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What are the most common routes of exposure to chemicals?
Case ID : 00129

What are the most common routes of exposure to chemicals, and is there any
possibility of fatality resulting from inhalation?

From : Akarasewi, Pasakorn
Last viewed : 17 June 2021 12:37
Viewed : 7662 (times)

Answer from expert #1
The exposure route depends on the chemical, the age of the person and the
circumstances of exposure. Chemical exposures can occur as:
- transplacental
- in breast milk
- via the skin
- by inhalation
- by ingestion, in food or water and via non-nutritive ingestion.

Inhalation exposure can be fatal, depending on the chemical.

Answer from expert #2
The most common routes of exposure are oral, inhalation and dermal. Oral
exposure occurs via food and water, and in children from hand-to-mouth
activities such as sucking toys, and also from eating soil. Inhalation occurs
from vapour and dust in the air. Dermal can arise from a variety of sources such
as air, water and contacting contaminated surfaces.

The extent of exposure by the different routes will vary depending upon the
nature and use of the compound. For fat-soluble compounds, in general,
absorption through the lungs is quite extensive, that via the oral route may be
reduced by metabolism in the liver prior to systemic exposure and dermal is
usually less, the skin providing a barrier to some extent.

Answer from expert #3
The most common routes of exposure to chemicals are through the lungs, through
the gut, and through the skin. Less often considered, but often with serious
consequences are exposures through the eyes and the nose. Inhalation, especially
of narcotic gases, is probably the exposure route most often associated with
acute (rapid) fatality. Worldwide, the greatest cause of chronic (slow) fatality
through lung exposure is probably tobacco smoking.

Answer from expert #4
The three main routes of exposure are ingestion, inhalation and dermal.

For most chemicals, the most common route of exposure is ingestion, which
includes food and drinking water. However, note that "exposure" itself
is the combination of the amount of food or drinking water consumed multiplied
by the concentration of a chemical in the food or drinking water. Estimating
exposure is complicated because different chemicals appear in some foods and not
others and at varying levels. Levels of chemicals in water also vary depending
on the source.

Regarding inhalation, this route of exposure is most important for gases, such
as carbon monoxide and nitrous oxides, but also for suspended particulates.

Again, exposure is due to the volume of air inhaled multiplied by the
concentration of the chemical.

Answer from expert #5
The information has previously been answered by others. There are several
examples for fatality following inhalation. It is all a question about the dose.

Compound specific information can be obtained from the ATSDR webpage.

Answer from expert #6
In addition to the information provided in other answers to this question, it is
important to consider circumstances of exposure when determining the most common
route of exposure to chemicals.

In this context occupational exposure could pose a higher risk compared to some
other situation, unless necessary precautions are properly observed.
Occupational exposure can occur in organized industrial settings where chemicals
are used in the site for associated activities as well as non-industrial
activities such as farmers/applicators using pesticides in fields or
non-occupational exposure such as domestic cooking using firewood, leaking of LP
gas from cooking appliances or use of public health insecticides for domestic
pest control.

Answer from expert #7
The common routes of chemical exposures depend on the physical characteristic of
a chemical. For example if the chemical is volatile then it is easy to inhale
fumes, if it readily absorbed on skin it will enter the human body on touching
and others will cling on hand and food staff and will be ingested. In summary
the common routes of exposures are
1. Ingestion (through mouth)
2. Inhalation (through breathing)
3. Dermal (i.e. through skin)

Answer from expert #8
The most common routes of exposure to chemicals are inhalation, ingestion and

Answer from expert #9
As a general comment, three of the most common routes of exposure are through
the release of chemicals into the air, the water, and the earth/terrestrial
sediments. Humans and other species are exposed to harmful chemicals by
breathing in contaminated air, by drinking/ingesting contaminated water, or by
touching contaminated soil, directly, in their home, their workplace or other
places, or indirectly, by eating foods or touching or otherwise coming into
physical contact with objects that have been contaminated by one or more of
those three routes of exposure.

Answer from expert #10
The nature of the chemical, and its intended use, defines the most probable
route of exposure. For example, volatile chemicals, such as benzene from
automobile exhaust, are typically airborne indicating that the route of exposure
is predominantly inhalation. THMs( trihalomethanes), a common carcinogenic
by-product of chlorination of drinking water, can produce human exposure from
oral ingestion ( from drinking water), from inhalation ( as a volatile chemical
in a warm shower) and from the dermal route ( as in bathing). Pesticide residues
in food typically present exposure opportunities from the oral route (because we
eat foods containing pesticide residues).

In conclusion, there is no single "most common" route of exposure. The
important routes of exposure are defined by the nature of the chemical
(including its physical/chemical properties) and the intended use.