Degradation of polyurethane foams used in the Même breast implant.

The release of toluene diisocyanate derivatives from polyurethane foam covers that were removed from the Même breast implant was studied. The polyurethane foam covers as retrieved from the implants were contaminated on average with 2,4- and 2,6-toluene diamine (TDA), 2,4- and 2,6-toluene diisocyanate (TDI), and toluene isocyanate amine (TIA) at the 1086 ppm level (combined TDA, TDI, and TIA). When cleaned foam was incubated in Ringer's solution at 37 degrees C for periods ranging from 6-35 days, 4.6 ppm/day of TDA, TDI, and TIA (combined) was formed; the projected annual degradation rate of the foam under these conditions was estimated to be about 0.8%. When cleaned foam was incubated dry at 37 degrees C, 1.5 ppm/day of TDA, TDI, and TIA (combined) was produced. Hence, the polyurethane foam covers used in the Même breast implants are susceptible to both thermal and hydrolytic degradation under simulated physiological conditions.

Comparative metabolism of phenanthrene in the rat and guinea pig.

In the present study the biotransformation of phenanthrene in the rat and guinea pig was investigated. 14C-labelled phenanthrene was administered by gavage in corn oil to Sprague-Dawley rats (10 mg/kg b.w./day) and guinea pigs (10 mg/kg b.w./day). Urine and feces were separately collected for the determination of the radioactivity content, and pooled urine was used for the analysis of metabolites. Phenanthrene was metabolized by the rat and guinea pig to free hydroxylated phenanthrenes and their conjugates. The percentages of conjugates, expressed as the total urinary radioactivity, were 39% glucuronides, 24% sulfates and 18% cysteinylglycine for rats; and 39% glucuronides, 23% sulfates and 28% cysteinylglycine for guinea pigs. Enzymatic hydrolysis of glucuronides and sulfates resulted in the formation of free 1,2-, 3,4- and 9,10-dihydrodiols of phenanthrene and 1-, 2-, 3-, and 4-hydroxyphenanthrene in both species.

Use of a moving-belt interface for on-line high-performance liquid chromatography/mass spectrometry characterization of polycyclic aromatic compounds of molecular weight up to 580 Da in environmental samples.

The applicability of the moving belt high-performance liquid chromatography/mass spectrometry (HPLC/MS) interface to the analysis of high molecular weight polycyclic aromatic compounds (PACs) in a complex sample derived from coal tar is investigated. This interface provides good preservation of chromatographic integrity and useful electron ionization spectra of thermally stable PACs of low to moderate volatility up to molecular masses of at least 580 Da. It is concluded that this HPLC/MS technique will be useful in the analysis of such complex samples, provided a large enough suite of standard compounds can be made available.

Dermal absorption of the insect repellent DEET (N,N-diethyl-m-toluamide) in rats and monkeys: effect of anatomical site and multiple exposure.

The dermal absorption of 14C-ring-labeled DEET (N,N-diethyl-m-toluamide) applied in acetone to the skin of Sprague-Dawley rats and rhesus monkeys for 24 h was determined. Absorption in rats dosed middorsally was 36 +/- 8% with a urinary excretion half-life (t1/2) of 20 h. Both the extent and rate of absorption in monkeys were highly dependent on anatomic site, with 14 +/- 5% (t1/2 = 4 h) penetrating the forearm, 33 +/- 11% (t1/2 = 6 h) the forehead, 27 +/- 3% (t1/2 = 7 h) the dorsal forepaw, and 68 +/- 9% (t1/2 = 8 h) the ventral forepaw. Since DEET is commonly applied frequently by the same individual, the effect of multiple exposure was investigated. No significant difference (p greater than or equal to .3) was obtained either between the total percentage absorbed dermally with single (36 +/- 8%; t1/2 = 20 h) as compared with three (31 +/- 5%; t1/2 = 16 h) DEET applications at 2-h intervals to rats, or between single (14 +/- 5%; t1/2 = 4 h) as compared with three (12 +/- 1%; t1/2 = 4 h) applications at 0.5-h intervals to monkey forearm. A DEET metabolite detected in urine 4 h following topical exposure in humans was extractable following either acid (HCl) hydrolysis or urine treatment with beta-glucuronidase and was identified as ethyltoluamide (parent ion 163; base ion 119) following HPLC purification and characterization by GC/MS.

Tissue distribution metabolism and excretion of 2,2',4,4',5-pentachlorodiphenyl ether in the rat.

The tissue distribution, metabolism and excretion of 14C-2,2',4,4',5-pentachlorodiphenyl ether (PCDE) were studied in the rat. Radioactivity was distributed in all tissues examined, with the highest concentrations being found in the fat followed by the skin, liver, kidney and muscle. Most of the radioactivity found in the tissues was due to unchanged PCDE. Decay of PCDE in the blood was fitted to a four-compartment pharmacokinetic model, and the last compartment had a half-life of 5.8 days. A total of 55% and 1.3% of an orally administered dose was excreted in feces and urine, respectively, in 7 days. More than 64% of the fecal radioactivity was due to unchanged PCDE, while hydroxylated PCDE accounted for 23%.

Metabolism of 1,2,3,4-, 1,2,3,5-, and 1,2,4,5-tetrachlorobenzene in the squirrel monkey.

The metabolism of three tetrachlorobenzene isomers (TeCB) was investigated in the squirrel monkey. The animals were administered orally 6 single doses of 14C-labeled 1,2,3,4-, 1,2,4,5-, or 1,2,3,5-tetrachlorobenzene over a 3-wk period at levels ranging from 50 to 100 mg/kg body weight (b.w.) and kept in individual metabolism cages to collect urine and feces for radioassay. Approximately 38% (1,2,3,4-TeCB), 36% (1,2,3,5-TeCB), and 18% (1,2,4,5-TeCB) of the doses were excreted respectively in the feces 48 h postadministration. In monkeys dosed with 1,2,3,4-TeCB, unchanged compound accounted for 50% of the fecal radioactivity; its fecal metabolites were identified as 1,2,4,5-tetrachlorophenol (TeCP, 22%), N-acetyl-S-(2,3,4,5-tetrachlorophenyl) cysteine (18%), 2,3,4,5-tetrachlorophenyl sulfinic acid (3%), 2,3,4-trichlorophenyl methyl sulfide (0.6%), and 2,3,4,5-tetrachlorophenyl methyl sulfide (0.2%). As was the case with 1,2,3,4-TeCB, unchanged compound accounted for more than 50% of the fecal radioactivity found in the monkeys dosed with 1,2,3,5-TeCB. The fecal metabolites of 1,2,3,5-TeCB consisted of 2,3,4,5-TeCP (2%), 2,3,4,6-TeCP (14%), 2,3,5,6-TeCP (9%), and 2,3,5,6-tetrachlorophenyl sulfinic acid (15%). No metabolites were detected in the feces of monkeys dosed with 1,2,4,5-TeCB. While the fecal route represented the major route of excretion for 1,2,3,4-TeCB, the other two isomers were eliminated exclusively in the feces. The above data in the squirrel monkey are different from those obtained with the rat and the rabbit, and demonstrate the different metabolic pathways for the isomers.

Breath analysis by API/MS--human exposure to volatile organic solvents.

The expired breath of subjects, exposed for periods of ca. 90 min to atmospheres artificially contaminated with low levels of methanol, (ca. 100 ppm) toluene (ca. 50 ppm) or tetrachloroethylene, (ca. 50 ppm) was monitored during and after the exposure period using an atmospheric pressure ionization mass spectrometer, fitted with a direct breath analysis system. The retention of solvent by the subjects, estimated from steady state levels in the expired breath, averaged 82% of the inspired level for methanol, 83% for toluene and 87% for tetrachloroethylene. The elimination of unchanged solvent via respiration during the post exposure period followed first order kinetics with mean half life values of 24 min for methanol, 27 min for toluene and 79 min for tetrachloroethylene.

Metabolites of 1,2,3,4-tetrachlorobenzene in monkey urine.

[14C(U)]-Labeled 1,2,3,4-tetrachlorobenzene was administered orally to squirrel monkeys. Urine was collected from these animals, pooled and analyzed for metabolites by thin-layer chromatography, high-performance liquid chromatography, and gas chromatography-mass spectroscopy. N-Acetyl-s-(2,3,4,5-tetrachlorophenyl) cysteine was shown to be the major metabolite and accounted for 85% of the radioactivity found in urine. A minor metabolite was identified as 2,3,4,5-tetrachlorophenol. This study demonstrates for the first time that an N-acetyl cysteine conjugate has been isolated and identified as metabolite of a chlorinated benzene. This pattern of chlorobenzene metabolism is significantly different from the one obtained with the rat and rabbit, where tetrachlorophenols constitute the major metabolites.

Are video display terminals a source of increased PCB concentration in the working atmosphere? One answer.

In response to the question: "Are datascreen terminals a source of increased PCB concentrations in the working atmosphere?" a study of PCB emissions from video display terminals (VDT) was undertaken. Emissions of 2.4 to 8.1 ng PCB/h were observed from VDT located in a building (1) where the mean PCB level in the air was 46 ng PCB/m3 during the test period, whereas no PCB emissions were detected from VDT located in a building (2) where no PCB could be detected in the ambient air. However, both the air and the VDT from building 2 were found to be contaminated with polycyclic aromatic hydrocarbons. We conclude that the observed PCB emissions from VDT are the result of the vapourization of PCB deposited onto the VDT from the PCB contaminated air and do not originate from the electrical components of the VDT.

Metabolism of 1,2,3,4-, 1,2,3,5-, and 1,2,4,5-tetrachlorobenzene in the rat.

Adult male rats were given orally single doses of 14C-labeled 1,2,3,4-, 1,2,3,5-, or 1,2,4,5-tetrachlorobenzene (TCB) at 10 mg/kg body weight, and were housed in individual metabolism cages to collect urine and feces for radioassay. For 1,2,3,4- and 1,2,3,5-TCB, approximately 46-51% of the doses were excreted in urine and feces within 48 h after administration. During the same period only 8% of the administered 1,2,4,5-tetrachlorobenzene was excreted. Analysis of urine indicted that the tetrachlorobenzenes were biotransformed to a number of polar compounds. The metabolites for each of the three TCBs in decreasing order of quantities were as follows: 1,2,3,4-TCB, to 2,3,4,5- and 2,3,4,6-tetrachlorophenol and a trace of tetrachlorothiophenol and 2,3,4-trichlorophenol; 1,2,3,5-TCB, to 2,3,4,6-tetrachlorophenol, isomeric hydroxythrichlorothiophenols, and a trichlorophenol; 1,2,4,5-TCB, to 2,3,5,6-tetrachlorophenol, tetrachloroquinol, and a trichlorophenol.

The tissue distribution, metabolism, and excretion of octachlorostyrene in the rat.

The tissue distribution, metabolism, and elimination of 14C-octachlorostyrene (OCS) were studied in the rat. OCS was absorbed in the gastrointestinal tract after oral administration and distributed in all tissues examined. The highest concentrations were found in fat followed by adrenal glands, skin, and lungs. Decay of radioactivity in the tissues followed first-order kinetics. Approximately 8% of an iv dose was excreted in feces during 7 days after administration, while negligible amounts were found in the urine. More than 90% of the radioactivity in feces was due to the unchanged compound, while pentachlorophenyldichloroacetic acid and heptachlorostyrene in equal proportions accounted for the remaining 10%. A small amount (1%) of the dose was detected in the expired air as carbon dioxide.

Isolation and concentration of organophosphorus pesticides from drinking water at the ng/L level, using macroreticular resin.

A screening method has been developed for determining organophosphorus pesticides at ng/L levels in drinking water. Sixteen organophosphorus pesticides, diazinon, diazinon-oxon, dimethoate, ronnel, beta-phosphamidon, methyl parathion, ethyl parathion, malathion, chlorpyrifos, fenitrothion, ruelene, methidathion, ethion, EPN, phosalone, and phosmet, were extracted by Amberlite XAD-2 resin from 100 and 200 L drinking water previously spiked with these pesticides. The pesticides were eluted from the XAD-2 resin with acetone-hexane (15+85). The concentrated extract was analyzed by gas chromatography using a nitrogen-phosphorus selective detector and by gas chromatography-mass spectrometry using selected ion monitoring. Recoveries at the 10 and 100 ng/L spiking levels were greater than 90%, except recoveries for dimethoate and phosphamidon were 37 and 42%, respectively. The analysis of 300 L Ottawa tap water showed no detectable amounts (less than 1 ng/L) of any of the 16 organophosphorus pesticides.

The determination of polycyclic aromatic hydrocarbons at the ng/L level in Ottawa tap water.

Samples of Ottawa drinking water, collected in January and February 1978 were analysed by Gas Chromatography/Mass Spectrometry (GC/MS) for fifty polycyclic aromatic hydrocarbons (PAH) and five oxygenated polycyclic aromatic hydrocarbons (O-PAH), following extraction of the organic species using Amberlite XAD-2 macroreticular resin. In the January sample, thirty PAHs, ranging in concentration from 0.05 to 14 ng/L with a mean value of 3.8 ng/L and a total weight of 114 ng/L and four O-PAHs, ranging in concentration from 0.10 to 1.8 ng/L with a mean value of 0.91 ng/L and a total weight of 3.7 ng/L, were detected. In the February sample, thirty-six PAHs, ranging in concentration from 0.05 to 8.1 ng/L with a mean value of 1.4 ng/L and a total weight of 50.4 ng/L and five O-PAHs, ranging in concentration from 0.20 to 2.4 ng/L with a mean value of 1.0 ng/L and a total weight of 5.2 ng/L, were detected. Twenty-eight PAHs and four O-pahs were common to the two samples. The use of Amberlite XAD-2 macroreticular resin to extract PAHs from drinking water is shown to be effective, although the recovery of individual PAHs from artificially loaded XAD-2 resin varied from 57 to 100%.

Organochlorine pesticide levels in Ottawa drinking water, 1976.

Duplicate samples of Ottawa drinking water were collected once a month during 1976 and analyzed for organochlorine pesticides. The samples were analyzed by gas chromatography--mass spectrometry, and pesticides were identified by comparing their retention times, coupled with selected ion monitoring, with those of known standards. The pesticides detected and their mean concentrations in parts per trillion were aldrin (0.9), heptachlor epoxide (3), heptachlor (0.6), alpha-BHC (6), gamma-BHC (3), endrin (4), dieldrin (1), o,p'-TDE (1), o.p'-DDT (3), and o,p'-DDE (0.2).