1. NSF International The Public Health and Safety Company™
NSF/ANSI Standard 53
Lead pH 8.5 Testing Update
Live Safer™

2. Protocol Origins Current Lead pH 8.5 protocol adopted in 2007.
Laboratories conducting tests under old protocol were internally consistent, but inconsistent between laboratories.
Particulate lead was determined to be the primary cause of the inconsistency.
Literature search was performed to establish levels of particulate in distribution systems.
Two validation studies were conducted by many laboratories to develop and finalize protocol.

3. Occurrence of Particulate Lead
Literature search was conducted with the goal of obtaining references that would clarify the existence of particulate lead and provide data to guide the Task Group in setting an influent requirement.
28 citations were found that contained relevant information about the formation and presence of particulate lead in public water supplies.
7 citations contained field data on the occurrence of particulate lead in real world water distribution systems.

4. Occurrence of Particulate Lead
No references were found that refuted the presence of particulate lead in drinking water systems.
Particulate lead was found in many different water chemistries, low and high pH.
Levels measured varied significantly based on when and how a sample was collected.
Size distribution varied significantly between samples.

5. Field Data – Ratio of Particulate to Total Lead
Lead Form
Mean
Std Dev
90th Percentile
Total Lead (ppb) 28 67 89
Particulate Lead (ppb) 21 61 68
Percent Particulate Lead 59 35
100
Data set consists of 101 data points reported from 5 references.
Some data points are averages of several samples taken in a study (over 200 individual samples).
Data represents 22 different distribution systems (10 from UK, 12 from USA)

6. Field Data – Variation due to Sample Conditions
Initial Conditions
Stable Conditions
Test Condition
Total Lead (ppb)
Particulate Lead (ppb)
Rapid Valve
1800
1600 12 7
Slow Valve
670
500 4
0.5
Low Flow
1300
1100 10 2
High Flow
4500
4300 5
Lead Service Line from New Orleans, LA.

7. Field Data – Variation from Single Source
Lead Size Range
Average Percent
Std Dev
Upper 90th Percentile
Lower 90th Percentile
> 1 um 49 26 94 18
< 1 um 51 82 6
Data from 31 samples collected from one water source.
Range of measurements were 0 to 100%.
Range of percent of lead particulate from 0 to 93% of total lead.

8. NSF Lead pH 8.5 Water Preparation
Average Total Particulate is 34%.
86% of Total Particulate values fall within the 20 – 40% range (average range required in Std).
Average Fine Particulate is 68%.
86% of all tanks prepared meet Standard requirements.
Primary reasons for missing water preparation requirements are:
1. Equipment requires cleaning
2. Technician error

11. Recommendations for Lead Protocol Improvement
The filtration of the sample to determine fine particulate must be performed at a rate that exceeds 1ml/second. Otherwise fine particulate values are under reported.
Explicit instructions on adjusting soluble and insoluble additions to hit challenge targets.
Additional language urging the need to follow all requirements precisely, including listing some of the critical elements.

12. Thank You for Your Attention. Any Further Discussion?