The health effects of lead levels below 100 µg/L
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News of 03/04/2013
In a scientific opinion entitled "Lead in food" published in April 2010, the European Food Safety Authority (EFSA) reported neurotoxic, developmental, cardiovascular and renal effects linked to blood lead levels(1) below 100 µg/L, a monitoring level commonly authorised internationally. This 100µg/L level is also used for detection monitoring and for mandatory declaration of cases of lead poisoning in France. In this context, ANSES was asked on 26 July 2011 by the Ministries of health and the environment to provide an opinion "regarding the health effects of blood lead levels below 100 µg/L".
The report by EFSA reported neurotoxic, developmental, cardiovascular and renal effects with blood lead levels which were previously considered low (levels below à 100 µg/L).
In response to the Ministries' request, an expert group was set up by ANSES. This working group analysed the epidemiological data describing the links between blood lead levels and various health effects. It based its conclusions on source studies, meta-analyses, published pooled data analyses and recent expertise reports from international (EFSA) and country-based (Health Canada, National Toxicology Program) organisations.
The opinion issued by the expert group concluded that the studies showing the effects of lead on blood pressure and on renal function in adults and showing deficiencies of the central nervous system in children, were a sufficiently robust scientific basis to conclude that harmful effects of lead levels below 100 µg/L did exist. These conclusions are in agreement with those expressed by the other national and international organisations which have recently assessed the effects of lead.
The results of this study show that the most sensitive effects linked to chronic exposure to lead are renal toxicity in adults and neurotoxicity in children. The expert group considered that the establishment of a blood lead level which uses renal effects in adults as the critical effect would protect the entire population, including children, against all the harmful effects of lead identified up to now.
The study by Navas-Acien et al. (2009) based on the 1999–2006 NHANES study (USA) was selected as the key study for establishing the renal toxicity of lead and for setting critical blood lead levels(2). Based on this, a critical blood lead level of 15 µg/L is associated with a rise in prevalence of chronic kidney disease(3).
In addition, observation studies have shown over the last few decades a reduction in lead levels in the public drinking water supply and in foodstuffs, due to the implementation of public policy measures for managing the health risks of lead.
As a result of this expert assessment, the Agency recommends:
- reviewing, in the light of the newly available data, all of the reference values based on blood lead levels, including those applicable to the work environment,
- pursuing efforts aiming to limit the population's exposure to lead,
- pursuing biomonitoring studies, in order to monitor blood lead levels in the entire population.
(1) Blood lead level: measurement of the amount of lead per litre of blood
(2) Concentration of lead in the blood in conjunction with a critical health effect, namely an effect on the kidneys.
(3) Defined as persistence over a period of more than three months of a glomerular filtration rate below 60 mL/min/1.73 m2 body surface.