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Toluene diisocyanate (TDI) is a widely used raw material in the manufacture of flexible polyurethane foams. Acetone (ACE) and/or methylenechloride (MECL) solvents are the most commonly used solvent-based blowing agents for TDI foams. ACGIH has recommended a TWA exposure limit of 5 ppb for TDI and 500 ppm for ACE. For MECL, OSHA mandates a TWA-exposure limit of 25 ppm. This study evaluated the ability of the organic-vapor respirator cartridges (OVC) to block TDI, as well as the effect of airborne MECL or ACE on the OVCs' efficiency to capture TDI. An aluminum/stainless steel exposure chamber was constructed for simultaneously challenging OVCs in triplicate with a dynamic atmosphere of TDI and ACE or MECL vapor. The challenge atmosphere was generated by combining a TDI-laden nitrogen stream from the headspace of a heated impinger with a humidified stream of the indicated solvent in air. The average challenge concentration for TDI was 275 ppb. The average MECL or ACE concentrations were 547 and 581 ppm, respectively. The challenge atmosphere at room temperature (approximately 24 degrees C) and at 25 or 80 percent relative humidity was drawn through each cartridge at 32 L/min for 40+ hours. During the last 8 hours of the challenge, the atmosphere had only TDI vapor. The pre- and post-cartridge atmospheres were periodically sampled for TDI and solvent. Five tests were conducted--two with MSA and three with North OVCs. Under these extreme test conditions no TDI breakthrough was detected from any OVC. The average-calculated efficiency of the OVCs for TDI was99.9+ percent. Within the first 6 hours of the challenge the cartridges were saturated with ACE or MECL; nevertheless, continued challenging with TDI and solvents did not cause any TDI breakthrough. The study demonstrates that with an OSHA-compliant respiratory protection program, an OVC can safely be used for 40 hours in most polyurethane foam operations. In typical occupational environments using TDI and solvents, the solvent breakthrough, rather than TDI breakthrough, would be the determining factor for the calculation of respirator cartridge change-out schedules.

The review of over 800 references on aluminum (Al) published since the mid-fifties covers the occurrence of Al in soil, air, water, plants and food products, as well as air and water pollution problems. In addition, the existing quality criteria, the biology and toxicology of Al, and the therapeutic and medical uses are presented. It is concluded that absorption and retention or accumulation of Al in humans occurs at lower levels of intake than had been assumed formerly. However, levels of 5 to 50 times the normal daily intake do not appear to interfere with other metabolic processes. The adverse effects of Al reported in the more recent years resulted from the inhalation or ingestion of Al in concentrations many times greater than the amounts present under normal circumstances. As in the past, there is still no need for concern by the public or producers of Al or its products concerning hazards to human health derived from well established and extensively used products.

1. King, P.H. et al. Treatment of Waste Sludges From Water Purification Plants. Bulletin 52. Wtr. Resources Res. Ctr., Virginia Polytech. Inst., Blacksburg, Va. (1972). 2. Tabasaran, О. The Dewatering of Digested Sludge Using Synthetic Filtering Aids. Wtr. Res., 5:61 (1971). 3. Sludge Dewatering. WPCF Manual of Practice 20. Corporate Press, Washington, D.C. (1969). 4. Luttrell, M.E. Heating and Aging of Chemical Sludges. MS thesis. Univ. of Missouri-Columbia, Columbia, Mo. I1972). 5. Coackley, P. Laboratory Scale Filtration Experiments and Their Application to Sewage Sludge Dewatering, Biological Treatment of Sewage and Industrial Wastes (Joseph McCabe & W.W. Eckenfelder Jr., editors). Reinhold Publishing Corp., New York, N.Y. (1958). 6. Eckenfelder, W.W. Jr. & O'Connor, D.J. Biological Waste Treatment. Pergamon Press, New York, N.Y. (1961). 7. Wang, L.K. & Shuster, W.W. Polyelectrolyte Determination at Low Concentration. Ind. Engrg. Chem. Prod. Res. Develop., 14:4 (1975). 8. Pulaski, J.C. The Effect of Calcium Ions and pH on the Destabilization of a Dilute Kaolinite Suspension by Synthetic Polymers. MS rprt. Univ. of North Carolina, Chapel Hill, N.C. (1968). 9. O'Melia, C.R. A Review of the Coagulation Process. Public Works, 100:97 (1969). 10. Calkins, R.J. & Novak, J. T. Characterization of Chemical Sludges, /our. AWWA, 65:6:423 (Tun. 1973). 11. Parker, D.G. et al. Biological Conditioning for Improved Sludge Filtration. Jour. WPCF, 44:11:2066 (1972). 12. Montgomery, G.F. The Effect of Chemical Sludge Physical Properties on Sand Bed Dewatering and Drying. MS thesis. Univ. of Missouri-Columbia, Columbia, Mo. (1973). 13. Black, A.P.; Birkner, F.B.; & Morgan, J. J. Destabilization of Dilute Clay Suspensions With Labeled Polymers. Jour. AWWA, 57:12:1547 (Dec. 1965).

Male rats were given single peroral doses of bis(1-14C-2-chloroethyl)ether ([1-14C]BCEE) (40 mg/kg) and of bis(1-14C-2-chloroisopropyl)ether ([1-14C]BCIE) (90 mg/kg). Excretion of 14CO2 and urinary 14C was followed for 48 hr. The time required to eliminate one half of the dose was 12 hr for [1-14C]BCEE and 19 hr for [1-14C]BCIE. In the case of [1-14C]BCEE, expired 14CO2 accounted for 11.5 +/- 5.6(SD)% of the dose, urinary 14C accounted for 64.7 +/- 14.8%, and 2.4 +/- 1.3% was found in the feces. The figures for [1-14C]BCIE were 20.3 +/- 9.4% expired as 14CO2, 47.5 +/- 8.1% as urinary 14C, and 3.8 +/- 0.3% as fecal 14C. Thiodiglycolic acid (TDGA) accounted for roughly 75% of the total urinary 14C collected after the [1-14C]BCEE dose. Lesser metabolites of BCEE were 2-chloroethoxyacetic acid (CEAA) (5%), and N-acetyl-S-[2-(2-chloroethoxy)ethyl]-L-cysteine (ACEEC) (7%). Metabolites of [1-14C]BCIE identified in rat urine were 2-(2-chloro-1-methylethoxy)propanoic acid (CMEPA), roughly 36% of the total urinary 14C, and N-acetyl-S-(2-hydroxypropyl)-L-cysteine (AHPC) at 19%.

Male rats were given a single oral dose (40 mg/kg) of bis(2-chloroethyl)ether (BCEE). Less than 2% of the dose was recovered from the expired air as the unaltered parent compound during an 8-hr collection period. Urine samples representing 48 hr of collection were analyzed by gas chromatography-mass spectrometry. Methyl ester/trimethylsilyl ether derivatives of the isolated urinary acid fraction were prepared for gas-phase analysis. Two metabolites were identified in this fraction: thiodiglycolic acid (TDGA) and 2-chloroethyl β- d -glucosiduronic acid. Quantitative analysis for TDGA gave an average (seven rats) yield for 48 hr of 33 ± 11.8 mg (± SD) of TDGA/kg from a single dose of 40 mg/kg BCEE. The glucuronide of 2-chloroethanol was synthesized using rabbit liver microsomes in an incubation mixture. The matching mass spectrum of the glucuronide prepared in vitro to that identified in the urine of the rats verified 2-chloroethyl β- d -glucosiduronic acid as a metabolite of BCEE.