Sensory and associated reactions to mineral dusts: sodium borate, calcium oxide, and calcium sulfate.
Occupational exposure limits (OELs) for irritant dusts have had no quantifiable bases. This study (1) charted chemosensory feel, denoted chemesthesis here, to dusts of calcium oxide (1 to 5 mg/m(3)), sodium tetraborate pentahydrate [sodium borate] (5 to 40 mg/m(3)), and calcium sulfate (10 to 40 mg/m(3)); (2) examined correlates of the chemesthetic sensations; and (3) sought to illuminate the basis for potency. Twelve screened men exercised against a light load while they breathed air in a dome fed with controlled levels of dust for 20 min. Measured parameters included nasal resistance, nasal secretion, minute ventilation, heart rate, blood oxygenation, mucociliary transport time, and chemesthetic magnitude, calibrated to pungency of carbon dioxide. Subjects registered time-dependent feel from exposures principally in the nose, secondarily in the throat, and hardly in the eyes. Calcium oxide had the greatest potency, followed by sodium borate, with calcium sulfate a distant third. Of the physiological parameters, amount of secretion showed the best association with chemesthetic potency. That measure, as well as mucociliary transport time and minute ventilation, went into calculation of mass of dust dissolved into mucus. The calculations indicated that the two alkaline dusts increased in equal molar amounts with time. At equal molar concentrations, they had, to a first approximation, equal chemesthetic magnitude. On the basis of mass concentration in air or dissolved into mucus, calcium oxide and sodium borate differed in potency by a factor just above five, equal to the difference in their molecular weights. This relationship could inform the setting of OELs for a critical effect of irritation.
Cain
William S
WS
Chemosensory Perception Laboratory, Department of Surgery (Otolaryngology), University of California, San Diego, La Jolla, California 92093-0957, USA. wcain@ucsd.edu
Jalowayski
Alfredo A
AA
Kleinman
Michael
M
Lee
Nam-Soo
NS
Lee
Bo-Ryung
BR
Ahn
Byung-Hoon
BH
Magruder
Kevin
K
Schmidt
Roland
R
Hillen
Brian K
BK
Warren
Craig B
CB
Culver
B Dwight
BD
D000293:Adolescent; D000328:Adult; D001881:Borates / Q000009:adverse effects* / Q000032:analysis*; D017610:Calcium Compounds / Q000009:adverse effects* / Q000032:analysis*; D002133:Calcium Sulfate / Q000009:adverse effects* / Q000032:analysis*; D004305:Dose-Response Relationship, Drug; D004391:Dust; D006801:Humans; D019570:Inhalation Exposure; D007509:Irritants / Q000032:analysis / Q000494:pharmacology; D008297:Male; D016273:Occupational Exposure; D010087:Oxides / Q000009:adverse effects* / Q000032:analysis*; D010465:Perception; D014691:Ventilation
D001881:Borates; D017610:Calcium Compounds; D004391:Dust; D007509:Irritants; D010087:Oxides; C010634:sodium borate; C016538:lime; D002133:Calcium Sulfate