THE TEN TOXIC TRUTHS
March 3, 2015, by
Professor Marc Cohen
It is widely recognised that the greatest underlying
cause of death among humans today is lifestyle-related chronic
disease. The world is in the grip of an epidemic of obesity,
diabetes, cardiovascular disease, cancer, dementia and more, fuelled by a
high intake of sugar, fat, salt, alcohol and tobacco, and a lack
of physical activity. In addition to this voluntary consumption,
the entire human population is exposed to a toxic cocktail of industrial
chemicals. The impact of industrial chemicals on human health was
recently highlighted by the World Health Organisation, which
forecasts a “tidal wave of cancer” (International Agency for Research
On Cancer 2014). Meanwhile, public health researchers suggest we are
experiencing a “silent pandemic of neuro-developmental disorders” and
a “chemical brain drain” brought about by the exposure of an entire
generation to industrial chemicals (Grandjean 2014). There are many
actions we can take to avoid voluntary and involuntary health risks
and, rather than becoming despondent, we need to become more aware and
vigilant. Since the 16th century when Paracelsus stated “the dose makes
the poison”, this idea has formed the basis for the regulation of
toxic chemicals, including the use of pesticides and pharmaceuticals.
We now know that this truth is incomplete. It is not only the dose, but
also the type of chemical, the timing of exposure, the combination of
chemicals and individual risk factors that combine to produce toxic
effects. These factors give rise to what I call the “10 toxic truths”.
TOXIC TRUTH 1:
Everyone is affected
Since the advent of the Industrial Revolution,
industrial chemicals have permeated the globe and it is clear that
the world will never return to the conditions that existed prior
to this period. Many toxic chemicals are carried throughout the world
dispersed as atmospheric aerosols, while billions of tons of
chemicals and plastics have entered the oceans, resulting in
plastic microparticles being reported in nearly every litre of ocean
water. Toxic chemicals have now entered every habitat and ecosystem
on earth, from the most arid deserts to the deepest seas, and
virtually all living creatures now contain pollutants at or
near harmful levels. Toxic chemical exposure has become an inevitable
part of modern life and everyone is affected. Toxic chemicals are pervasive
in our food, soil, air, water and indoor environments as well as in
all human tissue, including umbilical cord blood and breast milk. Only a
few countries such as the US, Canada and Germany have programs that
aim to monitor toxic chemicals in their general population. The National
Health and Nutrition Examination Survey (NHANES) conducted by the US Centers
for Disease Control and Prevention includes the world’s most comprehensive
assessment of human chemical exposures. The most recent NHANES report examined
only 212 chemicals and found chemicals such as polybrominated diphenyl ethers
(PBDEs), used as fire retardants, and bisphenol A (BPA), a component of epoxy
resins and polycarbonates, in the vast majority of participants (Centers for
Disease Control and Prevention 2009).
TOXIC TRUTH 2:
The full extent is
unknown
While we are all chronically exposed to a toxic
cocktail of industrial pollutants, the full impact of industrial
chemicals on human health remains unknown. There are more than 80,000
industrial chemicals that are commercially produced with more than
3000 produced in high volume and many tens of thousands more
being inadvertently produced from industrial processes. Yet while
the number of industrial chemicals increases every year, in most
cases it is not possible to determine a chemical’s ‘safe level’, or
‘toxicity threshold’. And even when levels are measured, it is often
difficult to interpret their clinical significance. The measurement of the
body’s toxic load is still an emerging science (Sexton 2004,
Committee on Human Biomonitoring for Environmental Toxicants, 2006).
There are very few laboratories that currently have the facilities to
perform comprehensive measures of toxic chemicals and, as yet, there are
no general assessment measures that doctors can request to assess the
‘toxic load’ or ‘body burden’ of their patients. Thus, even though the signs
and symptoms of overdose or overt toxicity are known for some compounds, the
relationship between toxic load, individual susceptibility, clinical symptoms
and chronic disease is incredibly complex and far from understood.
TOXIC TRUTH 3:
Tiny doses can have
big effects
In the past it was thought that dose-response curves
were linear, displaying a direct relationship between dose and toxicity.
It is now known that dose-response curves can be non-linear or
‘non-monotonic’. This occurs when chemicals disturb the body’s
regulatory processes rather than just impacting on target organs or
tissues. By disrupting the endocrine system, the potential to reap
metabolic havoc is greatly increased and extremely small exposures –
orders of magnitude below recognised safety levels – can have
dramatic effects. The hazards of endocrine disrupting chemicals and
their potential for irreversible, latent effects was first brought into
the public spotlight by Theo Colborn and Pete Myers in the mid-1990s with their
book Our Stolen Future. In it they highlighted the science that shows that many
chemicals, which are still being used, can impair reproduction, behaviour, intellectual
capacity and the ability to resist disease in current and future generations. The
book also suggested that: “World-wide exposure to
endocrine disruption has thrust everyone into a large-scale,
unplanned, unintended experiment with health, the outcome of which
may not be known for generations.” While at the time of its
release Our Stolen Future was seen by many as alarmist, a 2013 joint
report from the World Health Organisation and United Nations Environment Program
on the ‘State-of-the-Science of Endocrine Disruptors’ confirms many
of the book’s findings and suggests that exposure to
industrial chemicals with endocrine-disrupting actions are
contributing to the global increase in obesity, cancer,
psychiatric diseases, birth deformities, ADHD and neuro-developmental
problems in children, with current findings being “the tip of the iceberg”.
TOXIC TRUTH 4:
Biomagnification
occurs up the food chain
Many toxic chemicals are fat soluble and last for
decades in the environment where they undergo biomagnification
(tissue concentrations increase) as they pass up the food chain. The
toxicity of DDT and other persistent organic pollutants (POPs) (see
‘The rise of pesticides’ box on page 47) was first brought to the public’s
attention in 1962 by Rachel Carson in her book Silent Spring. In
May 2004, the Stockholm Convention on POPs came into effect, banning
the use of nine of the most dangerous pesticides along with dioxins,
furan and polychlorinated biphenyls (PCBs). These so-called legacy
chemicals were all known to persist in the environment;
undergo long-range environmental transport; be toxic to humans; and
biomagnify up the food chain. Even though the use of most
POP pesticides is banned in agriculture, these chemicals now permeate
the global environment and lodge in the fatty tissue of animals where
they biomagnify millions of times as they travel up the food chain.
Being a precious biological resource, fat is seldom excreted, except for
special situations such as breastfeeding where valuable fat (along
with fat-soluble pollutants) is transferred to infants who sit at the
very top of the food chain. POPs are also absorbed by micro-plastics
in the oceans and are found in high concentrations in marine mammals,
with some beached whales being classified as toxic waste.
TOXIC TRUTH 5:
Chemical cocktails
are synergistic
While exposure to individual toxic chemicals can be
harmful, exposure to chemical mixtures is even more harmful. It has
been shown that chemical cocktails can produce ‘something from nothing’
with toxic mixture effects arising even when the level of each
contaminant in the mixture is below its specific ‘NOAEL’ (no
observable adverse effect limit). Such mixture effects are
not accounted for when determining chemical safety, which is assessed
one chemical at a time, if at all. A 2009 ‘State of the Art Report
on Mixture Toxicity’ commissioned by the European Union found
that “there is consensus in the field of mixture toxicology that
the customary chemical-by-chemical approach to risk assessment might
be too simplistic. It is in danger of underestimating the risk of
chemicals to human health and to the environment.” While mixture toxicity
is currently not accounted for in chemical risk assessments, it
is actively used in pesticide formulations to increase their potency.
In order to kill pests, pesticides contain active ingredients with their own
inherent toxicity, yet when pesticides are packaged and used, they are prepared
as formulations. Pesticide formulations include the addition of often unnamed
and unlabelled adjuvants that are designed to make the active ingredient more
potent by acting as surfactants and cell penetrants. While these so-called
‘inert’ adjuvant chemicals are excluded from safety testing,
recent research suggests they are far from inert and that they
make formulations hundreds of times more toxic than the
active ingredient alone (Mesnage 2014).
TOXIC TRUTH 6:
Bioaccumulation
occurs over the lifespan
Over a human’s lifespan, exposure rates to fat-soluble
chemicals often exceed the excretion rate leading to their
accumulation in fatty tissue. Exposure begins in the womb
with fat-soluble chemicals in umbilical cord blood crossing the
placenta and lodging in foetal fat, which is mainly in the developing brain. A
Canadian report has begun to document the extent to which children are born
“pre-polluted” (Group 2005, WWF 2005, Canada 2013). Throughout a person’s
lifespan, combinations of persistent chemicals accumulate in fatty
tissue such as the brain, breast, prostate and bone marrow, which are
often the tissues that develop cancers in later years. In addition to
persistent fat-soluble chemicals, there are many other water-soluble
endocrine-disrupting chemicals such as BPA and organophosphate (OP)
pesticides that are ingested continually throughout a person’s lifespan,
making them pseudo-persistent.
TOXIC TRUTH 7:
Windows of
development are critical
The toxic effects of chemical exposure during critical
periods, such as early childhood, can be irreversible. This became
tragically evident in the 1970s with the birth of thousands
of children without limbs and other birth defects after being exposed
in utero to thalidomide. More recently, in-utero exposure to OP
pesticides has been shown to impair children’s intellectual development in
later life (see Ref 1).
TOXIC TRUTH 8:
Effects are
trans-generational
Parental exposure to industrial chemicals can affect
offspring and future generations. Many chemicals interfere with
biochemical and endocrine pathways; induce genetic and developmental
abnormalities; and produce trans-generational epigenetic effects that may
lead to abnormalities in the third or fourth generation post-exposure.
This can influence all aspects of an individual’s life history. This
has recently been demonstrated experimentally with a single exposure
to a commonly used fungicide being shown to alter the physiology, behaviour,
metabolic activity and brain development in offspring three
generations later, changing how they perceive and respond to a stress
(see Ref 2).
TOXIC TRUTH 9:
Risk is unequal,
unjust and greater for the young
The health risks of chemical exposures differ according
to individual risk factors that include health status, physiology and
genetics as well as demographic and social differences. Children are most
vulnerable due to their higher dietary exposure, contact with the ground,
hand-to-mouth behaviour, higher metabolic activity, immature organ systems,
longer latency period for developing disease and sensitive development windows so
that exposures lead to lifelong consequences (Landrigan 2005). The US-based
Pesticide Action Network recently published a review of the
scientific literature titled ‘Generation in Jeopardy: How pesticides are
undermining our children’s health and intelligence’, which reports on
the many studies that demonstrate that pesticide exposure compromises
children’s cognitive function and leads to later chronic disease (Schafer
2013).
TOXIC TRUTH 10:
Exposure is unequal
and unjust, and accidents happen
Everyone is exposed to industrial pollutants, yet
exposure risk is not equal. Exposures vary with age, income, education, occupation,
location, lifestyle, public policy and proximity to industrial activity
and accidents. People living in poverty and lower socio-economic
conditions often have the greatest exposure, which then compounds the
effects of wealth inequality (Wright 2009). This makes environmental
justice an important issue. Industrial accidents raise
further justice issues as catastrophic accidents have inadvertently
exposed vast populations of humans and wildlife to industrial pollutants.
These accidents have occurred at every stage of
the chemical-production cycle including mining (BP oil spill);
transport (Exxon Valdez); manufacture (Bhopal); use (Fukushima and Chernobyl);
and disposal (Love Canal). What’s more, often accidents are
associated with minimal, delayed and inadequate compensation
and remediation measures. Here are the detailed references for this
article including ‘Ref 1’ and ‘Ref 2’ for Toxic Truths 7 & 8 respectively.
REFERENCES
·
Ref 1: Bouchard, M., Chevrier, J., Harley, KG.,
Kogut, K., Vedar, M., Calderon, N., Trujillo, C., Johnson, C., Bradman, A.,
Barr, DB., Eskenazi, B. (2011). "Prenatal exposure to organophosphate
pesticides and IQ in 7-year-old children." Environ Health
Perspect 119(8).
·
Ref 2: Crews D, G. R., Scarpino SV, Manikkam M,
Savenkova MI, Skinner MK. (2012). "Epigenetic transgenerational
inheritance of altered stress responses." Proc Natl Acad
Sci 109(23): 9143-9148
·
Baillie-Hamilton (2002). "Chemical toxins:
a hypothesis to explain the global obesity epidemic." J Altern
Complement Med. 2002 Apr;8(2):185-92.
·
Bouchard, M., Chevrier, J., Harley, KG., Kogut,
K., Vedar, M., Calderon, N., Trujillo, C., Johnson, C., Bradman, A., Barr, DB.,
Eskenazi, B. (2011). "Prenatal exposure to organophosphate pesticides and
IQ in 7-year-old children." Environ Health Perspect 119(8).
·
Canada, E. D. (2013). Pre-polluted: A report on
toxic substances in the umbilical cord blood of Canadian newborns. Toronto.
·
Carson, R. (1962). Silent Spring. New York,
Houghton Mifflin.
·
Centers for Disease Control and Prevention
(2009). Fourth National Report on Human Exposure to Environmental Chemicals, US
Department of Health and Human Services Committee on Human Biomonitoring for
Environmental Toxicants. (2006). Human Biomonitoring for Environmental
Chemicals National Research Council
·
Crews D, G. R., Scarpino SV, Manikkam M,
Savenkova MI, Skinner MK. (2012). "Epigenetic transgenerational
inheritance of altered stress responses." Proc Natl Acad
Sci 109(23): 9143-9148
·
Curl, C., Fenske, FA., Elgethun, K. (2003).
"Organophosphorus Pesticide Exposure of Urban and Suburban Preschool
Children with Organic and Conventional Diets." Environmental Health
Perspectives 111(3): 377-382.
·
Grandjean, P., Landrigan, P.J. (2014).
"Neurobehavioural effects of developmental toxicity." The
Lancet 13(3): 330-338.
·
Group, E. W. (2005). Body Burden: The Pollution
in Newborns. Washington, DC.
·
International Agency for Research On Cancer
(2014). World Cancer Report 2014. B. W. Stewart, Wild, C.P.,. Geneva, World
Health Organisation.
·
Krüger, M., Schledorn, P., Schrödl, W., Hoppe,
H.W., Lutz, W., Shehata, A.A., (2014). "Detection of Glyphosate Residues
in Animals and Humans." Journal of Environmental & Analytical
Toxicology 4(2).
·
Landrigan, P., Garg, A. (2005). Children are not
little adults. Children’s health and the environment: A global perspective
- A resource manual for the health sector. J. Pronzczuk de Garbino. Geneva,
World Health Organization.
·
Lu, C. and K. Toepel, Irish, R., Fenske, RA.,
Barr, DB., Bravo, R. (2006). "Organic diets significantly lower children’s
dietary exposure to organophosphorus pesticides." Environ Health
Perspect 114: 260–263.
·
Mesnage, R., Defarge, N., Spiroux de Vendômois,
J., & Séralini, G.-E. (2014). "Major pesticides are more toxic to
human cells than their declared active principles. ." BioMed Research
International: 1-15.
·
Oates, L., Cohen, M., Braun, L., Schembri, A.,
Taskova, R., (2014). "Reduction in Urinary Organophosphate Pesticide
Metabolites in Adults after a Week-Long Organic Diet." Environmental
Research 132: 105-111
·
Schafer, K., Marquez, EC. et al. (2013).
Generation in Jeopardy: How pesticides are undermining our children’s health
and intelligence. Oakland CA, Pesticide Action Network.
·
Sexton, K., Needham, LL., Pirkle, JL. (2004).
"Human Biomonitoring of Environmental Chemicals." American
Scientist 92: 38-45.
·
van der Sluijs, J. P., Simon-Delso, N., Goulson,
D., Maxim, L., Bonmatin, J.M., Belzunces, L.P. (2013). "Neonicotinoids,
bee disorders and the sustainability of pollinator services." Current
Opinion in Environmental Sustainability 5(3-4): 293–305.
·
Vogt, R., D. Bennett, D. Cassady, J. Frost, B.
Ritz and I. Hertz-Picciotto (2012). "Cancer and non-cancer health effects
from food contaminant exposures for children and adults in California: a risk
assessment." Environmental Health 11(1): 83.
·
WHO/UNEP (2013). State of the science of
endocrine disrupting chemicals - 2012: An assessment of the state of the science
of endocrine disruptors prepared by a group of experts for the United Nations
Environment Programme (UNEP) and WHO. Geneva, World health Organisation &
United Nations Environment Program.
·
Wright, R. J. (2009). "Moving towards
making social toxins mainstream in children's environmental
health." Curr Opin Pediatr 21(2): 222-229.
·
WWF, G. (2005). A present for life: hazardous
chemicals in umbilical cord blood. Amsterdam.
·
Zeng, G., Chen, M., Zeng, Z. (2013). "Risks
of Neonicotinoid Pesticides." Science 340: 1403.
The 10 Toxic Truths
- In short form
1) Everyone is
affected
Toxic chemicals are pervasive and are distributed through
long-range environmental transport so that all living things contain pollutants
at or near harmful levels. Toxic chemicals are found in all human tissues and
in food, soil, air, water and indoor environments.
2) The full extent is
unknown
Toxic chemicals are often invisible and have latent effects.
Over 80,000 chemicals are produced commercially and industrial processes
inadvertently create many more. Most chemicals are not tested for toxicity -
and very few are routinely tested for in human tissue.
3) Tiny doses can
have big effects
Dose responses can be non-linear with extremely small doses
of endocrine disrupting chemicals (EDCs) contributing to the global increase in
obesity, birth deformities, cancers, psychiatric diseases and
neurodevelopmental problems with current findings being “the tip of the
iceberg”.
4) Bio-magnification
occurs up the food chain
Persistent organic pollutants (POPs) last for decades in the
environment, accumulate in fatty tissue and magnify up the food-chain.
Bio-magnification leads to much higher concentrations in predatory species and
human infants who sit at the top of the food-chain.
5) Windows of development
are critical
The toxic effects of exposure during critical periods can be
irreversible, yet remain hidden until later in life. Early exposure can impair
intellectual development and metabolism and foster the development of metabolic
syndrome, cancer and other chronic diseases.
6) Effects are
trans-generational
Parental exposure to industrial chemicals affects offspring
and future generations. Industrial chemicals can induce genetic and
developmental abnormalities and transgenerational epigenetic effects that can
lead to abnormalities in the third and fourth generation post-exposure.
7) Chemical cocktails
are synergistic
Exposure to chemical mixtures is more harmful than
individual chemicals. Mixture effects can produce ‘something from nothing’, with
toxicity arising even when individual chemical concentrations have no effect,
yet chemicals are tested for safety individually, if at all.
8) Bioaccumulation
occurs over the lifespan
Exposure rates of fat-soluble chemicals often exceed the
excretion rate leading to accumulation over the lifespan in fatty tissue such
as the brain, breast, prostate and bone marrow. This accumulated body burden
crosses the placenta and targets the fetal brain.
9) Risk is unequal,
unjust and greater for the young
Risks vary with physiology, genetics, demographics and
income. Children are most vulnerable due to higher dietary exposure, contact
with the ground, hand-to-mouth behavior, higher metabolic activity, immature
organ systems and a longer latency period for developing disease.
10) Exposure is
unequal and unjust and accidents happen
Exposure is not equal and varies with age, income,
education, occupation, location, lifestyle, public policy and proximity to
industrial accidents. Accidents that inadvertently expose vast populations to
toxic chemicals happen at every stage of the industrial chemical lifecycle.
Professor Cohen's Ten Toxic Truths article appeared in the March/April 2015 issue of Organic Gardener
magazine.
