Retention of styrene following controlled exposure to constant and fluctuating air concentrations

Abstract

An experiment was designed to determine whether the respiratory retention of styrene vapor, as estimated from measurements of end-exhaled air, was the same during periods of both constant and fluctuating exposure. Six human subjects were exposed to styrene inside a experimental chamber. A computer-controlled system was used to generate time-varying air concentrations of styrene over 4-5h in both multistep sequences of constant exposure (four subjects exposed to 15-99 ppm of styrene in 100-min steps) and fluctuating patterns representative of occupational exposures (two subjects exposed to mean concentrations of styrene of 50 ppm). In the latter case, lognormally distributed exposures, which fit one of two first-order autoregressive models, were generated at intervals of 2.5 min. It was found that the concentration of styrene in end-exhaled air was reduced by about half if the subject inhaled one to three breaths of clean air prior to sampling. This suggests that significant amounts of styrene were desorbed from the lining of the lungs during the initial exhalation. The retention of styrene vapor during constant exposures was 0.935 and was independent of the level. During each of the two sets of fluctuating exposure the retention of styrene was also constant and was independent of both the variance and autocorrelation coefficient. However, the retention of styrene during the fluctuating exposure (estimates ranged from 0.957 to 0.973) was significantly higher than that observed during the constant exposures.(ABSTRACT TRUNCATED AT 250 WORDS)

Environmental and biological monitoring of benzene during self-service automobile refueling.

“…These ratios represent the fractions of the inhaled benzene dose that are exhaled unchanged at steady state (80). The median ratio of alveolar air to inspired air among our subjects was considerably lower at 0.06, again reflecting non-steady-state conditions associated with the short duration of exposure (43,78,81,82) and also reflecting the rapid elimination of benzene following exposure (82,83). Likewise, we suspect that this brief duration of exposure reduced any potential effects of BMI and sex upon benzene in breath, which might have been anticipated due to variation in body fat among subjects (23,25).…”

Exposure assessment for study of olfactory function in workers exposed to styrene in the reinforced‐plastics industry

“…Although animal data and human laboratory data [Berode et al, 1985;Pezzagno et al, 1985;Wieczorek, 1985;Petreas et al, 1995;Nylander-French et al, 1999] suggest that styrene may be readily absorbed through the skin, in the workplace exposure to styrene is primarily via inhalation. Brooks et al [1980] suggest that the polyester resin/styrene complex is sufficiently different from pure styrene test exposures ''that percutaneous absorption of styrene is not an important route of exposure in the reinforcedplastics industry'' [Brooks et al, 1980].…”

Albumin and hemoglobin adducts as biomarkers of exposure to styrene in fiberglass-reinforced-plastics workers

“…In humans, more than 90% of inhaled styrene is retained [13]. Virtually all of the styrene dose is metabolized via cytochrome P450 to the reactive intermediate styrene-7,8-oxide (SO), which is subsequently hydrated via epoxyde hydrolase to styrene glycol and is excreted in the urine as mandelic acid (MA) and phenylglyoxylic acid (PGA).…”