Handbook of Solvents - George Wypych - ChemTech - Ventech!

20.1 Toxicokinetics, toxicodynamics, and toxicology 1323
IARC 34-36
1: carcinogenic to humans
2A: probably carcinogenic to humans
2B: possibly carcinogenic to humans
3: not classifiable as to its carcinogenicity to humans
NTP 66
K: Known to be a Human Carcinogen
R: Reasonably Anticipated to be a Human Carcinogen (RAHC)
**Notes:
italic: cancer in humans
n.c.: not classified as carcinogenic
n.i.: no information available
n.l.: not listed
BEI: not classified as carcinogenic but biological monitoring is recommended
20.1.2.6 Risk assessment
For risk assessment of solvent exposure, and in addition to factors for general risk assessment
(age, gender, race, diet, physical activity, stress, physical noxes, etc.) it is important to
consider:
• Occupational exposure (high doses) and environmental exposure (low doses) to
solvents separately.
• The effect of exposure time, e. g., life long environmental low exposure or
occupational intermittent high exposure.
• Exposure assessment (generally the most neglected aspect in risk assessment). This
involves extensive ambient monitoring over a long period of time. Only a small
amount of data on biological monitoring of solvents and/or metabolites
(representing the “effective” dose) is available.
• The high volatility of solvents, e. g., VOCs and the fast biotransformation rate (in
the environment and within the human body) for most of the solvents.
• Complex mixtures and numerous sources of environmental exposure.
• Especially for environmental solvent exposure: High-to-low-dose extrapolation for
evaluation of adverse health effects may be misleading.
• Confounding factors, e.g., smoking and alcohol consumption, as adverse health
effects which may dominate in cases of low solvent exposure.
• Risk in this context is defined in terms of the probability as occurrence of a
particular adverse health effect, e. g. 1 in 10 6 .
• Finally, as in general risk assessment, definition of a risk level that is acceptable.
20.1.3 CONCLUSIONS
• For solvent exposure at workplaces considerable amount of evidence for adverse
health effects has been gathered.
• In this regard, specific and carcinogenic effects in particular have been discussed
(see Table 20.1.2 and 20.1.3).
• For environmental solvent exposure only a few examples of adverse health effects
have been documented.
• It is rather unlikely that potentially toxic environmental solvent exposures, e. g.,
benzene or halogenated hydrocarbons, can be prevented in the near future.