# Presentation: 692816

## The Radionuclides Rule

- Monitoring, Compliance, and Substitution

## Overview

- Monitoring
- Frequency
- Initial
- Routine/Reduced
- Increased
- Location
- Compliance Calculations
- Substitution

- The focus is on Gross Alpha, R-226, R-228, and Uranium
- But. . .
- will talk about Beta and Photon Emitters!

**Notes:**
This presentation includes information on:
Monitoring for radionuclides including initial, routine/reduced, and increased monitoring frequencies;
Monitoring locations;
Determining compliance for gross alpha, radium-226/228, uranium and gross beta; and, 
Substitution of gross alpha for radium and uranium.
Examples of compliance determinations and substituions are also provided.
The focus of the presentation is on gross alpha, radium-226/228, uranium.  The occurrence of beta and photo emitters in drinking water is rare.  However, since these emitters are regulated by the Radionuclides Rule, summary information is provided. 

## Standards

| Contaminant | MCL | Detection Limit |
| --- | --- | --- |
| Gross Alpha | 15 pCi/L | 3pCi/L |
| Combined 
R-226/228 | 5 pCi/L | 1pCi/L |
|  |  | 1pCi/L |
| Uranium | 30 ug/L | TBD |
| Gross beta | 4 mrem/yr
168 individual emitters may be used to calculate compliance | 4 |

## Monitoring Frequency

- Initial
- Routine/Reduced
- Increased
- Beta and Photon Emitters

**Notes:**
This section of the presents the initial, routine/reduced, and increased monitoring frequencies, first for gross alpha, radium-226/228 and uranium, and then for beta and photon emitters.  
The Radionuclides Rule made monitoring for gross alpha, radium-226/228 and uranium consistent with the Standardized Monitoring Framework and monitoring for other regulated inorganic contaminants. 
Also included is information on special considerations (e.g., the state can require the system to take confirmation samples), and state flexibilities (e.g., using grandfathered data to satisfy the initial monitoring requirements).  

## Initial MonitoringGross Alpha, R-226, R-228, & Uranium 

- Complete by December 31, 2007
- Establish compliance with 4 consecutive quarterly samples at each entry point
- Compliance based on running annual average (RAA) of samples
- First 2 initial samples < detection limit
-  State can waive last 2 quarters of sampling

**Notes:**
Systems must complete their initial monitoring by December 31, 2007.  
EPA extended the initial compliance monitoring period in the final Radionuclides Rule so that the first compliance cycle is consistent with the other IOCs under the Standardized Monitoring Framework. 
Compliance must be based on the running annual average of the collected samples.
Once the system satisfies the initial monitoring requirements, the Primacy Agency can determine the future monitoring schedule for each contaminant at each entry point. 
Under certain circumstances, Grandfathered data can also be used to determine the future monitoring schedule.  
The Primacy Agency may waive the final 2 quarters of initial monitoring for an entry point if the results from the first 2 quarters are below the detection limit.  
The Primacy Agency cannot waive the monitoring requirements for beta particle or photon emitters if a system has been designated as vulnerable or contaminated. 

## Routine/Reduced Monitoring Gross Alpha, R-226, R-228, & Uranium 

- Determine frequency for each contaminant at each entry point
- After initial monitoring period
- Use the RAA or Grandfathered data from each entry point to determine future monitoring frequency
- Routine monitoring
- Based on previous analytical results
- An increase in contaminant concentration may increase monitoring frequency for that contaminant

**Notes:**
States must use the RAA from the initial monitoring period or grandfathered data to determine the future monitoring schedule. 
A system can stay on a reduced monitoring schedule as long as the results support the schedule.  
How often a system will have to monitor will depend on the concentration of the contaminant for the most recent monitoring result. 
For example, if a system takes a sample every 6 years and the latest result is below the detection limit,  the state can reduce the monitoring for that contaminant at that entry point to 1 sample every 9 years.  Conversely, if the system taking one sample every 6 years has a result greater than 1⁄2 the MCL but less than the MCL, the system must begin monitoring once every 3 years. 

## For Gross Alpha, R-226, R-228, & Uranium, if the Result at an Entry Point is. . .

| < detection limit | 1 sample every 9 years  |
| --- | --- |
| > detection limit and < one-half MCL | 1 sample every 6 years |
| > one-half MCL < the MCL | 1 sample every 3 years |
| > MCL | 1 sample per quarter until results from 4 consecutive quarters < MCL |

**Notes:**
A system can stay on a reduced monitoring schedule as long as the results support the schedule.  
For example, if a system takes a sample every 3 years and the latest result is above the detection limit less than half the MCL,  the state can reduce the monitoring for that contaminant at that entry point to 1 sample every 6 years.  Conversely, if a system is taking a sample once every 9 years and the latest result is greater than 1⁄2 the MCL but less than the MCL, the system must begin monitoring once every 3 years. 
A result above the MCL means the system must begin quarterly monitoring, and continue taking samples every quarter until 4 consecutive quarterly samples are at or below the MCL and the state has determined that the entry point is reliably and consistently below the MCL.   
Systems are only required to conduct quarterly monitoring at the entry point at which the sample was collected and for the specific contaminant that triggered the system into the increased monitoring frequency.

## Increased Monitoring  Gross Alpha, R-226, R-228, & Uranium 

- MCL Exceedance?
- Must begin quarterly sampling
- Continue until 4 consecutive quarterly samples are < MCL
- If a system fails to monitor in consecutive quarters:
- Running annual average (RAA) is based on the number of samples collected
- EPA recommends:
- Collect final sample as soon as possible, or
- Collect sample in missed quarter, the following year

**Notes:**
Systems that sample once a year or less and have and entry point with a result above an MCL, will be put on an increased monitoring schedule. 
If the running annual average (RAA) of one year of quarterly samples is greater than the MCL, then the system is in violation of the MCL. 
If an entry point sampling result is four times the MCL or if a sampling result causes the RAA to exceed the MCL, the SYSTEM is in violation of the MCL.  
The system must continue quarterly monitoring at that entry point until 4 consecutive quarters are at or below the MCL and the state determines that the monitoring results are reliably and consistently below the MCL. 
If a system misses a sample, the RAA is based on the number of samples collected.  
States may require the system to either collect the fourth sample as soon as possible or collect the sample the following year in the quarter that was missed.

## Special Considerations

- States can require confirmation samples
- New systems & systems using a new source
- Conduct initial monitoring for new source
- Initial results serve as “occurrence profile”
- Begin in first quarter after initiating use

## State Flexibilities

- Determine a representative sampling point
- Waive last 2 quarters of initial monitoring
- Require system to take “missed” quarterly samples either as soon as possible, or the same quarter the next year
- Compositing
- Grandfathering

**Notes:**
Representative Sampling Point. Systems do not have to sample at each EPTDS to satisfy the monitoring requirements if:
The Primacy Agency has determined that conditions make another sampling point more representative of each source (40 CFR §141.26(a)(1)(i)) or, the interconnection of systems justifies treating them as a single system for monitoring purposes (i.e. consecutive PWSs) (40 CFR §141.29).
Waiving last 2 quarters of Initial Monitoring. The Primacy Agency may waive the final 2 quarters of initial monitoring for an entry point if the results from the first 2 quarters are below the detection limit.  
The Primacy Agency cannot waive the monitoring requirements for beta particle or photon emitters if a system has been designated as vulnerable or contaminated. 
Compositing. Systems can composite up to 4 consecutive quarterly samples from a single entry point (i.e., temporal compositing) if the analysis is done within a year of the first sample. The Rule prohibits spatial compositing.
The laboratory that analyzes the samples must use a method with a detection limit of 1/5th the MCL (40 CFR §141.26(a)(4)). 
Can require additional quarterly samples if composite is >1/2 MCL
Grandfathering. The Primacy Agency may allow data collected between 6/00 - 12/08/03 to satisfy the initial monitoring requirements if:
Samples were collected at each entry point; 
The system has 1 entry point & samples were collected in the distribution system; or,
The system has multiple entry points & samples were collected in the distribution system & the Primacy Agency makes a written finding that the data are representative of all entry points; and,
The Primacy Agency has determined through examination of appropriate historical data and monitoring data taken between June 2000 and December 8, 2003, that each entry point is expected to be in compliance. (40 CFR §141.26(a)(2)(ii)).  
System may not use grandfathered data to satisfy the monitoring requirements for beta and photon emitters. 

## Routine Monitoring Beta and Photon Emitters

**Contaminated Systems**

**Vulnerable Systems**

- Gross Beta
- Iodine - 131

- Gross     Beta

**Quarterly**

- Tritium
- Strontium-90

**Annually**

**Notes:**
States should use existing vulnerability assessments (required under the 1975 Radionuclides Rule) to notify systems of their status (i.e., vulnerable or contaminated) and of the monitoring requirements.  
EPA is encouraging States to re-evaluate a system’s vulnerability to beta particle and photon radioactivity sources when conducting a system’s source water assessment and to provide immediate notification to those systems that have been deemed vulnerable or contaminated.
Vulnerable systems must collect quarterly samples for beta emitters and annual samples for tritium and strontium-90 at each EPTDS (40 CFR  141.26(b)(1)). Sampling must begin during the quarter following the quarter in which the system is notified by the Primacy Agency.  
Systems designated by the Primacy Agency as utilizing waters contaminated by effluents from nuclear facilities must also collect quarterly samples for beta emitters and iodine-131, and annual samples for tritium and strontium-90 at each EPTDS (40 CFR  141.26(b)(2)).  More frequent monitoring is required if iodine-131 is found in finished water (40 CFR  141.26(b)(2)(ii)).  Sampling must begin during the quarter following the quarter in which the system is notified by the Primacy Agency. 
Quarterly monitoring for gross bets is based on the analysis of monthly samples or the analysis of a three month composite of samples. (40 CFR  141.26(b)(2)(i)).  
For iodine-131, systems must composite five consecutive daily samples. (40 CFR  141.26(b)(2)(ii)).  
For the annual monitoring requirements for tritium and strontium-90, samples must be collected quarterly and analyzed or composited and analyzed (40 CFR  141.26(b)(2)(iii)).  In all cases, laboratories are responsible for composting the samples prior to analysis. 

## Reduced MonitoringBeta and Photon Emitters

**Notes:**
A Primacy Agency may allow a system to reduce the frequency of monitoring to once every three years if:
In a vulnerable system, the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity has a running annual average (computed quarterly) less than or equal to 50 pCi/L (40 CFR § 141.26(b)(1)(i)).
In a system designated by the Primacy Agency as utilizing waters contaminated by effluents from nuclear facilities, the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity has a running annual average (computed quarterly) less than or equal to 15pCi/L (40 CFR § 141.26(b)(2)(iv)).

## Increased MonitoringBeta and Photon Emitters

- Exceedance of Gross Beta Minus Potassium-40
- Speciate for most likely emitters
- MCL violation
- Monthly Monitoring

**Notes:**
A system that exceeds the gross beta particle activity screening level, (excluding the naturally occurring potassium-40) must further analyze the sample for the major radioactive constituents (40 CFR §141.26(b)(5)).  
The system must determine compliance with the MCLs for beta particle and photon radioactivity by using the “sum of the fractions” calculation (40 CFR §141.66(d)(2)). 
A Primacy Agency should require a system to speciate the sample for the most likely emitters associated with the nearby source.
If the results show an MCL violation for any of the constituents, the system must conduct monthly monitoring at any sampling point that exceeds the MCL beginning the month after the exceedance occurs.  
A system can resume quarterly monitoring if the rolling average of three months of samples is at or below the MCL (40 CFR §141.26(b)(6)).

## Monitoring Locations

## Monitoring Locations

- Sample for each contaminant at each entry point
- State can determine if another sampling point is more representative
- Sample during normal operating conditions
- For seasonal systems, water should represent all sources in use

**Notes:**
Systems must monitor at each entry point in the distribution system. 
The ideal initial monitoring scenario involves a system collecting 4 consecutive quarterly samples at each entry point. If a system misses a sample, States may require the system to either collect the fourth sample as soon as possible or collect the sample the following year in the quarter that was missed.  
Systems do not have to sample at each entry point to satisfy the monitoring requirements if:
The Primacy Agency has determined that conditions make another sampling point more representative of each source (40 CFR §141.26(a)(1)(i)).
The Primacy Agency has modified the monitoring requirements of a PWS that supplies water to one or more other PWSs and the interconnection of the systems justifies treating them as a single system for monitoring purposes (i.e. consecutive PWSs) (40 CFR §141.29).  
Systems that use an intermittent source of supply (e.g., a supply affected by seasonal variation) or use more than one source and the sources are combined before distribution, must sample at an entry point when water is representative of all the sources being used. 

## Determining Compliance

- Running Annual Average
- Sum of the Fractions
- Reliably and Consistently
- Return to Compliance

## Calculating Compliance Gross Alpha, R-226, R-228, & Uranium 

- Compliance must be determined for each contaminant at each entry point
- If one entry point is in violation of an MCL the system is in violation of the MCL

## Systems Monitoring Less Than Once Per Year

- > MCL at any entry point triggers quarterly monitoring at that entry point
- Compliance based on RAA of 4 consecutive quarterly samples
- Quarterly sampling continues until results from 4 consecutive quarters are < MCL
-  An increase in contaminant concentration may increase monitoring frequency for that contaminant

**Notes:**
A system is not in violation of an MCL unless the running annual average is greater than the MCL, one sampling result is 4 times the MCL, or any one sample result would cause the running annual average to be exceeded.     

## Systems Monitoring More Than Once Per Year

- RAA at each entry point determines compliance
- If RAA is > MCL, system is out of compliance
- If RAA is < MCL, system is in compliance
- If a system fails to monitor in consecutive quarters
- RAA is based on the number of samples collected

## Violations

- One sample result is 4 times the MCL
- One sample result causes RAA to exceed MCL
- RAA exceeds MCL

## Special Considerations

- Systems monitor separately for Ra-226 and Ra-228
- Compliance is based on the combined Ra-226 and Ra-228 results
- Any required confirmation samples must be averaged with original analytical result
- If sample is < detection limit
- Use ‘zero’ in RAA calculation
- Exception: gross alpha substitutions

## Reliably & Consistently

- Primacy Agency has sufficient knowledge to predict that MCL will not be exceeded
- Ground water systems must take a minimum of 2 quarterly samples
- Surface water systems must take a minimum of 4 quarterly samples

- Need not be consecutive quarters!
- State can reduce monitoring to once every three years

**Notes:**
To make a “reliably and consistently determination,” States should examine, among other things:
The quality of data
The amount of data
The length of time covered by the data
Whether there are wide variations in the data?
Whether there are wide variations in results?
The Primacy Agency can allow a system to take the minimum number of quarterly samples in non-consecutive quarters. 
NOTE: This differs from the requirement for a compliance determination because compliance is based on the total number of samples collected.

## Return to Compliance

- State has made a reliably and consistently determination
- Ground water systems have taken minimum of 2 consecutive quarterly samples
- Surface water system have taken a minimum of 4 consecutive quarterly samples
- All sampling results <  MCL
- System is monitoring and reporting in accordance with the criteria for compliance

## Compliance DeterminationBeta and Photon Emitters

- Sum of the fractions
- 4 millirems/year
- “Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air or Water for Occupational Exposure”

**Notes:**
The Radionuclides Rule uses a “sum-of-the-fractions” method to determine whether a system is in compliance with the MCL for beta particle and photon radioactivity (40 CFR §141.66(d)).  
 The sum of the beta and photon emitters shall not exceed 4 millirems/year (40 CFR §141.66(d)(2)). 
While the measure used to determine risk is “millirems,” contaminants are analyzed in the “pCi/L”. Therefore, to determine compliance, each beta and photon emitter must be converted from pCi/L to millirems using the conversion tables listed in “Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air or Water for Occupational Exposure” (NBS Handbook 69 as amended August, 1963, U.S. Department of Commerce).  
For each emitter that is detected by the laboratory, the system must divide the pCi/L found in the sample by the value in the conversion tables.  This provides a fraction of how much the particular beta or photon emitter is providing towards the maximum of 4 mrem/yr for all of the beta photon emitters. 

## Substitution

- Using Gross Alpha for R-226
- Using Gross Alpha for Uranium

**Notes:**
Determining compliance and future monitoring frequencies for the regulated radionculides is complex in part, because of the relationship of the analytes. 
The alpha emitters, radium-226, and uranium contibute to gross alpha activity. 
Because of this relationship, gross alpha particle activity results can be used to determine the monitoring frquency for gross alpha, radium-226, and uranium.  

## Gross Alpha For R-226

- If gross alpha is < 3 pCi/L (detection limit)
- Use 1.5 pCi/L for R-226 value
- Combine with R-228 result to determine monitoring frequency for R-226/228
- Gross alpha is > 3 pCi/L but < 5 pCi/L
- Use whole gross alpha result for R-226 value
- Combine with R-228 result to determine monitoring frequency for R-226/228

**Notes:**
When substituting gross alpha for radium-226:
If the gross alpha result is less than the detection limit (<3 pCi/L) use 1⁄2 the detection limit (1.5 pCi/L) and add it to the radium-228 result.  This combined value is used to determine radium-226 compliance and future monitoring frequency.
If the gross alpha result is greater than the detection limit (> 3 pCi/L), combine the whole gross alpha result with the redium-228 result to determine compliance and future monitoring frequency.   
EPA is recommending that systems substitute gross alpha for radium-226 only if previous gross alpha results are less than the gross alpha detection limit (i.e. 3pCi/L).  
With a gross alpha result at or above 3 pCi/L, the system risk violating the combined radium-226/228 MCL of 5 pCi/L and therefore should monitor individually for radium-226/228.   

## Gross Alpha For R-226

- Systems substituting gross alpha for R-226 cannot move to 9 year routine monitoring schedule for R-226/228
- Can’t confirm that radium-226 is below its detection limit (1 pCi/L)
- Account for analytical error in gross alpha result
- Confidence interval of 95%
- 1.65s, where s = standard deviation of net counting rate of sample

**Notes:**
While the number of samples the system is required to take is reduced, a system that submits only gross alpha particle activity analytical results and does not sample for radium-226 may be required, under the reduced monitoring requirements, to sample once every 3 or 6 years rather than once every 9 years. 
Systems that only submit gross alpha particle activity analytical results and do not sample for radium-226 individually may:
not be allowed to move to a reduced monitoring frequency of one sample every nine years. This is due to the fact that the detection limit for gross alpha (3pCi/L) will not allow you to confirm that radium-226 is below the respective detection limit as measured individually (1pCi/L). 
be at risk for violating the combined radium-226/228 MCL of 5pCi/L.  

## If a system substitutes Gross Alpha for R-226. . .

| And the result is: | The Primacy Agency must: |
| --- | --- |
| < 3 pCi/L
(Detection Limit) | Use 1.5 pCi/L + R-228 to determine compliance with R-226/228 MCL  |
|  | Determine monitoring frequency as quarterly or once every 3 or 6 years |
| > 3 pCi/L 
but 
< 5 pCi/L | Use whole gross alpha result 
+ R-228 to determine compliance with R-226/228 MCL  |
|  | Determine monitoring frequency as quarterly or once every 3 years |

**Notes:**
If the gross alpha particle activity result is:
 less than detection, 1⁄2 the detection limit (i.e. 1.5pCi/L) is used for radium-226 and is added to the radium-228 activity. 
above the detection limit, compliance and future monitoring frequency is determined using the whole gross alpha result. 

## Gross Alpha & Uranium

- Systems with gross alpha _**<**_ 15 pCi/L
- Can substitute for uranium
- Account for analytical error in gross alpha result

- Systems with gross alpha **>**15 pCi/L
- Must monitor for uranium and report both mass and activity to the state
- State must convert uranium mass to activity
- Can subtract uranium activity from gross alpha
- This “net alpha” result can be used to determine compliance with gross alpha MCL

**Notes:**
A gross alpha particle activity measurement may be substituted for the required uranium measurement if the gross alpha particle activity is less than or equal to 15 pCi/L.
If the gross alpha particle activity is greater than 15 pCi/L, the system must monitor for uranium. 
The uranium analysis will serve a dual purpose for systems with entry points that have high levels of gross alpha activity. 
First, the uranium activity can be subtracted from gross alpha to determine compliance with an entry point’s gross alpha MCL.  
The term “net alpha” is being used to describe gross alpha minus uranium.  
Second, the results can be used to determine an entry point’s future monitoring frequency for uranium.
It is a three step process to determine compliance with the gross alpha MCL in systems with a gross alpha result > 15 PCi/L.
Step 1. Unless the laboratory reports uranium results in activity, the state must convert the uranium mass measurement to activity by using a conversion factor of 0.67 pCi/g; 
Uranium activity can be converted to mass by multiplying the uranium activity by 1.49 pCi/g. 
Step 2.  Subtract the uranium activity from the gross alpha activity.
Step 3.  Use the “net” result to determine compliance and future monitoring frequency for gross alpha.  

## Slide 30

**Notes:**
States may subtract the uranium activity from the gross alpha particle activity to determine compliance with the gross alpha MCL, which is referred as “net alpha” (i.e. gross alpha particle activity minus the uranium activity).
The Primacy Agency is responsible for subtracting the uranium activity from the gross alpha particle activity to determine compliance with the “net alpha” MCL.
At this time, conversion factors that have been calculated by assessing the uranium mass to activity ratios for individual systems may not be used (40 CFR §141.25 Footnote 12).  

## If a system substitutes Gross Alpha for Uranium. . . 

- Assume all of gross alpha = uranium

- Require the system to collect uranium samples

- Use mass to activity ratio of 1:1

- The Primacy Agency must:

- >15 pCi/L

-  15 pCi/L

- And the result is:

**Notes:**
A gross alpha particle activity measurement may be substituted for the required uranium measurement if the gross alpha particle activity is less than or equal to 15 pCi/L.  
States must assume all of the gross alpha activity is due to uranium and a mass to activity ratio of 1:1 must be used.  
If the gross alpha particle activity is greater than 15 pCi/L, then samples must be collected for uranium (40 CFR 141.26(a)(5)).

## Examples

## Initial Monitoring System takes 4 quarterly samples for Gross Alpha in 2005 (MCL 15 pCi/L) 

**Result**

**Date**

**13**

**Jul 05**

**16**

**Oct 05**

**12**

**Apr 05**

**16**

**Initial Result**

**Jan. 05**

**15 **

**Confirmation**

**Average = 16 pCi/L**

_**16 + 12 + 13 + 16**_** = 14 pCi/L**
**	****4**

**Notes:**
To satisfy the initial monitoring requirements, this system takes 4 consecutive quarterly samples in 2005 for gross alpha from its one entry point.  Because the result of the initial sample is greater than the MCL, the state requires the system to take a confirmation sample.
At the end of the year, the state calculates the running annual average (using the average of the initial and confirmation sample as the result for quarter 1).
With a RAA of 14 pCi/L, the system is in compliance with the gross alpha MCL. 

## Routine Monitoring Schedule

- Initial monitoring results = 14 pCi/L
-  > one-half MCL < the MCL
- Routine gross alpha sample required by 2008
- One sample every 3 years

**Notes:**
The RAA for gross alpha is 14 pCi/L.  
Because the running annual average is >1/2 the MCL but < the MCL, the system is required to take its next sample in three years, or 2008.   

## Reduced Monitoring Schedule

- Routine sample in 2008 = 7 pCi/L
- > detection limit and < one-half MCL
- Next routine sample 2014
- One sample every 6 years

**Notes:**
The system takes its routine sample in 2008 with a result of 7 pCi/L.  
Because the result is > than the detection limit and < 1⁄2 the MCL the system does not have to sample for 6 years for gross alpha at this entry point.  The next sample is due in 2014.  

## Gross alpha result that causes RAA to exceed MCL 

_**33 + 31 + 0 + 0**_** = 16 pCi/L**
**4**

**Average = 33 pCi/L**

**Notes:**
To satisfy the initial monitoring requirements, this system begins quarterly sampling  in 2004. 
Because the result of the initial sample is greater than the MCL, the state requires the system to take a confirmation sample.
The state calculates the running annual average after the system takes its sample in the second quarter.  
This system has violated the gross alpha MCL after the second quarter.  Even if the state assumes the next two quarter’s results are non-detects, the running annual average will still be over the gross alpha MCL.

## Gross Alpha for R-226

- Substitute 1.5 pCi/L for < detect gross alpha
- Add to Ra-228 result
- Determine Ra-226/228 monitoring frequency
- MCL = 5 pCi/L
- 5 pCi/L  3.5 >2.5 pCi/L
- 1 sample every 3 years

**Value**

**Sample**

-  2 pCi/L

- Ra-228

-  < Detect

- Gross Alpha

- 3.5 pCi/L

- Total
- Ra-226/228

**Notes:**
This system monitors for gross alpha at its one entry point.  The results are less than detect and the system chooses to substitute the gross alpha result for radium-226.
Because the gross alpha result is less than the detection limit, the system subsittutes 1⁄2 the detection limit (1.5 pCi/L) for the radium-226 result.
1.5 pCi/L gets added to the system’s radium-228 result of 2 pCi/L.
The combined radium-226/228 of 3.5 pCi/L means the system must sample for radium-226/228 once every three years (5 pCi/L  3.5 >2.5 pCi/L).

## Gross Alpha and Uranium

- Convert mass to activity
- 22 ug/L x 0.67 pCi/ug = 15 pCi/L
- Subtract activity from gross alpha result
- 24 pCi/L -  15 pCi/L = 9 pCi/L
- Take uranium sample in the next 3 year compliance period
- >1⁄2 the MCL but _<_MCL
- Take gross alpha sample in the next 3 year compliance period
- “net alpha” value of 9 pCi/L is >1⁄2 the MCL but _<_MCL

**Notes:**
The uranium mass was converted by multiplying the measured value by 0.67 pCi/g (i.e. 21 g/L x 0.67 pCi/g = 14 pCi/L).  The converted uranium activity (14 pCi/L) was subtracted from the measured gross alpha (24 pCi/L) yielding 10 pCi/L “net alpha”.  The “net alpha” value was used to determine compliance with the gross alpha MCL (15 pCi/L).
The system is in compliance with the uranium MCL and is required to collect a uranium sample in the next 3 year compliance period (i.e., 1 sample every three years for results >1⁄2 the MCL but MCL).
The system is in compliance with the gross alpha MCL and is required to collect another gross alpha sample in the next 3 year compliance period (i.e., the calculated “net alpha” value of 10 pCi/L is >1⁄2 the MCL but MCL).

## Sum of the Fractions

- Step 1: Convert lab analysis (pCi/L) into pCi/4mrem using conversion table
- Step 2: Calculate Fraction
- Step 3: Calculate Total mrem

**Notes:**
The Radionuclides Rule uses a “sum-of-the-fractions” method to determine whether a system is in compliance with the MCL for beta particle and photon radioactivity (40 CFR §141.66(d)).  
While the measure used to determine risk is “millirems,” contaminants are analyzed in the “pCi/L”. Therefore, to determine compliance, each beta and photon emitter must be converted from pCi/L to millirems using the conversion tables listed in “Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air or Water for Occupational Exposure” (NBS Handbook 69 as amended August, 1963, U.S. Department of Commerce).  
For each emitter that is detected by the laboratory, the system must divide the pCi/L found in the sample by the value in the conversion tables.  This provides a fraction of how much the particular beta or photon emitter is providing towards the maximum of 4 mrem/yr for all of the beta photon emitters. 

## Sum of the Fractions

**1.35  x  4mrem  =  5.4**

**SUM OF THE FRACTIONS**

- 0.7

- 3

- 2

**I-131**

- 0.5

- 8

- 4

**Sr-90**

- 0.150

- 200

- 30

**Cs-137**

**Calculate Fraction**

**Conversion from table (pCi/4mrem)**

**Lab Analysis (pCi/L)**

**Emitter**

**Notes:**
 The sum of the beta and photon emitters shall not exceed 4 millirems/year (40 CFR §141.66(d)(2)). 

## Is combined Ra-226/228  

**> 1 pCi/L and **_**<**_** 2.5 pCi/L?**

**Is GA < 3 pCi/L?**

**Substitute 1.5 pCi/L for Ra-226 and add to Ra-228**

**Monitor R-226/228 once in 6 years**

**Is combined Ra-226/228  **
**> 2.5 pCi/L and **_**<**_** 5 pCi/L?**

**Is GA **_**>**_** 3 pCi/L and < 5 pCi/L?**

**Substitute whole GA result for Ra-226 and add to Ra-228**

**Monitor GA once in 9 years**

**Monitor GA once in 6 years**

**YES**

**YES**

**Is combined Ra-226/228 > 5 pCi/L?**

**NO**

**NO**

**Monitor R-226/228 once in 3 years**

**Monitor R-226/228 quarterly**

**YES**

**YES**

**YES**

**NO**

**NO**

## Is GA > 15 pCi/L?

**Substitute whole GA result for U using 1:1 (mass:activity)**

**Collect U**

**Monitor GA **
**once in 6 years**

**Is GA > 7.5 pCi/L and **_**<**_** 15 pCi/L?**

**Monitor GA once in 3 years **

**Monitor U 1 in 6**

**Is GA **_**>**_** 5 pCi/L and **_**<**_** 7.5 pCi/L?**

**YES**

**NO**

**NO**

**YES**

**Multiply U result by 0.67 pCi/L to determine activity**

**Subtract U activity from GA**

**Is GA < 3 pCi/L?**

**Is GA **_**<**_** 7.5 pCi/L and **_**>**_** 3 pCi/L?**

**Is GA **_**<**_** 15 pCi/L and > 7.5 pCi/L?**

**Monitor quarterly**

**YES**

**Is U < 1 ug/L?**

**Substitute whole GA result for U using 1:1 (mass:activity)**

**Is U **_**<**_** 15 ug/L and **_**>**_** 1 ug/L?**

**Is U **_**<**_** 30 ug/L and > 15 ug/L?**

**Monitor once in 6 years**

**Monitor once in 9 years**

**Monitor once in 3 years**

**Is U > 30 ug/L?**

**YES**

**NO**

**NO**

**NO**

**YES**

**YES**

**YES**

**YES**

**YES**

**YES**

**NO**

**NO**