 1SFO = Spore Forming Units 2mL = milliliters 3MPN = Most Probable Number 4L = liters 5RT-qPCR = Reverse Transcription-Polymerase Chain Reaction 6GC = Genomic Copies 7PFU = Plaque Forming Units 8Noroviruses GIA = qPCR analysis of Norovirus genogroup I with RT-qPCR primer set A 9Noroviruses GIB = qPCR analysis of Norovirus genogroup I with RT-qPCR primer set B 10Noroviruses Gil = qPCR analysis of Norovirus genogroup II UCMR 3 Minimum Reporting Levels for Microbiological Contaminants Under UCMR 3 microbe analytical results are reported as "below", "at" or "above" MRL. UCMR 3 MRLs were established based on the capability of the analytical method. It is important to note that microbial contamination can be transient in nature and microbial detections under UCMR 3 should be interpreted in the context of the time samples were collected. However, the presence of any UCMR 3 microbe indicates a potential vulnerability of the PWS to contamination. UCMR 3, October 2015 Page 12 of 12 ------- |