Handbook of Solvents - George Wypych - ChemTech - Ventech!

1318 Tilman Hahn, Konrad Botzenhart, Fritz Schweinsberg
tion of physiological and physicochemical parameters 18 or to assessing low exposures to
complex chemical mixtures. 19
20.1.2 TOXICOLOGY
20.1.2.1 General effects
General effects of solvents concern primarily acute exposures to high solvent
concentrations. Despite some variations of symptoms, the resulting effects on the central
nervous system (CNS) are rather stereotypical. 20
Several solvents have depressant or narcotic effects, and hence, some solvents are
used as anesthetics. 21 The main acute health hazards result from the narcotic effects. Their
intensity is proportional to the solvent concentrations in brain tissue and is caused by the
solvents themselves (physical and chemical interactions with neural membranes, nerve
cells or neurotransmitters of the CNS).
General CNS dysfunctions after solvent exposure, are initially euphoria and
disinhibition, higher exposures result in pre-narcotic symptoms such as dizziness, euphoria,
disorientation and confusion, nausea, headache, vomiting, ataxia, paresthesia, increased
salivation and tachycardia. 22,23 The symptoms are rapidly reversible when the solvents are
removed.
In addition to the non-specific acute narcotic effects of solvents mentioned above, alterations
of behavioral, cognitive and psychomotoric functions are typically found after
short-term exposure to solvent levels close to the TLV. Overexposure leads to convulsions,
coma and death. Typical changes are paresthesias, visual and auditory deficits, cognitive
deficits (short-term and long-term memory loss), confusion, disorientation, affective deficits
(nervousness, irritability, depression, apathy, compulsive behavior) and motor deficits
(weakness in extremities, incoordination, fatigue, tremor). 24,25
It is difficult to develop useful methods and models for testing these behavioral effects
of solvents but for this purpose tests of attention and reaction, cognitive tests and other test
systems are used. 26,27
Acute CNS dysfunction diseases can show mild (organic affective syndrome), moderate
or severe (acute toxic encephalopathy) symptoms. 28,29
Unspecific irritations of skin and mucosa membrane structures can be caused by solvents.
Various solvents are significant occupational irritants, e.g., solvents which cause irritant
contact dermatitis. 30 Intact skin structures can be destroyed by solvents which dissolve
grease and fat. Typically, the dermatitis is characterized by dryness, scaling and fissuring
and is usually located on the hands. It is often caused by handling solvent-contaminated
products or by cleaning procedures. 31,32
Unspecific irritation of mucous membranes is often caused by solvent vapors, e.g., irritation
of the eyes and various sections of the airways.
20.1.2.2 Specific non-immunological effects
Table 20.1.2 summarizes the main specific effects of solvents: 33-47
• Hepatotoxicity
• Nephrotoxicity
• Reproductive toxicity
• Hemopoietic toxicity
• Neurotoxicity
• Ocular toxicity