Handbook of Solvents - George Wypych - ChemTech - Ventech!

20
Toxic Effects of Solvent
Exposure
20.1 TOXICOKINETICS, TOXICODYNAMICS, AND TOXICOLOGY
Tilman Hahn, Konrad Botzenhart, Fritz Schweinsberg
Institut f�r Allgemeine Hygiene und Umwelthygiene
Universit�t T�bingen, T�bingen, Germany
20.1.1 TOXICOKINETICS AND TOXICODYNAMICS
20.1.1.1 Exposure
Highest exposures can be found in workplace (e.g., evaporation of solvents) or during special
processes (e.g., leaks of normally closed systems). Acute and severe solvent accidents
often happen in workplaces (high solvent concentrations, intermittent high-level exposures,
high duration of exposure). Apart from working sites, various other emission sources of solvents
should be considered, e.g., consumer products.
The description of exposure parameters (type of solvents, concentrations, duration,
routes of exposure) are important for the evaluation of toxicokinetics. Solvents and other
chemicals are usually emitted as a mixture of various substances. Therefore, the risk assessment
of emitted solvents is difficult to ascertain. 1,2 Solvent concentrations and duration of
exposure vary in most cases (intermittent high-value peaks, periods of low exposure). The
exposure is influenced essentially by surrounding occupational and environmental conditions,
such as working climate, protective equipment and by individual parameters such as
eating habits.
The exposure to solvents is regulated by relevant threshold limit values. 1,2 Exposure
and exposure values can be controlled by defined methods (e.g., ambient and biological
monitoring).
20.1.1.2 Uptake
Relevant uptake routes of solvents are absorption from the lung and percutaneous absorption.
The intestinal uptake is usually caused by accidents or by intent. The absorption rate is
influenced by various factors.