ACUTE AND CHRONIC RESPIRATORY EFFECTS OF SODIUM-BORATE PARTICULATE EXPOSURES

This study examined work-related chronic abnormality in pulmonary func tion and work-related acute irritant symptoms associated with exposure to berate dust in mining and processing operations. Chronic effects w ere examined by pulmonary function at the beginning and end of a 7-yea r interval. Time-specific estimates of sodium berate particulate expos ures were used to estimate cumulative exposure during the study interv al. Change in pulmonary function over the 7 years was found unrelated to the estimate of cumulative exposure during that interval. Exposure- response associations also were examined with respect to short-term pe ak exposures and incidence of five symptoms of acute respiratory irrit ation. Hourly measures of health outcome and continuous measures of pa rticulate exposure were made on each subject throughout the day. Whene ver a subject reported one of the irritant symptoms, a symptom intensi ty score was also recorded along with the approximate time of onset. T he findings indicated that exposure-response relationships were presen t for each of the specific symptoms at several symptom intensity level s. The associations were present when exposure was estimated by both d ay-long and short-term (15-min) time-weighted average exposures. Assoc iations persisted after taking account of smoking, age, and the presen ce of a common cold. No significant difference in response rate was fo und between workers exposed to different types of sodium berate dusts.