LEAD Action News
LEAD Action News vol 8 no 2, 2001, 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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PDF version of this file: New strategies needed to cut lead pollution

Fully Referenced Expanded Version of
"New strategies needed to cut lead pollution",
Guest Article, Science and Technology Column, Canberra Times,

Thursday 25th January 2001

Lead - From The Petrol Bowser To Blood And Bone part 1

by Elizabeth O'Brien, National Coordinator of The LEAD Group and
Mariann Lloyd-Smith, Coordinator of the National Toxics Network

ct.jpg (63756 bytes)

A RESPONSE TO: "Lead may be dead but we've been had"

PDF version of this file: New strategies needed to cut lead pollution

Lead - from the air - into our blood

The particles of airborne lead from traffic are extremely small and are inhaled deep into the lungs (Cribb, 1994). An abundance of studies has shown that lead in all forms (including from vehicle exhausts) is both inhaled into the lungs and absorbed. Though it’s a long quote, it's worth reading the following from NRC (1993, p144-6):

"Humans absorb lead predominantly through the gastrointestinal and respiratory tracts…

"Inhaled lead is deposited in the upper and lower reaches of the respiratory tract. Deposition in the upper portion leads to ciliary clearance of the lead, swallowing, and absorption from the intestine. Smaller lead particles, especially those less than 1 um in statistically averaged diameter, penetrate the lower, pulmonary portion of the respiratory tract and undergo absorption from it.

"Human studies (Chamberlain, 1983; EPA, 1986a) have shown that about 30-50% of inhaled lead is retained by the lungs (the range reflects mainly particle size and individual breathing rate). These studies have used unlabelled lead aerosol (Kehoe, 1961a,b,c), radio labelled oxide aerosol (Chamberlain et al, 1978), lead fumes inhaled by volunteers (Nozaki, 1966), ambient air lead around motorways and encountered by the general population (Chamberlain et al, 1978; Chamberlain, 1983), lead salt aerosols inhaled by volunteers (Morrow et al, 1980), and lead in forms encountered in lead operations, fumes, dusts, etc. (Mehani, 1966). Most (over 95%) of whatever lead is deposited in the human pulmonary compartment is absorbed (Rabinowitz et al, 1977; Chamberlain et al, 1978; Morrow et al, 1980). Thus, the overall rate of uptake is governed by lung retention (ie, 30-50%). Uptake occurs rapidly, generally in a matter of hours.

"Evidence of complete and rapid uptake can be gleaned from analysis of autopsy lung tissue (Barry, 1975; Gross et al, 1975). The chemical form of inhaled lead appears to have little effect on uptake rate (Chamberlain et al, 1978; Morrow et al, 1980)."

Having been one of the instigators (O'Brien, 1992; Gordon 1992; Greenpeace 1992) and also a community representative at Ros Kelly's Lead Roundtable, one of the present writers, Elizabeth O'Brien, can vouch for the fact that the 1992 Sydney blood lead study was brought to the attention of Ros Kelly. But no blood lead studies were actually considered at the Roundtable (CEPA, 1993a). Instead, the conclusions of the review of 600 lead studies, by the International Program on Chemical Safety (IPCS) of the World Health Organisation (WHO, 1992) and the directive of the National Health and Medical Research Council (NHMRC, 1993) were accepted as the starting point. As Ros Kelly (1993) said in her opening speech, "The purpose of our meeting today is to talk about how we, as a nation, can reduce the amount of lead in petrol and increase the use of unleaded petrol. In this way, we can begin to solve the very serious problem we have of a large number of children in Australia being adversely affected by lead." The graph showing the lock step reduction of US blood lead and petrol lead levels (Annest, 1983 - see Figure 19.1 pp 1500 at http://www.who.int/publications/cra/chapters/volume2/1495-1542.pdf) was not actually considered at the Roundtable meeting at all, though it was one of the 600 studies reviewed by WHO.

The price differential was regarded as a fair and equitable move for the government to make because it had been shown in a number of OECD countries that a price differential led to a more rapid phase-out of leaded petrol. The OECD had stated in 1992 that: "because the phasing out of leaded gasoline has led to dramatic decreases in atmospheric lead levels, it is clearly the most important single measure for lead risk reduction. Ros Kelly herself noted (as did the CEPA Options Paper, 1993) that though people who owned older cars would be the hardest hit by the price differential, as the lowest socio-economic groups are also the most likely to be lead poisoned, the poorest people in the community would have the most to gain from the new levy, in terms of reduced lead pollution.

The mixture of stakeholders at the Roundtable all understood the logic that if you add lead to petrol, it will raise air lead levels, everyone breathes, so blood lead levels will be raised throughout the community - we can call this the baseline blood lead level. Then if you add on to that lead from any other of a range of sources, some people in the population will have a high blood lead level. So public health policies are currently ensuring throughout the world that the baseline (the lead contributed to blood by lead from petrol) is as low as possible - because eliminating lead from petrol is one of the cheapest and most cost effective ways of reducing the number of people with high blood lead levels. That's why, to our shame, 55 countries will have eliminated lead from petrol before Australia does, that is, by 1st January 2002 (LEAD Group, 2000).

PDF version of this file: New strategies needed to cut lead pollution

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