PRINCIPLES OF TOXICOLOGY

384 PROPERTIES AND EFFECTS OF ORGANIC SOLVENTS
Figure 16.7 Ethylene glycol.
nose, and throat irritation; vertigo; headache; drowsiness; contact dermatitis; and corneal inflammation.
No systemic effects from n-butanol typically occur at exposures less than 100 ppm. Skin irritation
is common from allyl alcohol and absorption through the skin can lead to deep pain. It may cause
severe burns of the eye and other ocular symptoms include lacrimation, photophobia, and blurring
vision. Allyl alcohol is metabolized by the liver to allyl aldehyde, a potent hepatotoxin.
The alcohols may interact in industrial circumstances with chlorinated solvents to enhance toxicity
that would occur from either group (potentiation and synergism).
Glycols
The larger alkyl-chain glycols (e.g., some of the dihydroxy alcohols) typically exhibit a lower degree
of acute oral toxicity in comparison to the monohydroxy alcohols. They are not significantly irritating
to eyes or skin, and have vapor pressures that are sufficiently low so that toxic air concentrations are
not usually observed at ambient temperature (e.g., 60–80 °F). Ethylene glycol (see Figure 16.7) is a
common example that may be used to represent the glycol family. A single oral dose on the order of
100 mL is lethal in humans, because of its metabolism to oxalate (or oxalic acid) which is toxic to
the kidneys and may cause obstructive renal failure from formation of oxalate crystals. As in the case
of methanol, ethanol can be used as a competitive inhibitor of ethylene glycol toxicity by blocking
the aldehyde dehydrogenase-mediated metabolism.
16.7 TOXIC PROPERTIES OF REPRESENTATIVE PHENOLS
The aromatic alcohols (also termed phenols), in which the hydroxyl group is attached to a benzene
ring, have the ability to denature and to precipitate proteins in a manner similar to their that of aliphatic
counterparts. This property makes phenol useful as a bacteriostatic agent at concentrations exceeding
0.2 percent and an effective bactericide at concentrations in excess of 1.0 percent. However, it also
renders these compounds quite corrosive and severe burns may result from direct contact. Fatalities
have resulted in individuals inadvertently splashed with liquid phenol. Phenolic compounds also
exhibit limited local anesthetic properties (hence their use in over the counter throat lozenges) and,
in general, are CNS depressants at high concentrations.
Dihydroxy aromatics act like simple phenols but their effects are largely limited to local irritation. The
trihydroxy compounds may reduce the oxygen content of blood at sufficient exposure levels. Methyl phenols
(or cresols), while widely used in industrial applications, typically do not pose a significant inhalation hazard
due to their relatively low vapor pressure and objectionable odor. Their physiological effects are similar to
those of phenol, and dermal exposure, if prolonged, may result in significant absorption, even to the extent
that fatalities have been reported from such exposures. Chlorinated phenols are strong irritants and exhibit
significant oral toxicity because of their direct inhibition of cellular respiration. They also may produce
muscle tremors, weakness, and, in overdose, convulsions, coma, and death.
Phenol (see Figure 16.8) can be cytotoxic to cells and tissues on sufficient exposure, given the
ability to complex with and denature proteins. Because it is easily absorbed and it forms a loose
complex with proteins, phenol may quickly penetrate the skin and underlying tissue, causing deep
burns and tissue necrosis. This penetrating capacity, coupled with its nonspecific toxicity, renders it a
serious handling hazard and all routes of exposure should be controlled carefully. If splashed on the