IL SONNO DELLA RAGIONE GENERA MOSTRI

 
[...] Il 24 Novembre 2005 si tenne presso il Comune di Forlì una Audizione Pubblica circa i rischi connessi all'incenerimento di rifiuti, alla presenza del prof. Lorenzo Tomatis e del prof. Gianni Tamino. In quell'occasione il Prof. Tomatis esordì dicendo: La futura generazione non ci perdonerà i danni che noi le stiamo arrecando, identificando proprio nei bambini la popolazione più fragile e più a rischio per gli agenti chimici inquinanti.

A questo proposito e sulla scia di una letteratura scientifica imponente, che ha ormai ampiamente dimostrato come il cervello infantile e il sistema nervoso in via di sviluppo rappresentino veri e propri tessuti-bersaglio per centinaia di molecole tossiche, assume grande rilievo l'allarme lanciato lo scorso 7 novembre dalla prestigiosa rivista LANCET che - preannunciando l’imminente pubblicazione di un importante studio condotto dai ricercatori della Harvard School of Public Health minaccia di un dramma socio-sanitario “globale”, che si diffonde in modo subdolo e incontrollabile, perché gli effetti di un’esposizione cronica e collettiva sfuggono alle abituali modalità di indagine e di ricerca… e per notificare le prime, probabili cifre di una tragedia lungamente annunciata, eppure evitabile, secondo cui, nel mondo: Un bambino su sei presenterebbe danni documentabili al sistema nervoso e problemi funzionali e comportamentali che vanno dal deficit intellettivo, alla sindrome da iperattività, all'autismo (con costi enormi - sia detto per inciso - anche sul piano economico: visto che nei soli Stati Uniti d'America i costi per i danni neurologici da piombo nei bambini ammonterebbero a circa 43 miliardi di dollari e per quelli da mercurio a 8.7 miliardi).

E' una ben amara soddisfazione vedere che oggi alcune Università e Riviste scientifiche tra le più prestigiose al mondo denunciano in modo chiaro e perentorio ciò che per anni, noi Medici per l'Ambiente, ci siamo sforzati di documentare, affermando con forza che troppo spesso la medicina occidentale ha privilegiato obiettivi e strategie di lotta contro malattie e sofferenze che sono il prodotto (assolutamente evitabile) di modelli di vita stressanti, consumistici, inquinanti… e che troppo spesso i nostri esperti - politici, economisti ed ecologisti  hanno parlato di sostenibilità, prevenzione, promozione della salute, per poi varare o legittimare normative e leggi - uniche al mondo - che non tengono in nessun conto la tutela dell’ambiente e la salute dei cittadini. Come quelle con cui si equiparano i rifiuti urbani a fonti rinnovabili di energia; si permette a chi incenerisce di accedere a cospicui finanziamenti pubblici (CIP 6, Certificati Verdi,  proprio in questi giorni rinnovati!) che andrebbero riservati alle vere rinnovabili; si consente che materiali tossici e nocivi (Legge Delega n. 152  03/04/2006) godano di tali finanziamenti… per fare in modo che il loro smaltimento, che prima rappresentava un costo per le Aziende, si trasformi in ulteriore fonte di profitto, ma ad un prezzo inaccettabile per la Salute collettiva e insostenibile per le generazioni future.

Abbiamo imparato che non si può sperare di risolvere alcun problema - per quanto drammatico e tragico - se prima non lo si riconosce: abbiamo fatto un primo, importante passo, riconoscendo di essere giunti ad un punto cruciale per la Vita stessa sul nostro pianeta. A questo punto nessuno ha il diritto di definirci allarmisti: non possiamo più tacere mentre la stessa atmosfera del pianeta ha la febbre, gli squilibri climatici alterano gli ecosistemi e persino il mondo dei microbi e dei virus è in subbuglio...

Basta con le indecisioni e i tentennamenti: non possiamo rischiare di  essere complici, anche solo col nostro "torpore", di quella che potrebbe rivelarsi una catastrofe biologica di grandi dimensioni. Biologi, genetisti, (bio)chimici, microbiologi, oncologi, epidemiologi, immunologi, pediatri: è veramente venuto il momento per tutti i medici e gli uomini di scienza di assumersi le proprie responsabilità... anche per non rischiare di essere accusati, in futuro, di non aver fatto abbastanza per difendere la Salute pubblica e gli equilibri stessi della biosfera, minacciati da una deriva ipertecnologica che stravolge la scienza in nome del profitto.

Questo appello si rivolge a tutti gli adulti, che hanno fatto - almeno fino ad ora - assai poco per riconoscere le proprie responsabilità e per contrastare la pericolosa deriva di una civiltà e di una scienza che potrebbero garantire benessere e sicurezza a tutti e che rischiano invece di minare la nostra esistenza.

Sottoscrivete questa lettera, diffondete queste conoscenze. Soltanto in questo modo possiamo sperare di responsabilizzare coloro che si sono assunti l'onore e l'onere di prendere le decisioni più importanti, in rappresentanza e a garanzia della collettività e che troppo spesso si rivelano inadeguati al compito che si sono assunti e più in generale tutti coloro che gestendo potere, ricchezza, informazione svolgono un ruolo cruciale in questo sistema… perché ricordino che le loro scelte influiranno sulla vita dei loro figli, che hanno il diritto di vivere in un mondo in cui siano garantiti quantomeno i diritti primari: accesso all'acqua (pubblica e pulita); cibo sano; aria respirabile e... cervelli in grado di funzionare.

Lavoriamo insieme: medici, genitori, studenti.. per promuovere una cultura della responsabilità; per chiedere alle autorità locali di tutelare il territorio e la salute dei cittadini, e al nostro Governo di abolire leggi vergognose che ci pongono fuori dalla stessa Comunità Europea.

Riscopriamo insieme il valore della partecipazione e della democrazia,  dimostriamo nei fatti che vogliamo proteggere i nostri bambini, le città in cui viviamo, l'aria che respiriamo, scrolliamoci di dosso questo fatalismo, questo sentimento tragico di ineluttabilità delle cose, ricordando anche quanto il Prof. Tomatis un anno fa ci disse: A Forlì ho visto la fiammella del cambiamento ed anche un grande incendio nasce da una scintilla.

Non è troppo tardi: dobbiamo credere che ci siano molte persone con un pizzico di sana follia, perché - come diceva Albert Einstein - Solo coloro che sono così folli da pensare di cambiare il mondo, ci riescono
 
Ferdinando Borroni  (Medicina Generale), Giuseppe Roberto Burgio (Pediatra); Ernesto Burgio (Pediatra), Andrea Galassi ( Medicina Generale), Gabriella Filippazzo (Epidemiologo); Valerio Gennaro (Epidemiologo), Patrizia Gentilini (Oncoematologo); Marina Melandri (Medicina Generale); Ruggero Ridolfi (Oncologo), Gianni Tamino (Biologo); Giuseppe Timoncini (Pediatra), Lorenzo Tomatis (Patologo Medico) ...


A Silent Pandemic: Industrial Chemicals Are Impairing the Brain Development of Children Worldwide


Tuesday, November 7, 2006

Boston, MA – Fetal and early childhood exposures to industrial chemicals in the environment can damage the developing brain and can lead to neurodevelopmental disorders (NDDs) - autism, attention deficit disorder (ADHD), and mental retardation. Still, there has been insufficient research done to identify the individual chemicals that can cause injury to the developing brains of children.

In a new review study, published online in The Lancet on November 8, 2006, and in an upcoming print issue of The Lancet, researchers from the Harvard School of Public Health and the Mount Sinai School of Medicine systematically examined publicly available data on chemical toxicity in order to identify the industrial chemicals that are the most likely to damage the developing brain.

The researchers found that 202 industrial chemicals have the capacity to damage the human brain, and they conclude that chemical pollution may have harmed the brains of millions of children worldwide. The authors conclude further that the toxic effects of industrial chemicals on children have generally been overlooked.

To protect children against industrial chemicals that can injure the developing brain, the researchers urge a precautionary approach for chemical testing and control. Such an approach is beginning to be applied in the European Union. It puts in place strong regulations, which could later be relaxed, if the hazard were less than anticipated, instead of current regulations that require a high level of proof. At present in the U.S., requirements for toxicity testing of chemicals are minimal.

The human brain is a precious and vulnerable organ. And because optimal brain function depends on the integrity of the organ, even limited damage may have serious consequences, says Philippe Grandjean, adjunct professor at Harvard School of Public Health and the study’s lead author.
 
One out of every six children has a developmental disability, usually involving the nervous system. Treating NDDs is difficult and costly to both families and society. In recent decades, a gathering amount of evidence has linked industrial chemicals to NDDs. Lead, for example, was the first chemical identified as having toxic effects to early brain development, though its neurotoxicity to adults had been known for centuries.

A developing brain is much more susceptible to the toxic effects of chemicals than an adult brain. During development, the brain undergoes a highly complex series of processes at different stages. An interference - for example, from toxic substances - that disrupts those processes, can have permanent consequences. That vulnerability lasts from fetal development through infancy and childhood to adolescence. Research has shown that environmental toxicants, such as lead or mercury, at low levels of exposure can have subclinical effects - not clinically visible, but still important adverse effects, such as decreases in intelligence or changes in behavior.

Grandjean and co-author Philip J. Landrigan, Professor at Mount Sinai School of Medicine, compiled a list of 202 environmental chemicals known to be toxic to the human brain using the Hazardous Substances Data Bank of the National Library of Medicine and other data sources. (The authors note that the list should not be regarded as comprehensive; for example, the number of chemicals that can cause neurotoxicity in laboratory animal tests exceeds 1,000.)

The authors then examined the published literature on the only five substances on the list - lead, methylmercury, arsenic, PCBs and toluene - that had sufficient documentation of toxicity to the developing human brain in order to analyze how that toxicity had been first recognized and how it led to control of exposure. They found a similar pattern in how the risks of each substance were documented: first, a recognition of adult toxicity and episodes of poisoning among children, followed by a growing body of epidemiological evidence that exposure to lower levels of the substances caused neurobehavioral deficits in children.

Even if substantial documentation on their toxicity is available, most chemicals are not regulated to protect the developing brain, says Grandjean. Only a few substances, such as lead and mercury, are controlled with the purpose of protecting children. The 200 other chemicals that are known to be toxic to the human brain are not regulated to prevent adverse effects on the fetus or a small child.

Grandjean and Landrigan conclude that industrial chemicals are responsible for what they call a silent pandemic that has caused impaired brain development in millions of children worldwide. It is silent because the subclinical effects of individual toxic chemicals are not apparent in available health statistics. To point out the subclinical risk to large populations, the authors note that virtually all children born in industrialized countries between 1960 and 1980 were exposed to lead from petrol, which may have reduced IQ scores above 130 (considered superior intelligence) by more than half and increased the number of scores less than 70. Today, it’s estimated that the economic costs of lead poisoning in U.S. children are $43 billion annually; for methylmercury toxicity, $8.7 billion each year.

“ìOther harmful consequences from lead exposure include shortened attention spans, slowed motor coordination and heightened aggressiveness, which can lead to problems in school and diminished economic productivity as an adult. And the consequences of childhood neurotoxicant exposure later in life may include increased risk of Parkinson’s disease and other neurogenerative diseases,”ì says Landrigan.

The researchers believe that the total impact of the pandemic is much greater than currently recognized. In supplementary documentation (see below for a link), about half of the 202 chemicals known to be toxic to the brain are among the chemicals most commonly used.  

Testing chemicals for toxicity is a highly efficient public health measure. However, less than half of the thousands of chemicals currently used in commerce have been tested to assess acute toxicity and, although new chemicals undergo more thorough testing, access to the data may be restricted because companies fear exposing proprietary information. Also, current toxicity testing rarely includes neurobehavioral functions.

The brains of our children are our most precious economic resource, and we haven’t recognized how vulnerable they are, says Grandjean. We must make protection of the young brain a paramount goal of public health protection. You have only one chance to develop a brain.

To view supplementary documentation on industrial chemicals and risks of toxic effects on brain development, click
http://www.hsph.harvard.edu/neurotoxicant/appendix.doc
Support for this research was provided by the Danish Medical Research Council, the (U.S.) National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency.

See the latest news from the Harvard School of Public Health.

For more information, contact: Todd Datz - tdatz@hsph.harvard.edu - phone: 617-432-3952


Harvard School of Public Health is dedicated to advancing the public's health through learning, discovery, and communication. More than 300 faculty members are engaged in teaching and training the 900-plus student body in a broad spectrum of disciplines crucial to the health and well being of individuals and populations around the world. Programs and projects range from the molecular biology of AIDS vaccines to the epidemiology of cancer; from risk analysis to violence prevention; from maternal and children's health to quality of care measurement; from health care management to international health and human rights.
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Potentials for exposure to industrial chemicals suspected of causing developmental neurotoxicity


Philippe Grandjean, MD, PhD, Adjunct Professor
Marian Perez, MPH, Project Coordinator

Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA


Summary

This brief report has been developed as an appendix to the article, “Developmental Neurotoxicity of Industrial Chemicals – A Silent Pandemic,” by Philippe Grandjean and Philip Landrigan, published in the November 8 online edition of The Lancet. An expanded search for neurotoxic chemicals revealed that 278 additional chemicals are considered to be neurotoxic by the (U.S.) National Institute of Occupational Safety and Health. Even with this addition, the true number of chemicals that have caused damage to the human nervous system is likely much greater.

Most of the 201 neurotoxic chemicals listed in The Lancet article are commonly used. About half of them are considered high-volume production chemicals. Twenty-one are on the top-50 list of compounds from chemical waste and nearly half are priority substances in regard to releases to the environment. Methodological approaches to screening for neurotoxicity have improved only slowly, but new techniques include tests based on cell lines and brain tissue cultures. The risks to brain development caused by neurotoxic chemicals deserve national and international attention, and an action plan needs to be developed.


Known human neurotoxicants

The Lancet paper1 identified 201 chemicals with the ability to cause neurological effects in humans, as described in the peer-reviewed scientific literature. Most of this literature deals with clinical poisoning cases, where the cause was obvious, and where the neurological effects were documented. Some of the literature is based on studies of exposed workers, but very little information is from populations with exposures to chemicals from environmental pollution, because attribution to a single toxic chemical is often impossible.

We have further examined published records from the (U.S.) National Institute of Occupational Safety and Health (NIOSH) on exposure limits for occupational toxicants2. NIOSH provides information on the target organs that are sensitive to these chemicals. By scrutinizing the information on exposure limits, we find that well over 200 substances (not included in The Lancet table) have been assigned an exposure limit to protect against effects that include nervous system damage (often conjointly with effects on other organs). In these cases, NIOSH has considered the evidence sufficient to warn against neurotoxicity if exposure limits are exceeded.

Thus, using less stringent criteria, many additional chemicals with less scientific documentation must be regarded as neurotoxic to humans. The documentation on these substances needs to be further scrutinized and expanded.

Exposures to the known human neurotoxicants

For the chemical compounds listed in The Lancet table, the risks to human health will depend on their likelihood of causing human exposures. The substances have therefore been compared with lists of the chemicals most frequently used in industry and produced in the highest amounts (see table below). The so-called high-volume production (HPV) chemicals (almost 5,000 substances worldwide) are produced in volumes exceeding 1 million pounds per year 3,4,5. Because of their importance in chemical production, they may well cause occupational exposures, releases to the environment, and exposures via consumer products. Almost one-half of the chemicals in The Lancet table are produced in high volumes.

In regard to environmental contamination, the U.S. Environmental Protection Agency (EPA) requires that the release to the environment of certain chemicals (Toxic Release Inventory, TRI) must be reported6. Slightly less than half of the substances included in The Lancet table are also priority substances regarding environmental releases. 

A small number of the chemicals in The Lancet table are now banned, such as polychlorinated biphenyls (PCBs). However, this does not necessarily mean that these substances no longer present a hazard. Twenty-one of the chemicals appear among the top-50 hazardous compounds from chemical waste, selected by the (U.S.) Agency for Toxic Substances and Disease Registry in regard to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)7.


Table 1. Number of industrial chemicals considered toxic to the human brain (total number, 201) and their listing as regulatory agency priorities *


# Listed in Lancet Table # Not listed in Lancet Table Total
HPV 97
 4746
 4843
TRI 93
 488
 581
CERCLA 21
 29
 50

* HPV, high-production volume; CERCLA, Comprehensive Environmental Response, Compensation, and Liability Act; TRI, Toxic Release Inventory

This information suggests that the neurotoxic chemicals in The Lancet table are mostly common chemicals, and very few of them, if any, could be considered laboratory oddities or substances of only historical interest. This finding is noteworthy, because the appearance of human poisoning cases, on which the table was based, may have led to stricter prevention. However, as indicated by The Lancet article, regulations to protect against neurotoxicity, especially developmental neurotoxicity, has usually been delayed.

The majority of the 201 compounds are therefore undoubtedly present in the environment, in food, or in consumer goods. Unfortunately, only a small number of these substances are currently included in biological monitoring efforts, such as those carried out by the (U.S.) Centers for Disease Control (CDC’s most recent National Report on Human Exposure to Environmental Chemicals tested for the presence of 148 chemicals in humans)8. Methods for biological monitoring and other types of exposure assessment are available and, given human exposure to this high number of neurotoxic chemicals, a more inclusive evaluation would seem to deserve immediate attention.


Potential human neurotoxicants

The number of neurotoxic chemicals is likely to be much larger, as indicated by toxicology tests. Twenty years ago, about 750 chemicals had shown neurotoxic effects in laboratory animals9. The number is thought to exceed 1,000 today, although no authoritative estimate of the true number of neurotoxicants is available.

In 1998, the U.S. EPA found that a full set of basic toxicology information was available for only 7% of the HPV chemicals, including developmental/reproductive toxicity. Much of the missing information is now being gathered as part of a multi-national effort. Although developmental toxicity information was available for 654 chemicals (23%), these data may not necessarily include neurotoxicity data beyond crude variables, such as brain weight. Under standard testing conditions, detailed level-3 neurotoxicity testing would be carried out only if indicated by the short-term tests or level-2 testing of subchronic neurotoxicity tests. Although not specifically covered by the U.S.EPA report, very few of the HPV chemicals have apparently been tested this way.

In 1998, the U.S.EPA estimated that developmental neurotoxicity test would cost approximately $150,000. Although this amount is possibly on the low side, better cell-based screening methods have since then been developed that would allow prioritizing of chemicals that need to be examined by full-scale developmental tests.

When a neurotoxicity test shows a positive outcome, a neurotoxic hazard is indicated. In past testing efforts, the proportion of positive tests among substances tested has varied according to the types of chemicals tested10. Perhaps as many as 25% can be expected to show neurotoxic properties. Thus, among the 80,000 to 100,000 chemicals in use worldwide, a substantial number must therefore be suspected of being capable of damaging the human brain, particularly during development. 


The way forward

The incomplete information and the associated uncertainties can easily lead to underestimation of the pandemic of developmental neurotoxicity. Because of the vast societal importance of optimizing human brain development, we propose immediate action to protect the brains of future generations:

1.    Documentation of chemicals that have caused toxic effects on the nervous system in humans to facilitate targeted preventive action against releases of these chemicals;

2.    Documentation of human exposures to neurotoxic chemicals and identification of subgroups at risk due to residence, occupation, diet, and other factors;

3.    Research on the consequences of developmental exposures to neurotoxic chemicals to expand our understanding of the long-term consequences of such exposures; and

4.    Screening for neurotoxicity of commonly used chemicals to identify those that may present a hazard to brain development.
These efforts will require a substantial research effort, investment in safety by commercial enterprise, coordination of prevention by governmental authorities, and international collaboration. We will attempt to initiate and inspire such efforts.


References

1.   Grandjean P, Landrigan PJ. Developmental neurotoxicity of industrial chemicals - A silent pandemic. The Lancet epub 8 Nov 2006
2.  National Institute for Occupational Safety and Health (NIOSH).  Pocket Guide to chemical hazards.  http://www.cdc.gov/Niosh/npg/npgsyn-p.html 
3.  US EPA.  High Production Volume Information System (HPIS). http://www.epa.gov/hpvis/
4.  European Chemical Substances Information System.  European Inventory of Existing  Commercial  Chemical Substances (EINECS) http://ecb.jrc.it/esis/esis.php?PGM=ein
5.  Organization for Economic Co-operation and Development.  The 2004 OECD List of High Production Volume Chemicals. http://www.oecd.org/dataoecd/55/38/33883530.pdf
6.  US EPA.  Toxic Release Inventory Program. http://www.epa.gov/tri/chemical/index.htm
7.  Agency for Toxic Substances & Disease Registry.  2005 CERCLA Priority List of Hazardous Substances.  http://www.atsdr.cdc.gov/cercla/05list.html
8.  Centers for Disease Control and Prevention.  National Report on Human Exposure to Environmental Chemicals.  http://www.cdc.gov/exposurereport/
9.  Anger WK. Neurobehavioral testing of chemicals: impact on recommended standards. Neurobehav Toxicol Teratol 1984; 6: 147-53
10.  Boyes WK. Neurotoxicology and behavior. In: Patty’s Toxicology, 5th ed (Bingham E,  Cohrseen B, Powell CH, eds). New York: Wiley, 2001, pp. 55-121