374. Urinary Bromide and Breathing Zone Concentrations of 1-Bromopropane From Workers Exposed to Flexible Foam Spray Adhesives

Abstract

Bromopropane (1-BP) has been marketed as an alternative for ozone depleting solvents and suspect carcinogens and is in aerosol products, adhesives and solvents used for metal, precision and electronics cleaning. Toxicity of 1-BP is poorly understood, but it may be a neurologic, reproductive and hematologic toxin. Sparse exposure information prompted this exposure assessment study using air sampling, and measurement of urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving removal of bromide (Br) from the propyl group. One research objective was to evaluate the utility of urinary Br analysis for assessing 1-BP exposure using a relatively inexpensive, commercially available method. Complete 48 h urine specimens were obtained from 30 workers on two consecutive days at two facilities using 1-BP adhesives to construct polyurethane foam seat cushions and from seven unexposed control subjects. All of the workers' urine was collected into composite samples representing three daily time intervals (at work; after work but before bedtime; and upon wakeup) and analyzed for Br ion by inductively coupled plasma-mass spectrometry. Full-shift breathing zone samples were collected for 1-BP on Anasorb carbon molecular sieve sorbent tubes and analyzed by gas chromatography-flame ionization detection via NIOSH method 1025. Geometric mean (GM) breathing zone concentrations of 1-BP were 92 parts per million (p.p.m.) for adhesive sprayers and 11 p.p.m. for other jobs. For sprayers, urinary Br concentrations ranged from 77 to 542 milligrams per gram of creatinine [mg (g-cr) À1 ] at work; from 58 to 308 mg (g-cr) À1 after work; and from 46 to 672 mg (g-cr) À1 in wake-up samples. Pre-week urinary Br concentrations for sprayers were substantially higher than for the non-sprayers and controls, with GMs of 102, 31 and 3.8 mg (g-cr) À1 , respectively. An association of 48 h urinary Br concentration with 1-BP exposure was statistically significant (r 2 = 0.89) for all jobs combined. This study demonstrates that urinary elimination is an important excretion pathway for 1-BP metabolism, and Br may be a useful biomarker of exposure.

Bromide and N-acetyl-S-(n-propyl)-l-cysteine in urine from workers exposed to 1-bromopropane solvents from vapor degreasing or adhesive manufacturing

“…Geometric mean concentrations and 95% confidence intervals calculated from the urine specimens collected over the sequential time periods at these vapor degreasing plants and at foam cushion factories (Hanley et al 2006) are plotted in Figs. 2 and 3, respectively, for urinary Br cr (-) and AcPrCys cr concentrations.…”

“…Urinary Br (-) elevated substantially above normal (reference value = 10 mg/l) represents accumulated exposure over the previous week or two, as Br (-) is excreted slowly (Jones and Walsh 1979). Hanley et al (2006) demonstrated that urinary Br (-) is an effective biomarker of 1-BP for highly exposed foam cushion workers exposed to spray adhesives [Geometric mean (GM) = 92 ppm for sprayers; GM = 11 ppm for other jobs].…”

NIOSH skin notation (SK) profile: 1-bromopropane [CAS No. 106-94-5].

“…The authors stated that this disparity may be due to the absorption of 1-BP by the skin when the sprayers handled the wet adhesive with bare hands. The results of Hanley et al [2006] indicate that 1-BP may be absorbed via the skin, thus contributing to the systemic dose. Skin Notation Profiles | 1-Bromopropane 4…”

“…Other case reports also detailed nervous system effects [Ichihara et al , 2004a[Ichihara et al , 2004bMajersik et al 2007;Raymond and Ford 2007]. Hanley et al [2006] assessed occupational exposures to 1-BP through air sampling and urinary testing for bromide (Br-) concentrations (a known biomarker of 1-BP exposure) in workers employed as either adhesive sprayers or nonsprayers at foam-fabricating plants that used a spray adhesive containing 1-BP during the manufacture of polyurethane seat cushions. One of the reported findings included a lower than expected correlation between urinary Br-concentration and time-weighted average (TWA) for sprayers, where the mean urinary Br-concentrations for sprayers were approximately 4 times greater than non-sprayers.…”

Making Green Jobs Safe

“…The National Toxicology Program has concluded that exposure to 1-BP is toxic to the developmental and reproductive health of animals 3) . Animal toxicity studies with 1-BP and human case reports of occupational exposures to 1-BP have raised concerns that exposure to 1-BP might cause reproductive and neurologic effects [4][5][6][7][8] . A recent Morbidity and Mortality Weekly Report article highlighted two cases of workers diagnosed with clinical manifestations of neurotoxicity after use of 1-bromopropane in degreasing and dry cleaning operations 9) .…”