Roundup's Not OK November 2009
Dr Meriel Watts reminds us why we use natural forms of weed control in organic systems, rather than toxic, synthetic chemicals, as she systematically dispels the myth that Roundup is a relatively benign herbicide.
It’s
amazing how many organics people still think it’s OK to just use a
bit of Roundup on those
weeds in the bush or the driveway, or ….
of course, not on the food, but the bush, that’s OK isn’t it?
Well, no, actually it isn’t, and here’s why: Roundup and
various other formulations of the active
ingredient glyphosate, have
the potential to cause serious health and environmental effects, and
have
caused some severe poisoning problems.
Thorough PR by the
developer of Roundup, Monsanto, has resulted in the widespread belief
that
glyphosate is ‘safe’. Registration processes have generally
supported this attitude, and there are no national or international
bans. However, independent scientifi c studies and widespread
poisonings in Latin America resulting from aerial application are
beginning to reveal the true effects of the world’s most widely
used herbicide.
Glyphosate
is sprayed on numerous crops and plantations, including nearly 80% of
genetically modified (GM) crops (canola, corn, cotton, soybean,
sugar beet), with relatively high levels permitted as residues in
food and animal feed.
Poisonings
and symptoms
Glyphosate
herbicides have been frequently used in suicide attempts, resulting
in many deaths, especially in Asia. There have also been many cases
of unintentional poisonings amongst users and bystanders. Widespread
poisonings have occurred in Latin America as a result of aerial
spraying of GM soybean crops, and of coca crops in Colombia, effects
being recorded as far as 10 km away from the supposed spray zone. The
coca spraying has also resulted in widespread animal deaths and food
crop losses.
Symptoms of
poisoning commonly reported from unintentional exposure include
vomiting, diarrhoea, abdominal pain, gastrointestinal infections,
itchy or burning skin, skin rashes and infections (particularly
prevalent in children), blisters, burning or weeping eyes, blurred
vision, conjunctivitis, headaches, fever, rapid heartbeat,
palpitations, raised blood pressure, dizziness, chest pains,
numbness, insomnia, depression, debilitation, difficulty in
breathing, respiratory infections, dry cough, sore throat, and
unpleasant taste in the mouth.
Other effects
reported include balance disorder; reduced cognitive capacity;
seizures; impaired vision, smell, hearing and taste; drop in blood
pressure; twitches and tics; muscle paralysis; peripheral neuropathy;
loss of gross and fine motor skills; excessive sweating; and severe
fatigue.
Acute
toxicity
Glyphosate
has a low toxicity rating (WHO Table 5) despite the substantial
evidence of adverse health effects. Surfactants added to formulated
glyphosate products may be more toxic: the surfactant POEA in Roundup
is 2–3 times more toxic than the glyphosate itself. There are a
number of other chemicals added to glyphosate formulations or
contaminating them; some are known to be harmful, but many are
regarded as trade secrets and it is unknown which might be
contributing to the health effects.
Long-term
toxicity
Recently
scientists have found harmful effects on human cells at levels of
glyphosate too low to have a herbicidal effect, some at levels
similar to those found in food. These effects are amplified by the
adjuvants in the Roundup formulation, which assist penetration of the
cells by glyphosate. Several researchers have reported that
glyphosate appears to accumulate in human cells.
Cancer,
genotoxicity, endocrine disruption, reproduction
The
International Programme on Chemical Safety (IPCS) and the United
States Environmental Protection Agency (US EPA) have declared that
glyphosate is not carcinogenic to humans. The US EPA originally
classifi ed glyphosate as a Group C ‘possible human carcinogen’,
then re-classifi ed it as Group D ‘not classifi able as to human
carcinogenicity’, then as Group E ‘evidence of noncarcinogenicity
in humans’, and then in 2006 rephrased this as ‘Group E
carcinogen with no evidence of human carcinogenicity’.
Yet there is
substantial laboratory and some epidemiological evidence that points
to the opposite conclusion. Some researchers have concluded that
glyphosate and its formulations clearly present a risk of
carcinogenic, mutagenic, and reproductive effects on human cells.
Numerous laboratory
studies have shown that glyphosate and the Roundup formulation can be
genotoxic and endocrine disrupting. One study summarises these
effects occurring at doses substantially lower than those used in
agriculture, or permitted as residues: at 0.5 mg/kg (40 times lower
than levels permitted in soybeans in the US) they were
anti-androgenic; at 1 mg/kg they disrupted the enzyme aromatase; at 2
mg/kg they were anti-oestrogenic; at 5 mg/kg they damaged DNA, and at
10 mg/kg there were cytotoxic. These effects can result in crucial
outcomes for sexual and other cell differentiation, bone metabolism,
liver metabolism, reproduction, development and behaviour, and
hormone dependent diseases such as breast and prostate cancer.
Studies have
demonstrated that glyphosate and/or Roundup cause genetic damage in
human lymphocytes and liver cells; bovine lymphocytes; mouse bone
marrow, liver, and kidney cells; fish gill cells and erythrocytes;
caiman erythrocytes; tadpoles; sea urchin embryos; fruit flies;
root-tip cells of onions; and in Salmonella bacteria. Other
studies have shown that it causes oxidative stress, cell-cycle
dysfunction, and disruption to RNA transcription, all of which can
contribute to carcinogenicity.
Laboratory studies
have shown that very low levels of glyphosate, Roundup, POEA, and the
metabolite AMPA all kill human umbilical, embryonic and placental
cells. Roundup can reduce sperm numbers, increase abnormal sperm,
retard skeletal development, and cause deformities in amphibian
embryos.
Exposure
to glyphosate-based herbicides, even at very low doses may result in
reproductive and hormonal problems, miscarriages, low birth weights,
birth defects, and various cancers, especially haematological cancers
such as non-Hodgkin’s lymphoma and hormonal cancers such as breast
cancer.
Several
epidemiological studies have linked exposure to glyphosate with
non-Hodgkin’s lymphoma, hairy cell leukaemia, multiple myeloma, DNA
damage; and one study with spontaneous abortions and pre-term
deliveries.
Neurological
and other effects
Glyphosate
is assumed by regulators to have no neurological effects – the US
EPA did not require neurotoxicity studies to be carried out for the
registration of Roundup. However there is emerging evidence that
glyphosate can affect the nervous system, and in particular areas of
the brain associated with Parkinson’s disease. In one case study
glyphosate exposure was linked to ‘symmetrical parkinsonian
syndrome’. An epidemiological study of children identified a link
with Attention Hyperactivity Deficit Disorder (ADHD).
Glyphosate damages
liver cells and interferes with a number of enzymes important in
metabolism.
| Left: A boy in Colombia suffering from skin damage on his face as a result of exposure to Roundup Ultra. |
Environmental
effects: Water
The
environmental effects of glyphosate of greatest concern are those
that occur at a subtle level, and can result in significant
disruption of aquatic and terrestrial ecosystems, including
the agroecosystem.
Glyphosate
is water soluble and increasingly found in the environment at levels
that have caused signifi cant effects on species that underpin the
entire aquatic food chain.
Glyphosate
and/or Roundup can alter the composition of natural aquatic
communities, potentially tipping the ecological balance and giving
rise to harmful algal blooms. It can have profound impacts on
microorganisms, plankton, algae and amphibia at low concentrations:
one study showed a 70% reduction in tadpole species and a 40%
increase in algae.
Insects,
crustaceans, molluscs, sea urchins, reptiles, tadpoles, and fi sh can
all be affected, with vulnerability within each group varying
dramatically between species. Effects include reproductive
abnormalities, developmental abnormalities and malformations, DNA
damage, immune effects, oxidative stress, modified enzyme activity,
decreased capacity to cope with stress and maintain homeostasis,
altered behaviour, and impaired olfaction that can threaten their
survival. Amphibians are particularly vulnerable. Roundup is
generally more toxic than glyphosate, especially to fish.
Environmental
effects: Soil and plant health
As
with the aquatic environment, it is the subtle effects causing
disruption of the ecosystem that are of greatest concern,
particularly effects on the agroecosystem. Glyphosate is toxic to
some but not all soil microorganisms, altering microbial community
dynamics in ways that are harmful to plants and to ecological
balance. It increases microorganisms capable of metabolising the
chemical.
It can reduce some
beneficial organisms such as saprophytic fungi that decompose dead
plant material and are important for soil fertility. Numerous studies
have shown that glyphosate stimulates the growth of a number of
fungal pathogens that cause diseases in many crops.
The
upsurge in use of glyphosate in no-till agriculture has brought about
a resurgence of some diseases. Glyphosate binds micronutrients in the
soil and causes micronutrient deficiencies
in plants that increase their susceptibility to
disease, decrease their vigour, and produce micronutrient-deficient
food crops. It can reduce the plant’s production of lignin and
phenolic compounds, which are also important for disease resistance.
It can reduce nitrogen fixation in legumes such as soybean.
Glyphosate can alter
the nutritional composition of foods, for example the protein and
fatty acid content of soybeans. It can cause iron deficiency in
soybeans, which is a concern for human health as human iron defi
ciency is widespread.
Lifeless strips of brown earth |
Effects
on earthworms and beneficial insects Residues
in soil
Residues
in water |
Resistance
Fourteen
weeds in 14 countries have developed resistance to glyphosate. Most
of this resistance is has been caused by the repeated use of
glyphosate in GM crops and no-till agriculture. Some has resulted
from a gradual evolution of exposed weed species, some from gene flow
from GM crops to weed relatives. The later
has been observed with sugar beet in France, canola in Canada,
creeping bentgrass in USA, and also with corn and soybean. Now even
Monsanto is recommending the use of other herbicides in addition to
glyphosate in Roundup-Ready crops to slow the onset of resistance in
weeds.
Climate
change effects
A
number of glyphosate’s adverse effects can be expected to increase
with climate change: higher temperatures enhance glyphosate’s
reduction of chlorophyll and carotenoids in freshwater green algae, increase
toxicity to fish, and increase susceptibility to Fusarium
head
scab in cereals.
To print out a PDF of this article please click
Dr
Meriel Watts is a scientist with Pesticide
Action Network (PAN) Asia & the Pacific, and Coordinator
of PAN Aotearoa NZ.
This article is based on a recently completed
monograph which is available on the PAN AP website www.panap.net
Dr
Meriel Watts can be contacted at: merielwatts@xtra.co.nz
To
see the complete monograph and all references, please see: This
article was originally published by: ORGANIC
NZ November/December
2009
http://www.panap.net/uploads/media/monograph_glyphosate.pdf
www.organicnz.org
