Reducing Exposure is Smart
more that scientists learn about the toxicity of pesticides, the more
questions are raised about the potential toxic effects on people.
Pesticide manufacturers often portray these unresolved scientific
issues, and the uncertainty that comes with them, as safety.
Statements like, "There is no conclusive evidence of harm
from exposure to pesticide X are intended to mislead the public into
believing that exposures to pesticides and toxic chemicals are without
appreciable risks. This is not true. Absence of knowledge is not proof
The endocrine (hormone) system is perhaps even more
toxic exposure than the nervous system, and over the past decade,
enormous effort has been put into the study of how pesticides and toxic
chemicals interfere with normal endocrine signaling and function. A
significant body of research in animals now shows that ultra-low doses
of pesticides and toxic chemicals on critical days of development can
cause changes in hormone function and effects on organ development and
function that often only appear later in life. A growing number of
these studies show that low doses at a susceptible moment of
development can cause more of an effect than high doses (vom Saal 1997,
Alworth 2002, Hayes 2003). This is particularly relevant to childhood
and fetal exposures via food and water where the timing of the exposure
is at least as important as the dose.
pesticides are now considered "endocrine disrupters", in part because
the term is something of a catch phrase for chemicals that cause a
variety of changes in normal hormone signaling. Some better known
examples of highly toxic endocrine disrupting pesticides are DDT (and
its metabolite DDE) which are now known to exhibit much of their
toxicity through anti-androgenic (de-masculinizing) properties (ATSDR
2002), vinclozolin, a heavily used fungicide that is also
anti-androgenic (EPA 2000), endosulfan, a DDT relative with estrogenic
properties that is found more often in food than any other pesticide
(EPA 2002, USDA 1994-2004), and atrazine, a weed killer with broad
hormonal activity, that contaminates the drinking water of about 20
million people in the United States (EWG 1999, EWG 1995).
scientists know much more about how pesticides can change critical
hormone signals in the human body in ways that can have potential life
changing effects. Yet in spite of these advances, there is little
agreement on how much endocrine disruption is too much, and how much is
without harm. The same is true of immune system effects and to a lesser
degree effects on the developing nervous system.
What's the Difference?
EWG simulation of thousands of consumers eating high and low pesticide
diets shows that people can lower their pesticide exposure by almost 90
percent by avoiding the top twelve most contaminated fruits and
vegetables and eating the least contaminated instead. Eating the 12
most contaminated fruits and vegetables will expose a person to about
15 pesticides per day, on average. Eating the 12 least contaminated
will expose a person to less than 2 pesticides per day. Less dramatic
comparisons will produce less dramatic reductions, but without doubt
using the Guide provides people with a way to make choices that lower
pesticide exposure in the diet.
THE DIRTY DOZEN
with two previous EWG investigations, fruits topped the list of the
consistently most contaminated fruits and vegetables, with seven of the
12 most contaminated foods. Among the top six were four fruits, with
peaches leading the list, then apples, nectarines and strawberries.
Cherries, pears, and imported grapes were the other three fruits in the
top 12. Among these seven fruits:
- Nectarines had
the highest percentage of samples test positive for pesticides (97.3
percent), followed by peaches (96.6 percent) and apples (92.1 percent).
- Peaches had the highest likelihood of multiple pesticides
on a single
sample — 86.6 percent had two or more pesticide residues —
nectarines (85.3 percent) and apples (78.9 percent).
bell peppers had the most pesticides detected on a single sample with
eleven pesticides on a single sample, followed by peaches and apples,
where nine pesticides were found on a single sample.
- Peaches had the most pesticides overall with some
combination of up to
42 pesticides found on the samples tested, followed by apples with 37
pesticides strawberries with 35.
peppers, celery, spinach, lettuce, and potatoes are the vegetables most
likely to expose consumers to pesticides. Among these five vegetables:
- Celery had the highest of percentage of samples test
pesticides (94.1 percent), followed by sweet bell peppers (81.5
percent) and potatoes (81.0 percent).
- Celery also had
the highest likelihood of multiple pesticides on a single vegetable
(79.8 percent of samples), followed by sweet bell peppers (62.2
percent) and lettuce (33 percent).
- Sweet bell peppers was
the vegetable with the most pesticides detected on a single sample (11
found on one sample), followed by celery and lettuce (both with nine).
- Sweet bell peppers were the vegetable with the most
pesticides overall with 64, followed by lettuce at 49 and celery with
The vegetables least likely to have pesticides on them are
onions, sweet corn, asparagus, sweet peas, cabbage and broccoli.
three-quarters of the broccoli (71.9 percent), sweet pea (77.1
percent), and cabbage (82.1 percent) samples had no detectable
pesticides. Among the other three vegetables on the least-contaminated
list, there were no detectable residues on 90 percent or more of the
- Multiple pesticide residues are extremely rare on
any of these least contaminated vegetables. Cabbage had the highest
likelihood, with a 4.8 percent chance of more than one pesticide when
ready to eat. Onions and corn both had the lowest chance with zero
samples containing more than one pesticide when eaten.
greatest number of pesticides detected on a single sample of any of
these low-pesticide vegetables was three as compared to 11 found on
sweet bell peppers, the most contaminated crop with the most residues.
and asparagus both had the most pesticides found on a single vegetable
crop at up to 19 pesticides but far fewer than the most contaminated
vegetable, sweet bell peppers, on which 64 were found.
The six fruits least likely to have pesticide residues on them
are avocados, pineapples, mangoes, kiwi, bananas, and papaya.
than 10 percent of pineapple, mango, and avocado samples had detectable
pesticides on them and fewer than one percent of samples had more than
one pesticide residue.
- Though 59 percent of bananas had
detectable pesticides, multiple residues are rare with only 2 percent
of samples containing more than one residue. Kiwi and papaya had
residues on 15.3 percent and 23.5 percent of samples, respectively, and
just 3.4 percent and 5.0 percent of samples, respectively, had multiple