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Lead In Drinking Water

leadinwater.jpgEllis is retained by a number of local school districts to test potable (drinking) water for lead content. 

BACKGROUND - Dissolved lead in drinking water is poisonous.  It can lead to nerve and brain damage, particularly in exposed children.  Lead can enter a school's water supply in one of two ways:

  • Through a contaminated municipal water supply (ala Flint, Michigan); or
  • Through deteriorating lead joints in the building's branch, copper supply lines.  As the joints deteriorate, they can release lead directly into the water.  This is of particular concern in older buildings.

CASE HISTORY – So far, results from testing at different schools have been fairly consistent; lead has been identified in a small percentage of water fountains at each school.  So let's use the first school tested as an example:


METHOD – At every site tested, Ellis collects two representative samples from each water fountain ("source point").  From each source point, the two samples are collected as follows:

  • First draw:  as the fountain is operated, the very first water to come out is directed into a 250 ml jar provided by the testing laboratory.
  • Second draw:  the fountain is then operated (flushed) continuously for 30 seconds.  A second sample is then collected and placed in a similar container.
  • At our example site, 44 fountains were sampled, both first and second draw, for a total of 88 samples collected. 
  • Sampling was conducted between 5 and 7 a.m., before the students arrived.
  • Each sample jar came with a lab-provided liquid preservative.
  • All samples were placed in an insulated container, then hand-delivered directly to an accredited laboratory for analysis.

RESULTS – The EPA has published an "action level" for lead of 15 micrograms lead per liter (15 ug/l).  Here is what we found at the example site:

  • Measured concentrations of lead equaled or exceeded the EPA's action level at 7 of the 44 locations tested – approximately 16 percent.
  • One of those was identified at the municipal supply, where water first enters the school grounds.  The exceedance was found only in the first draw, however. If both the first and second draw had indicated high lead, it might  have indicated a potential problem with the municipal supply.  But no.  As with other locations, flushing the line here reduced lead levels significantly, indicating the problem was likely a leaded joint at the supply point, NOT the overall supply source.  
  • At 6 of the 7 locations where elevated levels were identified, they were observed ONLY in the first draw.  In other words and in every case, flushing the line for 30 seconds reduced lead concentrations significantly.
  • At one location only, lead concentrations for BOTH the first and second draw exceeded the EPA's action level.  But even here, lead concentrations were reduced significantly by flushing the line, from 370 ug/l to 16 ug/l.

SUMMARY -  Again, using the above site as an example:

  • Lead, above the EPA's recommended "action level" of 15 ug/l, was detected in approximately 16 percent of the fountains tested.
  • At each location, flushing the lines for 30 seconds greatly reduced lead concentrations, usually to well below 15 ug/l, often to levels reported as "none detected."

Why is lead in drinking water of concern?  Lead is an ingestion hazard, that is, poisoning by swallowing.  Exposure via contact with surface dust or paint chips MAY sometimes be delayed or reduced by infrequent contact and washing of hands (hygiene).  But because drinking water is ingested directly, exposure to lead poisoning is immediate. 


WHAT WE'VE LEARNED

  • Lead is typically found in drinking water only in a small minority of drinking fountains – typically those fountains that are left idle and unused for long periods.  This allows residual lead at pipe joints to collect and stagnate in the line.
  • Unless initial levels are high, simply flushing (operating the fountain) for as little as 30 seconds typically and significantly reduces lead concentrations, usually to below 15 ppb, the EPA action level.
  • Where lead IS observed in water, the fix is usually also quite simple; inspect the small supply line that services the fountain, and replace it with a section of new line and non-leaded joint.

RECOMMENDATIONS -

  • All schools should have their potable water lines periodically tested for lead.
  • Fountains (source points) with elevated lead levels should be closed to public use until the lines can be inspected and repaired with non-lead joints.
  • Water at the entrance to the school property should also be tested to see if the municipal supply itself is contaminated.
  • Regardless of test results, all parents should arrange for medical testing for blood lead levels in their child.  This process is quick, inexpensive, and useful in assessing whether students' health has been impacted. The test can be arranged privately by parents as part of any normal medical exam. 

Call Ellis at 310 544 1837 with questions or to arrange for testing at your school site.