Document Detail

Chemesthetic responses to airborne mineral dusts: boric acid compared to alkaline materials.
MedLine Citation:
PMID:  17609973     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: (1) To assess the relation between occupationally relevant exposures to dust of boric acid and magnitude of feel in the eye, nose, and throat during activity (pedaling) equal to light industrial work. (2) To compare feel from the dust of boric acid with that of the alkaline dusts calcium oxide and sodium tetraborate pentahydrate (sodium borate). (3) To chart how magnitude of feel changes with time in exposures up to 3/4 h. METHODS: Twelve subjects, six males and six females, participated in duplicate sessions of exposure to 2.5, 5, and 10 mg m(-3) of boric acid, 10 mg m(-3) of sodium borate, 2.5 mg m(-3) of calcium oxide presented as calcium oxide alone or diluted with hydrated calcium sulfate, and 0 mg m(-3) (blank). Exposures occurred in a plastic dome suspended over the head and closed around the neck with rubber dam. Measurements pre- and post-exposure included nasal secretion and nasal resistance. Measurements during exposure included rated magnitude of feel in the eye, nose, and throat, and respiration (Respitrace System). Six concentrations of carbon dioxide ranging from just below detectable to sharply stinging gave subjects references for their ratings. RESULTS: In general, feel increased for periods up to half an hour, then either declined or held at a plateau. Each material had a temporal signature. The nose led with the highest feel, followed by the throat, then the eyes. This hierarchy proved weakest for boric acid; at one level of exposure, magnitude in the throat overtook that in the nose. Accompanying measures implied that change of feel with time occurred neither because of an increase in dilution of the dissolved dusts in newly secreted mucus nor an increase of consequence in nasal resistance. Most likely, sensory adaptation determined the change. Boric acid of 10 mg m(-3) fell slightly and insignificantly below 10 mg m(-3) sodium borate in feel. Boric acid, though, showed a relatively flat dose-response relationship, i.e., a change in level caused little change in feel. CONCLUSIONS: The time-constant for feel from dusts lies on the order of tens of minutes. A flat concentration-response function for boric acid and a notable response from the throat suggests that perceived dryness, not mediated by acidity but perhaps by osmotic pressure, may account for the feel evoked at levels of exposure at or below 10 mg m(-3). More acidic dusts that could actually change nasal pH may trigger sensations differently.
William S Cain; Alfredo A Jalowayski; Roland Schmidt; Michael Kleinman; Kevin Magruder; K C Lee; B Dwight Culver
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-07-03
Journal Detail:
Title:  International archives of occupational and environmental health     Volume:  81     ISSN:  0340-0131     ISO Abbreviation:  Int Arch Occup Environ Health     Publication Date:  2008 Jan 
Date Detail:
Created Date:  2007-11-23     Completed Date:  2008-07-31     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7512134     Medline TA:  Int Arch Occup Environ Health     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  337-45     Citation Subset:  IM    
Chemosensory Perception Laboratory, Department of Surgery (Otolaryngology), University of California, San Diego, La Jolla, CA 92093-0957, USA.
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MeSH Terms
Air Pollutants, Occupational / adverse effects*
Borates / administration & dosage,  adverse effects*
Boric Acids / administration & dosage,  adverse effects*
Calcium Compounds / administration & dosage,  adverse effects*
Ear, Inner / physiopathology
Exercise Test
Nose / physiopathology
Occupational Exposure / adverse effects*
Oxides / administration & dosage,  adverse effects*
Pharynx / physiopathology
Reg. No./Substance:
0/Air Pollutants, Occupational; 0/Borates; 0/Boric Acids; 0/Calcium Compounds; 0/Dust; 0/Oxides; 11113-50-1/boric acid; 1305-78-8/lime; 1330-43-4/sodium borate

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