Safety
26
Absorption Rates
Compared to forearm, which is 1.0
Abdomen
2.1
Palm
1.3
Scalp
3.7
Forehead
4.2
Genital area
11.8
Ball of foot
1.6
Ear canal
5.4
Forearm
1.0
group of test animals. For example, if a pesticide has
an oral LD
50
value of 10 mg/kg and the test animals
each weigh 1 kg, 50 per cent of the animals would die
of poisoning if each ate 10 mg of the pesticide.
The smaller the LD
50
value, the more toxic
the pesticide. The LD
50
value usually refers to the
active ingredient in the pesticide formulation. In this
publication, the LD
50
of the formulated product is also
given when available.
Symptoms of Poisoning
Pesticide poisoning can be acute (due to a single,
large dose, like an accident) or chronic (due to
continued exposure over a long period). For
example, chronic health problems may develop
after long term exposure to pesticides low in
toxicity. Accidental contact with a pesticide,
however, will not necessarily lead to poisoning.
Both types of poisoning can exhibit mild,
moderate or severe symptoms as follows:
Mild poisoning symptoms: Mild symptoms
may be vague and can be compared with a
sickness such as influenza. Typical symptoms
include nausea, headache, tightness of chest, loss
of appetite and stomach cramps. These
symptoms can be immediate or be delayed by 12
to 24 hours.
Moderate poisoning symptoms: These
symptoms are usually more pronounced than
mild symptoms. They include nausea, trembling,
lack of muscle co-ordination, excessive saliva,
blurring of vision, tightness of chest, difficulty
in breathing, flushed or yellow skin, abdominal
cramps, vomiting, diarrhea, tearing from eyes,
profound weakness, rapid pulse and cough.
Severe poisoning symptoms: Severe
symptoms are often more specific and require
immediate hospital treatment. They include
vomiting, diarrhea, excessive sweating, inability
to breathe, convulsions, fever, intense thirst and
coma. It is imperative to reduce exposure when
using all pesticides whether they are highly toxic
or have very low toxicities.
Reducing the Risk of Exposure
to Pesticides
Pesticides may enter the body through the skin
(
dermally), the mouth (orally) or the nose (inhalation).
Skin
Absorption through the skin is the most common
route of exposure. Different areas of the body absorb
pesticides at different rates. For example, assuming the
forearm is given an absorption rate of 1.0, the relative
absorption rate of pesticides in the ear canal is 5.4, on
the scalp 3.7, on the forehead 4.2 and the genital area
11.8 –
almost 12 times greater than the forearm.
The genital area and the head are the areas where
absorption is the greatest.