From chemosensory thresholds to whole body exposures-experimental approaches evaluating chemosensory effects of chemicals.
OBJECTIVE
To ensure safety and health the avoidance of adverse chemosensory effects is essential at workplaces where volatile chemicals are used. The present study describes psychophysical approaches that provide information for the evaluation of such effects.


METHODS
By means of a modified staircase procedure the odor (OT) and irritation thresholds (IT) of 15 irritants were determined. These basic chemosensory properties, confining the chemosensory effect range, were investigated in a random sample of 144 persons stratified for gender and age. Those irritants exhibiting high chemosensory potency were selected for the second psychophysical part of the study. Forty-eight persons, again stratified for gender and age, rated the intensity of 13 trigeminal and olfactory perceptions elicited by nine ascending concentrations of the irritants, ranging from the odor to the irritation threshold of the respective substances.


RESULTS
Across the investigated chemicals the transition from concentrations eliciting pure olfactory stimulation (OT) to trigeminal stimulation (IT) differed markedly. The carboxylic acids yielded narrow ranges from odor to irritation thresholds, while for the amines (cyclohexylamine, dimethylamine, and trimethylamine) and the esters (ethyl formate and ethyl acetate) these ranges were somewhat wider. The two chemosensory thresholds of ethyl acrylate and ammonia were farthest from each other. Gender and age had only weak impact on the chemosensory thresholds. At present, the results of the intensity ratings could be given for six substances. Among them, the rated pungency for cyclohexylamine, formic acid, and ethyl acetate increased strongest across the nine applied concentrations.


CONCLUSIONS
By means of these psychophysical approaches a diverse class of chemicals can be described and compared with respect to their chemosensory potency. This information can be used twofold (a) for the evaluation of existing studies reporting sensory irritations and (b) for the design of experimental exposure studies.
van Thriel
Christoph
C
Institut für Arbeitsphysiologie an der Universität Dortmund, Leibniz Research Centre for Working Environment and Human Factors, Ardeystr. 67, 44139 Dortmund, Germany. thriel@ifado.de
Schäper
Michael
M
Kiesswetter
Ernst
E
Kleinbeck
Stefan
S
Juran
Stephanie
S
Blaszkewicz
Meinolf
M
Fricke
Hajo-Hennig
HH
Altmann
Lilo
L
Berresheim
Hans
H
Brüning
Thomas
T
D000293:Adolescent; D000328:Adult; D000395:Air Pollutants, Occupational / Q000009:adverse effects* / Q000145:classification; D004056:Differential Threshold; D005260:Female; D006801:Humans; D007509:Irritants / Q000009:adverse effects*; D008297:Male; D008452:Maximum Allowable Concentration; D008875:Middle Aged; D009812:Odorants; D012684:Sensory Thresholds / Q000502:physiology; D017603:Signal Detection, Psychological / Q000502:physiology*; D012903:Smell / Q000502:physiology*; D014276:Trigeminal Nerve / Q000502:physiology*
D000395:Air Pollutants, Occupational; D007509:Irritants