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Government and People
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
1650 Arch Street
Philadelphia, Pennsylvania 19103-2029
March 24, 2004
Mr. Jerry N. Johnson
Re: Supplemental Sampling Plans
Dear Mr. Johnson:
In accordance with the March 22, 2004 letter from Regional Administrator Donald Welsh to Mr. Robert Bobb, City Administrator, the Environmental Protection Agency (EPA) is providing additional clarifying comments to address the "Additional Sampling" portion of District of Columbia Water and Sewer Authority's (DCWASA) Additional Report on DCWASA Interim Actions. Comments are included in an enclosure to this letter. With these corrections incorporated, EPA concurs with the sampling procedures established for the sampling programs addressed here.
In addition, based on our phone conversation on March 24, 2004, we request, that DCWASA provide further clarification on the data for the sampling of non-lead service customers (i.e., the geographical distribution, raw data, etc.) so that we may determine the adequacy of the remaining residential sampling. We also agreed to work with DCWASA to finalize a protocol to be used for apartment sampling. We expect that both should be accomplished by April 7, 2004. Please contact Karen Johnson or me if you have any questions regarding these comments.
Comments on DC WASA Sampling Plans, as submitted on March 17, 2004
Investigation of Water Quality Data for Residential Customers:
EPA supports the investigation of homes with non-lead service lines using test pits, EPA suggests that DCWASA include some locations listed as "unknown" or indicate what DCWASA plans to do to accurately characterize the "unknown" service line materials into a definitive category (copper, brass, etc.). EPA reserves determination about the underlying data on which the tables were based. DCWASA should ensure that the locations selected for test pits were sampled using the correct protocol.
All Other Sampling:
DCWASA indicates that it will supply the results of sampling to the facility sampled, For the protocols using 250 milliliter samples, EPA recommends using an Action Level of 20 parts per billion (ppb) established in EPA's Guidance "Lead in Drinking Water in Schools and Nonresidential Buildings" (April 1994).
Apartment Building Sampling:,
Agency roles and responsibilities
The building management should know there maybe a need for follow up sampling and or repairs, if there is an issue with the plumbing fixtures.
Add a bullet: The preferred sample location in a given apartment is the kitchen faucet.
Sampling Protocol: The protocol is incorrect. The protocol should be the same for schools and other buildings at non-water cooler locations. The 10-minute flush before the second sample will not yield data that can easily be interpreted. We suggest you take two 250 ml. samples, the first draw and a 30 sec. flush so you are sampling the fixtures and just behind the wall in the apartments. If DCWASA wants to take a 10-minute flush sample from the first apartment closest to the main (bottom floor) that is acceptable as a third sample. Sequential 10-minute samples throughout the apartment building will not likely result in meaningful data, and would present a challenge in determining where the water is drawn from or what follow-up to take if you have elevated sample results.
Sampling in Schools:
Delete the introduction after 2nd paragraph, as the sampling did not follow the accepted protocol for school sampling and there are limitations on the results/conclusions, except for the first draw samples results.
Agency Roles and Responsibilities:
Inventory of Drinking Water Outlets in Schools
Under Non Water Cooler Flushing: #5 Start to flush at the farthest outlet from the main, e.g. the farthest wing where the preschool is located or the top floor, etc. Open the cold water tap full. If the water is tepid, flush until there is a significant temperature change, no matter how long the time is. Each successive tap is then opened for 10 minutes or until the temperature change is felt.
Under Non Water Cooler Sampling: #2 After taking the 1st draw sample, there should be a step inserted to "cap the sample and mark the bottle as the 1st draw before flushing" for the second sample.
Under Water Cooler Flushing: Make sure you hear the pump running for 10-15 minutes after you have drained the reservoir to make sure it is filled with fresh water.
Under Water Cooler Sampling: #2 After taking the 1st draw sample, there should be a step inserted to "cap the sample and mark the bottle as the 1st draw before flushing" for the second sample.
Sampling in Charter and Independent Schools:
Roles and Responsibilities
The schools should know what to do with the results when they are received. The EPA guidance spells out additional sampling to pinpoint the source of any problems. The schools should be told upfront they will be responsible for repair/replacement of fixtures and any pipes which are problems.
Under the bullet "Use cold water for drinking. ...Boiling water does not remove lead, it concentrates it."
Under the bullet for flushing each day, expand the flushing directions as follows to clarify.
"..you should consider flushing each fountain or sink which children are drinking water for ten minutes before the start of each day, This can be accomplished by going to the sink farthest from the street and taming on the cold tap and letting it run until there is a significant temperature change. Work back through the building opening each additional tap until you feel the temperature change to get all remaining water out of the riser."
Under the School Survey forms:
#23 add nurses sink to the list of places to sample.
#24 Add any other uses with sinks or fountains used for drinking, like kindergarten or preschool snack preparation, rooms with sinks where special education or disabled children's water bottle's are filled, etc.
Inventory of Drinking Water Outlets, Sampling Procedures,
and Guidelines for Sample Bottle Labeling
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