Persistent Organic Pollutants and Heavy Metals (Including Mercury) - The Changing Arctic Environment: The Arctic Messenger - page 129

magnification characteristic, you will begin to glimpse where this tale is
heading. We will return to the adage from Paracelsus when we notice that a
fair portion of the chronic toxicity of organochlorines and related substances
may be because they are interfering with hormones and that the effect may
depend more on when an animal is exposed rather than on the dose itself.
Figure 8.1
Arctic marine food web
One final point about toxicity. We noticed earlier that organochlorines do not “want” to
degrade. This is not quite true. Several do undergo some transformation (especially in bio-
logical systems), but unfortunately, this often results in substances (residues) with similar
or higher toxic properties that resist any further degradation.
4. Organochlorines are said to be semivolatile. Some of us would explain this
property in terms of its vapour pressure, while a more exacting chemical en-