I don’t mean bullets. The crime waves that afflicted many parts of the
world and then, against all predictions, collapsed, were ascribed, in an
article published by
Mother Jones last week, to the rise and fall in the use of lead-based paint and leaded petrol (1).
It’s ridiculous – until you see the evidence. Studies between cities,
states and nations show that the rise and fall in crime follows, with a
roughly 20-year lag, the rise and fall in the exposure of infants to
trace quantities of lead (2,3,4). But all that gives us is correlation:
an association that could be coincidental. The
Mother Jones article, based on several scientific papers, claimed causation.
I began by reading the papers. Do they say what the article claims? They
do. Then I looked up the citations: the discussion of those papers in
the scientific literature. The three whose citations I checked have been
mentioned, between them, 301 times (5). I went through all these
papers (except the handful in foreign languages), as well as dozens of
others. To my astonishment, I could find just one study attacking the
thesis (6), and this was sponsored by the Ethyl Corporation, which
happens to have been a major manufacturer of the petrol additive
tetraethyl lead. I found many more supporting it. Crazy as this seems,
it really does look as if lead poisoning could be the major cause of the
rise and fall of violent crime.
The curve is much the same in all the countries these papers have
studied. Lead was withdrawn first from paint and then from petrol at
different times in different places (beginning in the 1970s in the US in
the case of petrol and the 1990s in many parts of Europe), yet, despite
these different times and different circumstances, the pattern is the
same: violent crime peaks around 20 years after lead pollution peaks
(7,8,9). The crime rates in big and small cities in the US, once wildly
different, have now converged, also some 20 years after the phase-out
(10).
Nothing else seems to explain these trends. The researchers have
taken great pains to correct for the obvious complicating variables:
social, economic and legal factors. One paper found, after 15 variables
had been taken into account, a four-fold increase in homicides in US
counties with the highest lead pollution (11). Another discovered that
lead levels appeared to explain 90% of the difference in rates of
aggravated assault between US cities (12).
A study in Cincinnati finds that young people prosecuted for
delinquency are four times more likely than the general population to
have high levels of lead in their bones (13). A meta-analysis (a study
of studies) of 19 papers found no evidence that other factors could
explain the correlation between exposure to lead and conduct problems
among young people (
14).
Is it really so surprising that a highly potent nerve toxin causes
behavioural change? The devastating and permanent impacts of even very
low levels of lead on IQ have been known for many decades. Behavioural
effects were first documented in 1943: infants who had tragically
chewed the leaded paint off the railings of their cots were found,
years after they had recovered from acute poisoning, to be highly
disposed to aggression and violence (15).
Lead poisoning in infancy, even at very low levels, impairs the
development of those parts of the brain (the anterior cingulate cortex
and prefrontal cortex) which regulate behaviour and mood (16). The
effect is stronger in boys than in girls. Lead poisoning is associated
with attention deficit disorder (17,18), impulsiveness, aggression and,
according to one paper, psychopathy (19). Lead is so toxic that it is
unsafe at any level (21, 22).
Because they were more likely to live in inner cities, in unrenovated
housing whose lead paint was peeling and beside busy roads, African
Americans have been subjected to higher average levels of lead
poisoning than white Americans. One study, published in 1986, found
that 18% of white children but 52% of black children in the US had over
20 milligrammes per decilitre of lead in their blood (23); another
that, between 1976 and 1980, black infants were eight times more likely
to be carrying the horrendous load of 40mg/dl (24).
This, two papers
propose, could explain much of the difference in crime rates between
black and white Americans (25), and the supposed difference in IQ
trumpeted by the book The Bell Curve (26).
There is only one remaining manufacturer of tetraethyl lead on earth.
It’s based in Ellesmere Port in Britain, and it’s called Innospec. The
product has long been banned from general sale in the UK, but the
company admits on its website that it’s still selling this poison to
other countries ( 27).
Innospec refuses to talk to me, but other reports claim that
tetraethyl lead is being exported to Afghanistan, Algeria, Burma, Iraq,
North Korea, Sierra Leone and Yemen (28,29), countries afflicted either by chaos or by governments who don’t give a damn about their people.
In 2010 the company admitted that, under the name Associated Octel,
it had paid millions of dollars in bribes to officials in Iraq and
Indonesia to be allowed to continue, at immense profit, selling
tetratethyl lead (30).
Through an agreement with the British and US courts, Innospec was let
off so lightly that Lord Justice Thomas complained that “no such
arrangement should be made again.” (31) God knows how many lives this firm has ruined.
The UK government tells me that because tetraethyl lead is not on the
European list of controlled exports, there is nothing to prevent
Innospec from selling to whoever it wants (32). There’s a term for
this: environmental racism.
If it is true that lead pollution, whose wider impacts have been
recognised for decades, has driven the rise and fall of violence, then
there lies, behind the crimes that have destroyed so many lives and
filled so many prisons, a much greater crime.
First published in the
Guardian. Courtesy: www.monbiot.com
References:
1.
http://www.motherjones.com/environment/2013/01/lead-crime-link-gasoline
2. Rick Nevin, May 2000. How Lead Exposure Relates to Temporal
Changes in IQ, Violent Crime, and Unwed Pregnancy. Environmental
Research, Vol.83, Issue 1, pp1–22.
http://dx.doi.org/10.1006/enrs.1999.4045
3. Rick Nevin, 2007. Understanding international crime trends: the
legacy of preschool lead exposure. Environmental Research Vol. 104,
pp315–336.
doi:10.1016/j.envres.2007.02.008
4. Jessica Wolpaw Reyes, May 2007. Environmental Policy as Social
Policy? The Impact of Childhood Lead Exposure on Crime. National Bureau
of Economic Research Working Paper 13097.
http://www.nber.org/papers/w13097
5. The three papers whose citations I checked were Rick Nevin, May 2000, as above;
Rick Nevin, 2007, as above and Jessica Wolpaw Reyes, May 2007, as above.
6. Patricia L. McCalla and Kenneth C. Land, 2004. Trends in
environmental lead exposure and troubled youth, 1960–1995: an
age-period-cohort-characteristic analysis. Social Science Research
Vol.33, pp339–359.
7. PB Stretesky and MJ Lynch, May 2001. The relationship between lead
exposure and homicide. Archives of Pediatrics and Adolescent Medicine,
vol.155, no.5, pp579-82.
8. Paul B. Stretesky and Michael J. Lynch, June 2004. The
Relationship between Lead and Crime.Journal of Health and Social
Behavior, Vol.45, no.2, pp214-229. doi: 10.1177/002214650404500207
9. Howard W. Mielke and Sammy Zahran, 2012. The urban rise and fall
of air lead (Pb) and the latent surge and retreat of societal violence.
Environment International Vol. 43, pp 48–55.
doi:10.1016/j.envint.2012.03.005
10. Bureau of Justice, no date given. Homicide Trends in the U.S.
http://bjs.ojp.usdoj.gov/content/homicide/city.cfm
11. PB Stretesky and MJ Lynch, May 2001, as above.
12. Howard W. Mielke and Sammy Zahran, 2012, as above.
13. Herbert L. Needleman et al, 2002. Bone lead levels in adjudicated
delinquents: a case control study. Neurotoxicology and Teratology,
Vol. 24, pp711 –717.
14. David K. Marcus, Jessica J. Fulton and Erin J. Clarke, 2010. Lead
and Conduct Problems: a Meta-Analysis. Journal of Clinical Child and
Adolescent Psychology, vol.39, no.2, pp234-241.
http://dx.doi.org/10.1080/15374411003591455
15. R.K. Byers and E.E. Lord, 1943. Late effects of lead poisoning on
mental development, American Journal of Diseases of Children, Vol. 66,
pp. 471– 483.
16. Kim M Cecil et al, 2008. Decreased Brain Volume in Adults with
Childhood Lead Exposure. Decreased Brain Volume in Adults with
Childhood Lead Exposure. PLoS Medicine, vol. 5, no. 5.
doi:10.1371/journal.pmed.0050112
17. Joel T. Nigg et al, January 2010. Confirmation and Extension of
Association of Blood Lead with Attention-Deficit/Hyperactivity Disorder
(ADHD) and ADHD
Symptom Domains at Population-Typical Exposure Levels. J Child Psychol
Psychiatry. Vol. 51, no.1, pp.58–65.
doi:10.1111/j.1469-7610.2009.02135.x.
18. Joe M. Braun et al, 2006. Exposures to Environmental Toxicants
and Attention Deficit Hyperactivity Disorder in U.S. Children.
Environmental Health Perspectives vol. 114, pp.1904–1909.
doi:10.1289/ehp.9478
19. John Paul Wright, Danielle Boisvert and Jamie Vaske. July 2009.
Blood Lead Levels in Early Childhood Predict Adulthood Psychopathy.
Youth Violence and Juvenile Justice, vol.7, no.3, pp.208-222. doi:
10.1177/1541204009333827
20. Rick Nevin, 2007, as above, reports that “there is no lower blood lead threshold for IQ losses”.
21. David Bellinger concludes that “No level of lead exposure appears
to be ‘safe’ and even the current ‘low’ levels of exposure in children
are associated with neurodevelopmental deficits.”. April 2008. Very
low lead exposures and children’s neurodevelopment. Current Opinion in
Pediatrics, Vol.20, no.2, pp172-177. doi: 10.1097/MOP.0b013e3282f4f97b
23. Royal Society of Canada, 1986. Lead in the Canadian Environment.
Science and Regulation. Cited by Rick Nevin, 2007, as above.
24. Agency for Toxic Substances and Disease Registry, 1988. The
Nature and Extent of Lead Poisoning in Children in the United States.
US Department of Health and Human Services. Cited by Rick Nevin, 2007,
as above.
25. Rick Nevin, 2007, as above.
26. Rick Nevin, February 2012. Lead Poisoning and The Bell Curve. Munich Personal RePEc Archive MPRA Paper No. 36569.
http://mpra.ub.uni-muenchen.de/36569/
27.
http://www.innospecinc.com/octane-additives.html
28.
http://www.economist.com/news/21566385-lead-tantalisingly-close-death-2013-world-meant-stop-using-leaded-petrol-toxin
29. Anne Roberts and Elizabeth O’Brien, 2011. Supply Chain for the Lead in Leaded Petrol. LEAD Action News, vol.11, no.4.
30.
http://www.guardian.co.uk/uk/2010/mar/18/firm-bribes-banned-chemical-tetraethyl
31.
http://www.guardian.co.uk/business/2010/jun/30/octel-petrol-iraq-lead
32. I was passed by Defra to the Department for Transport, then by
the DfT to the Department for Business, which told me it was all down
to the European list. It was clear that none of them were remotely
interested in the issue, or had considered it before.
