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| Тема |
 Some of the health effects of chemicals |
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| Автор | Kalina (Нерегистриран) | |
| Публикувано | 26.01.05 03:15 |
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http://reports.eea.eu.int/NYM2/en/chemicals_eea_unep.pdf
Page 16
Box 5 Some health effects of chemicals
This is a summary of the main health effects of chemicals.
The link with chemicals varies from wellknown causal relationships such as
benzene and leukaemia, to suggestive associations, such as chemical sensitivity and
pesticides.
Most harmful effects are the result of many causes acting together, such as genetics,
lifestyle, radiation, diet, pharmaceuticals, chemicals (manufactured and natural),
smoking and air pollution, including indoor and outdoor exposures. It is also important
to consider sensitive groups, such as the elderly, children, the embryo, the sick, and
pregnant
women, who may be affected at much lower doses than others.
*snip*
Health effect:
Respiratory diseases
Sensitive group:
children, especially
asthmatics
Some associated chemicals:
inhalable particles
sulphur dioxide
nitrogen dioxide
ozone
hydrocarbons
some solvents
terpenes
===========
snippet
timing of exposure to some chemicals is important, particularly for endocrine-disrupting
substances, where exposures during the first 30 days after conception seem to be
critical.
Although exposure to chemicals may be very low for most people
(i.e. in parts per million or trillion of air, water or food), some chemicals at such
low
doses can be potent. For example, estradiol, the body's key oestrogen hormone,
operates at concentrations of parts per trillion- equivalent to one drop of water in 660
"rail tankers" (Brekine, 1997). And some chemicals may be more harmful at lower
doses than at higher doses, since, for example, damaged cells may cause more
harm than dead cells, and higher doses can trigger detoxification activity which is
not triggered by lower doses (Lodovic et al., 1994).
A recent and comprehensive review of the risk assessment of new and existing chemicals
concluded: "At the present level of understanding we cannot adequately predict adverse
effects on ecosystems, nor can we predict what part of the human population will be
affected.
We are only able to assess risks in a very general and simplified manner" (van Leeuwen
et al.,
1996).
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