LEAD Action News
LEAD Action News Volume 12 Number 3, May 2012, ISSN 1324-6011
Incorporating Lead Aware Times ( ISSN 1440-4966) and Lead Advisory Service News (ISSN 1440-0561)
The Journal of The LEAD (Lead Education and Abatement Design) Group Inc.

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World's Best Practice Lead Assessment Advice for Australian Parents, and Health and Child-Care Professionals –

based on extracts from the Centers for Disease Control's (CDC's)
January 2012 recommendations on lead, with permission

Extracts chosen by, and Australian info added by Elizabeth O’Brien, Manager,
 Global Lead Advice & Support Service (GLASS) run by The LEAD Group Inc. 14th February 2012.

According to the “Low Level Lead Exposure Harms Children: A Renewed Call for Primary Prevention - Report of the Advisory Committee on Childhood Lead Poisoning Prevention of the Centers for Disease Control and Prevention” {Preliminary Draft 29th December 2011 which was approved on 4th January 2012} AT http://www.cdc.gov/nceh/lead/ACCLPP/Final_Document_010412.pdf :

The goal of primary prevention is that all homes will become lead-safe and not contribute to childhood lead exposure. Given the involuntary nature of lead exposures associated with housing and other sources, and the risks associated with lead exposure, all exposures should be kept as low as possible. Controlling potential lead exposures in a child’s environment before they cause damage will be the only way to prevent childhood lead poisoning. Special vigilance is also needed around renovation and remodeling activities in older homes, when lead dust levels are known to spike.

Lead-contaminated dust, soil, paint, and water are all associated with blood lead levels above the reference value in children [in children 1-5 years old, that is, currently 10 μg/dL (10 micrograms per decilitre) in the USA and proposed, in January 2012, to be 5 μg/dL], as are other risk factors, such as parent’s occupation, age of housing, poverty and ethnicity. Although most published research associating environmental lead exposures and BLLs [blood lead levels] for children was done with children who had significantly higher levels than is common today, there are notable exceptions, such as the recent NHANES [US National Health and Nutrition Examination Survey] analyses of dust and children’s BLLs [75, 76].

Multiple risk factors/ exposures contribute to BLLs less than 10 μg/dL. In fact investigations conducted in response to a child with a BLL greater than 15 μg/dL often fail to identify a single source or risk factor and the challenge is even greater for lower level exposures. The inability to identify a single source of exposure in these cases underlines the fact that lead remains a multi-media pollutant requiring integrated exposure assessment and reduction. However in the U.S., lead-based paint hazards, including deteriorated paint, and lead-contaminated dust and soil still remain by far the largest contributors to childhood lead exposure on a population basis [56].

Although the U.S. Environmental Protection Agency has established recommended lead exposure limits for dust, soil, and water in homes, these levels are not health based and were not selected to be protective of exposures below 10 μg/dL. For example, the current hazard standard for dust lead levels for floors of 40 μg/ft2 [(micrograms per square foot), approx. 400 μg/m2 (micrograms per square metre)] is associated with potential exposures among children above the [1991 US, 1993 Australian] reference value [of 10 μg/dL lead in blood].

Significant research on children with BLLs greater than 25 μg/dL has focused on the efficacy of a range of lead hazard controls and abatement of lead hazards (including dust, soil, and paint) and in uncontrolled trials has shown statistically significant declines in BLLs in the range of 20-30 percent at follow up (reference [70] p. 95). Only very limited research has examined the efficacy of lead abatement techniques and interim controls for children with BLLs as low as 5-9 μg/dL [77]. Evaluation of the decline in BLLs following environmental interventions is problematic because bone lead stores may remain a significant contributor to BLLs for many years following removal from further exposure and/or chelation. 

As we pursue and prioritize a primary prevention model, we move beyond the goal of interventions just aimed at lowering a child’s BLL. The new emphasis must be on efforts that are successful at reducing exposures to known sources. Prevention requires that we reduce environmental exposures from soil, dust, paint and water before it contributes to a child’s exposure. Because blood lead integrates all sources of exposure including lead released from bone stores, it should not be used as a sole measure to determine whether or not a specific environmental exposure has been successfully addressed. Instead, environmental measurements, e.g., soil, or dust testing, are a more direct and preferred means of assessing whether an intervention has succeeded.

Environmental testing is a useful means to focus limited hazard control resources…

Environmental investigations in housing built before 1978 [in 1978, residential paint lead was limited to 0.06% in the USA. The “best equivalent” year when residential paint lead was limited to 0.10% (nearly twice the US level) in Australia, was 1997. Residential paint lead in Australia as at January 2012 is still limited to 0.10%] should include:

  • - History of child’s exposure and questionnaire on potential sources of exposure
  • - Visual inspection of the home or facility where the child spends considerable time to identify peeling paint, moisture damage, and other relevant housing conditions;
  • - Measurements of lead levels in dust (with single surfaces wipe samples), soil, water, and paint that is not intact or otherwise separating from the substrate should be conducted…

In addition, environmental assessments may include investigation of potential exposures from other sources including, but not limited to, toys and other products, pottery [ceramic tableware or ovenware], cosmetics, folk remedies, food and candy with significant lead content. The potential for take-home exposures must also be evaluated based on the parent’s occupation and hobbies…

Environmental assessments in response to children with elevated BLLs are also appropriate in homes built after 1978 [Australian best equivalent year 1997] when the use of lead paint was restricted.

Recent analysis of NHANES blood and dust lead data, for example, indicates that when floor dust lead is less than 112 μg/ft2 [approx. 120 μg/m2], the geometric mean BLL is 3.9 μg/dL [75, 76]. Water and dust lead levels are currently under review by EPA. (See http://yosemite.epa.gov/sab/sabproduct.nsf/RSSRecentHappeningsBOARD/9c733206a5d
6425785257695004f0cb1!OpenDocument&TableRow=2.2
and http://water.epa.gov/lawsregs/rulesregs/sdwa/lcr/index.cfm#LongTermRevisions

A successful primary prevention strategy must start with an environmental assessment in order to set priorities and inform the selection of appropriate response actions. Environmental inspections and testing are also necessary responses to cases where a child has already been exposed …

Selected References from the CDC recommendations:

70. Centers for Disease Control and Prevention. Managing Elevated Blood Lead Levels Among Young Children. Recommendations from the Advisory Committee on Childhood Lead Poisoning Prevention. CDC, Atlanta: 2002. http://www.cdc.gov/nceh/lead/CaseManagement/caseManage_main.htm

75. Dixon SL et al., Exposure of U.S. children to residential dust lead, 1999-2004: II. The contribution of lead-contaminated dust to children's blood lead levels. Environmental Health Perspectives, 38 2009. 117:468-74. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2661919/pdf/ehp-117-468.pdf

76. Gaitens JM et al., Exposure of U.S. children to residential dust lead, 1999-2004: I. Housing and demographic factors. Environmental Health Perspectives, 2009. 117:461-7. http://www.ehponline.org/members/2008/11917/11917.pdf

77. Clark S et al., Effects of HUD-supported lead hazard control interventions in housing on children's blood lead. Environmental Research, 2011. 111:301-11. http://www.sciencedirect.com/science/article/pii/S0013935110001842

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