[Dialogue] Salmon: Lead butts?

Sun Mar 18 21:21:57 EDT 2012

Lead levels? 
    Ever live in 5th City Chicago or on North Sheridan? Is it any wonder most of us now have trouble "getting the lead out" of our butts? 
    Bill Salmon

----- Original Message ----- 
  From: Ken Fisher 
  To: Colleague Dialogue ; Order Ecumenical Community 
  Sent: Sunday, March 18, 2012 7:42 PM
  Subject: [Oe List ...] Bruce Lanphear - Ottawa Citizen - Sun. Mar. 18th - p.3

  http://www.ottawacitizen.com/health/Danger+dust/6320223/story.html

  Danger in the dust

  A Health Canada survey finds elevated levels of lead in some homes built after 1980. But while provinces set guidelines for lead levels in soil, Canada has no rules about lead levels in house dust. Becky Rynor reports

  BY BECKY RYNOR, OTTAWA CITIZEN MARCH 18, 2012 A Health Canada review has found elevated levels of lead residue in the dust found in the nooks and crannies of 10 per cent of homes built after 1980.

  That discovery has prompted a chief scientist with the federal department to say "the line is blurring" on which homes are more likely to have such elevated levels of lead in dust. And the finding is renewing calls from experts for tough limits on blood-lead exposure.

  "Everybody expects older homes to be associated with elevated lead in the dust because of the extensive use of lead especially previous to World War II," says Dr. Pat Rasmussen, the principal investigator on the Canadian House Dust Study, which examined samples in urban, residential communities. "The good news was that we found a lot of older homes that did not have elevated lead. That said to me that renovations over the decades have improved the situation," she says. "The bad news is that a significant number of homes built after 1980 - about 10 per cent - had elevated lead in them."

  Rasmussen attributes those higher levels to consumer products such as solder and polyvinyl chloride. "In consumer products it's not only in the metallic form, it's in pigments, it's in plastics as a drying agent, as a stabilizer, as an extender. These are all practical uses of lead compounds that are not banned."

  The study, which considered a concentration of above 250 micrograms of Pb (lead) per gram of dust (microgram/gram = ppm) to be elevated, found there were 101 out of 1,025 homes that were elevated (above 250 ppm). There were 27 homes above 975 ppm.

  The study also found that in homes with elevated dust lead, the lead was more digestible.

  "So not only is the lead higher in those homes in concentration, it's also more available for uptake in the body," she says.

  Rasmussen says large, epidemiological studies in Britain and the U.S. show house dust is a known pathway for lead to get into the body, especially for children through normal "hand to mouth" activities.

  "The U.S. has had a dust sampling protocol and set levels for many years because of the hazards of lead at very low levels," says Kathleen Cooper, senior researcher with the Canadian Environmental Law Association in arguing for stiff Canadian regulations. Canada has no guidelines for safe levels of lead in house dust, while provinces set individual guidelines for lead levels in soil.

  "This study provides the hard data that show we have just as much of a problem and an issue that needs to be addressed in Canada as has been addressed for a long time in the U.S. ... it's as if problems with lead stop at the border," Cooper said.

  Reference levels for blood lead have been 10 micrograms per decilitre, "but that is being revisited," she says.

  Medical researchers have long known that chronic lead exposure interferes with a variety of body processes and is toxic to many organs and tissues, including the heart, bones, intestines, kidneys, and reproductive and nervous systems. It interferes with the development of the nervous system and is therefore particularly toxic to children, causing potentially permanent learning and behaviour disorders. Symptoms include abdominal pain, confusion, headache, anemia, irritability, and in severe cases seizures, coma, and death.

  Earlier this month, the Advisory Committee on Childhood Lead Poisoning Prevention to the U.S. Centers for Disease Control and Prevention recommended a new standard for acceptable blood lead levels, and that the agency evaluate how to best replace the term blood lead "level of concern" in children and adults, according to Jay Dempsey, a health communication specialist with the CDC's National Centre for Environmental Health. CDC considers a blood lead level of 10 micrograms per decilitre to be of concern for children.

  The committee is recommending CDC adopt a reference level for lead at the level at which 97.5 per cent of the population have lower blood levels.

  Dempsey says this means that 2.5 per cent of the population have blood lead levels above the 97.5th percentile value. Under this recommendation, the term "elevated" will refer to the 97.5th percentile blood lead level because children in this range would have an "elevated" level compared to other children. "The recommendation is based on a growing body of scientific literature suggesting that adverse health effects may occur at blood lead levels lower than 10 micrograms per decilitre," he says. "The (committee's) report also emphasizes the need to prevent children from being exposed to lead before their blood lead levels can become elevated." CDC is currently reviewing the advisory committee's recommendations, and will decide whether or not to adopt them later this year.

  When Dr. Bruce Lanphear and his wife wanted to purchase a 1911 home in Vancouver several years ago, they knew it had undergone a "dramatic renovation" and wanted it tested for dust-lead levels.

  "We couldn't find anyone in Vancouver who does that," says the professor of Health Sciences at Simon Fraser University. He is also the principal investigator on a study examining fetal and early childhood exposures to environmental neurotoxins such as lead.

  "Absolutely, health-based standards or guidelines for lead in house dust in Canada are needed," he says.

  "We make a lot of noise about screening children for lead poisoning, and then once we identify a kid with lead poisoning we say, 'Oh, maybe they've been exposed to lead in their home' and then we go look at the home," he says. "What we've done by default is treat children as biological indicators of sub-standard housing or lead-hazardous housing. So the idea is to use a dust-lead screen or test to identify housing before a child is living in it."

  Lanphear believes further consideration should be given to screening homes built between 1940 and 1970, as well as when a home goes on the market.

  Rasmussen says the goal of this most recent study was to provide a nationally representative picture of lead in house dust, as opposed to individual cities.

  "We had done some preliminary house dust research here in Ottawa and in a couple of other locations and found surprising results that lead and cadmium and other metals of toxicological interest were elevated in house dust compared to garden soil. And when I say elevated, lead was approximately five times higher in house dust compared to garden soil from the same homes."

  In other words, investigators had been underestimating what was in the indoor environment.

  "It meant we have to go inside and take measurements and not just predict them."

  So investigators collected samples from 1,025 randomly selected homes in 13 cities (Richmond, Vancouver, Calgary, Regina, Burlington, Hamilton, Cambridge, Barrie, Thunder Bay, Sudbury, Gatineau, Montreal and Halifax) over four winters between 2007 and 2010. Residents were also asked whether the home had been renovated in the past year, and about hobbies and professions that might contribute to lead levels in the homes.

  She says people should be particularly aware of this during renovations.

  The Health Canada website says, "Effective house cleaning (e.g. using damp mopping) to remove dust and particles can reduce exposure to lead and other chemicals in house dust. Regular vacuuming of carpets and taking shoes off at the door is another way to prevent lead and other substances from getting into dust inside the home."

  "We're not trying to frighten people," Rasmussen says, "but they ought to be aware that those products can end up in their house dust if they don't clean up."

  Results of the study were released in 2011. Rasmussen says tolerable levels of lead in dust for children will now be the subject for future discussion and "whether setting reference levels is appropriate."

  But Kathleen Cooper says Health Canada has been discussing this issue "for a very long time. There already exists a mountain of information" about the low level effects of lead, "and not only on kids. It's also a cardiovascular risk."

  Meanwhile, Rasmussen says the universal message is to keep dust levels down, particularly around children.

  "The main issue is the hand to mouth, crawling around. Dust integrates everything. If it's falling from the paint, if the family has PVC blinds and the sun is baking those blinds, the sunlight breaks down the PVC and releases the lead, if they're bringing consumer products in and using them in hobbies, if the mom or dad are working in a munitions factory or some other occupation where they're bringing lead home in their clothes, tracking lead in from dirt, there's a multitude of different possible sources but they will end up in the dust."

  © Copyright (c) The Ottawa Citizen

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