Initial Steps to Prevent Lead Exposure and Poisoning (part 1)

Initial Steps to Prevent Lead Exposure and Poisoning from the Model National Lead Safety Policy Proposal created by The LEAD Group – i-iii

Initial Steps to Prevent Lead Exposure and Poisoning (Pt1) @ LeadSafeWorld

i) Establish a National Blood Lead Surveillance System, the data from which feeds government Lead Education and Awareness Campaigns

A National Blood Lead Surveillance System is a database into which pathology laboratories and/or health professionals/agencies are required to enter blood lead results and associated data. It is designed to aid government, health professionals and researchers to see trends and make decisions on lead safety policy and lead exposure and poisoning prevention research.

If a National Blood Lead Surveillance System is not already in place, the national government’s first responsibility in Primary and Secondary Lead Exposure Prevention, and Tertiary Lead Poisoning Prevention, is to set up such a Surveillance System to collect ALL blood lead testing results (not just those results which exceed the target blood lead limit at any one time). This surveillance will include active blood lead screening of individuals (and communities) identified through lead risk questionnaire screening, not just passive reporting of those cases identified by health care professionals.

Then to collate, analyse, and raise awareness of the conclusions of the analysis of the collected data.

Data collected for the National Blood Lead Surveillance System and entered by the pathology laboratory to include:

  • Name
  • Address
  • National health identifier (such as Medicare/NIH, patient number, NHS number)
  • Date and time of day of blood draw
  • Time of day
  • Date of birth
  • Gender
  • Ethnicity and/or race
  • Blood lead result
  • COVID-19 incidence (in the patient)

The doctor and/or local health agency is also required to enter data pertaining to interventions taken to reduce blood lead levels, and any information gleaned from particular case histories as to the sources of lead exposure in the individual/community, as stated below at v. As the National Blood Lead Surveillance System gains more data, an inventory of sources of lead exposure in the population (see Addendum 5, below) and a list of successful interventions will be generated.

Excellent examples of collation and analysis of blood lead data can be seen at the US Centers for Disease Control and Prevention (CDC 2019) website in the National Health and Nutrition Examination Survey (NHANES) (CDC 2021) Healthy Homes and Lead Poisoning Surveillance System (HHLPSS) and summary data is included in the National Report on Human Exposure to Environmental Chemicals (CDC 2022b). CDC have also written and published over 100 lead poisoning case histories and metanalyses in Morbidity and Mortality Weekly Report (MMWR)(CDC 2023) some examples are:

  • Elevated Blood Lead Levels Associated with Retained Bullet Fragments United States, 2003–2012 (Weiss et al 2017)
  • Lead in Spices, Herbal Remedies, and Ceremonial Powders Sampled from Home Investigations for Children with Elevated Blood Lead Levels — North Carolina, 2011–2018 (Angelon-Gaetz et al 2018)
  • Elevated Blood Lead Levels Among Employed Adults — United States, 1994–2013 (Alarcon 2016)

ii) Set national blood lead action levels for sub-populations and the environmental and consumer standards designed to lower blood lead levels, and to prevent and address environmental lead contamination

Blood lead testing is the gold standard for biomonitoring to assess recent exposure to lead. Repeated blood lead monitoring provides invaluable information as to lead exposure over time. Blood lead testing is also a useful tool in gauging the impact of actions intended to reduce the blood lead level as well as tracking the biokinetics of lead, that is, to assess how much lead from the bone (and other organ) stores has moved back into the bloodstream either due to treatment, extreme changes in activity levels (for example, becoming bedridden, or training for a marathon), hormonal changes such as during growth and pregnancy, or the demineralisation of the bones.

A blood lead action level is the level at which the government requires action to assist the blood lead level of the individual from a certain sub-population or leaded community to fall as quickly as possible below that level (see also 2.3, below).

Because research into the health effects of lead has demonstrated over many decades that the action level will always need to be lowered further on the basis of the findings of ongoing health effects research, it is vital to acknowledge that the blood lead action level/s set by any government will be chosen on political and economic grounds. On health grounds alone, there is no threshold of safety in lead exposure, but less lead means less damage.

It is irresponsible for a government to set the level/s very low in a country which has no hope of achieving it, especially if it still permits the addition of lead to paint, and the use of Ayurvedic medicines containing metal bhasmas, leaded AvGas for general aviation aircraft, the use of human sewage on food crops, etcetera – and even more irresponsible to set the level very high.

We have seen that what was considered to be an elevated blood lead level is NOT fixed. Initially, below 80 µg/dL was the “acceptable level” and this was progressively reduced (to 60, 50, 40, 25, 10, 5 and most recently 3.5 µg/dL) in the light of research revealing connections between blood lead levels and serious health risks. In 2009, WHO wrote, “The ideal exposure level for lead is less than 1 µg/dl”. Many of the world’s leading lead researchers have since recommended lead levels of no greater than 1 µg/dL of blood as the action level.

In Germany, the Wilhelm et al (2010) policy paper written on behalf of the Human Biomonitoring Commission of the German Federal Environment Agency set a global precedent in lead policy by replacing health-based blood lead levels of concern with individual action levels (called “reference values”) which differ for each sub-population, and were based on the 95th percentile blood lead result in a blood lead survey for that sub-population.

This meant that because 95% of German children (3–14 years of age) in the survey had a blood lead result below 3.5 μg/dL, the reference value became 3.5 μg/dL. Interventions were required from doctors and public health professionals for all child blood lead results 3.5 μg/dL and above.

The reference values for adults (Schulz et al 2007), which are based on data from the German Environmental Survey of 1998, are:

  • Men 9 μg/dL
  • Women 7 μg/dL

In 2012, the US CDC followed suit by choosing the 97.5 percentile reference value for children up to 72 months. Due to the NHANES ongoing national blood lead survey data, the 97.5 percentile reference value for children was further lowered to 3.5 μg/dL in 2021 (CDC 2022c).

As at early 2023, the widely used action level is a blood lead level no greater than 3.5 µg/dL, based on US NHANES blood lead national survey data from 2011-2014 which determined that 97.5% of young children in the US had a blood lead level below 3.5 µg/dL. The CDC policy is to reduce this “reference” [or action] blood lead level each four years, in line with the NHANES survey (repeated every two years) falling 97.5th percentile result (Caldwell et al 2017).

The combination of the US model of lowering the reference level periodically and the German model of having reference levels for sub-populations, provides the best existing model for other nations.

In 2012, as a result of a forum held by members of The LEAD Group’s Technical Advisory Board and others (including Professor Bruce Lanphear) (Taylor et al 2012), The LEAD Group set its action blood lead level to be 1 µg/dL.

The LEAD Group proposes that blood lead action levels be set and periodically lowered, and intervention actions determined by sub-population, including:

  • Birth cord blood lead levels
  • Children up to the age of 60 months
  • Children 5-12 years old
  • Children 13-20 years old
  • Adults 21-60 years old
  • Adults 61-70 years old
  • Adults 71-80 years old
  • Adults 81-90 years old
  • Adults 91-100 years old
  • Adults over 100 years old
  • Occupationally exposed sub-groups, for example, ship-breakers, gold assayists, metal and bone bhasma makers, plumbers, mine and smelters workers working with lead and lead-containing ores (zinc, copper, tin, silver or gold), fossil fuel burning facility workers, lead-acid battery manufacturing and recycling plant workers, vehicle recycling plant workers, painting contractors, remediators and restorers, shooters, leadlighters
  • Community members by age sub-population in highly leaded communities
  • Wildlife (aquatic and terrestrial)
  • Domestic animals
  • Farm animals (aquatic and terrestrial)

Occupational lead health and safety regulations will be updated to set more stringent blood lead action levels (for instance, removal from lead-risk work and return levels) by occupation. Enforcement of these up-to-date lead workers’ regulations is an essential component of Primary Lead Exposure Prevention. Policing of occupational lead health and safety regulations is vital and enforcement must include financial penalties for non-compliance.

Occupational lead health and safety regulations will be set based upon the percentile blood lead level determined by government for that particular occupation and regularly reduced through continuous surveying, implementation of the Hierarchy of Control for Managing Risk of Materials (the highest level of control is to eliminate lead from the process), and resultant reduction in blood lead levels.

When products or processes which cause occupational lead exposure have been identified, policy on producer responsibility will protect the environment from lead and further decrease lead exposure in industrial scale, backyard, black-market and hobby lead processes, such as in the collection and recycling of used lead-acid batteries (ULABs) (see xvii, below), spent leaded ammunition and the management of lead paint (see also 1.6, below).

iii) Set target blood lead levels and reduce them over time

A target blood lead level is the blood lead level to be achieved by everyone who has a blood lead test in the entire population or a sub-population by a certain date.

The decision to not include adults in public health policy on lead poisoning prevention was a common mistake of past programs based on inadequate information about health effects of lead exposure in adults.

It is important to acknowledge that, if, in current regulations, a certain group of people, such as workers, are permitted to exceed the national target blood lead level, that this was a political and economic decision (often based on industry-funded misinformation) made in the past (or at best, one made in ignorance), not a health-based decision.

Australian, New Zealand and United Kingdom governments need to consider political and economic factors in order to determine staged reductions of the target levels set out below:

  • All lead workers blood lead levels to be below 12 µg/dL by 2024,
  • All adults, children and cord blood lead levels to be below 10 µg/dL by 2025,
  • All children under 6 years of age and cord blood lead levels to be below 3.5 µg/dL by 2027,
  • All adults, children and cord blood lead levels to be below 5 µg/dL by 2028, and
  • All adults, children and cord blood lead levels to be below 1 µg/dL by 2031.

Each country’s government will have to decide on what is politically and economically viable, but stepped targets will enable the development of specific strategies so that lead safety can be achieved over a set timeframe.

Any province, state or other level of government (which for instance is dependent on the income of a large lead facility) within the country, can set its own target blood lead levels, as long as the economic and political factors for choosing the targets are acknowledged.

Define “success” in achieving a particular target as being no incidence of a blood lead level exceeding the target level by the target date, as revealed by follow-up national surveys and blood lead surveillance data. By setting both targets for blood lead levels and of zero incidence of cases above the sub-population’s blood lead target, a country has something by which to measure its progress in reducing the incidence of lead poisoning in its national or regional population or sub-population. The blood lead monitoring data is vital for re-evaluating the strategies needed to meet the targets (see 2.3, below).

Conduct follow-up national, lead-town and leaded community blood lead surveys to see if the blood lead target was met and to motivate and inform increased development or implementation of programs to achieve the next target. Just as with blood lead target of individuals, the formula is:

  • Survey
  • Respond
  • Re-survey
  • Respond afresh
  • Repeat until lead-safety is achieved
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