Sensory and cognitive effects of acute exposure to hydrogen sulfide.
BACKGROUND
Some epidemiologic studies have reported compromised cognitive and sensory performance among individuals exposed to low concentrations of hydrogen sulfide (H2S).


OBJECTIVE
We hypothesized a dose-response increase in symptom severity and reduction in sensory and cognitive performance in response to controlled H2S exposures.


METHODS
In separate exposure sessions administered in random order over three consecutive weeks, 74 healthy subjects [35 females, 39 males; mean age (+/- SD) = 24.7 +/- 4.2; mean years of education = 16.5 +/- 2.4], were exposed to 0.05, 0.5, and 5 ppm H2S. During each exposure session, subjects completed ratings and tests before H2S exposure (baseline) and during the final hour of the 2-hr exposure period.


RESULTS
Dose-response reduction in air quality and increases in ratings of odor intensity, irritation, and unpleasantness were observed. Total symptom severity was not significantly elevated across any exposure condition, but anxiety symptoms were significantly greater in the 5-ppm than in the 0.05-ppm condition. No dose-response effect was observed for sensory or cognitive measures. Verbal learning was compromised during each exposure condition.


CONCLUSIONS
Although some symptoms increased with exposure, the magnitude of these changes was relatively minor. Increased anxiety was significantly related to ratings of irritation due to odor. Whether the effect on verbal learning represents a threshold effect of H2S or an effect due to fatigue across exposure requires further investigation. These acute effects in a healthy sample cannot be directly generalized to communities where individuals have other health conditions and concomitant exposures.
Fiedler
Nancy
N
Department of Environmental and Occupational Medicine, UMDNJ-Robert Wood Johnson Medical School, 170 Frelinghuysen Rd., Rm. 210, Piscataway, NJ 08854 USA.. nfiedler@eohsi.rutgers.edu <nfiedler@eohsi.rutgers.edu>
Kipen
Howard
H
Ohman-Strickland
Pamela
P
Zhang
Junfeng
J
Weisel
Clifford
C
Laumbach
Robert
R
Kelly-McNeil
Kathie
K
Olejeme
Kelechi
K
Lioy
Paul
P
D000328:Adult; D003071:Cognition / Q000187:drug effects; D005260:Female; D006801:Humans; D006862:Hydrogen Sulfide / Q000633:toxicity*; D019570:Inhalation Exposure / Q000009:adverse effects*; D007509:Irritants / Q000633:toxicity*; D008297:Male; D009812:Odorants; D011187:Posture; D011597:Psychomotor Performance / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D014706:Verbal Learning / Q000187:drug effects*; D014792:Visual Acuity / Q000187:drug effects
D007509:Irritants; D006862:Hydrogen Sulfide