Journal of Toxicology & Environmental Health Part A: Current Issues

Daiva Meironyte, Koidu Noren, Ake Bergman,

doi: 10.1080/009841099157197pmid: 10580757

A previously described method for analysis of organochlorine compounds in human milk was adopted for analysis of brominated diphenyl ethers ( BDEs) substituted with three to six bromine atom s. Analytes were extracted from hum an milk with the lipophilic gel Lipidex 5000. Further purifications were performed on partly deactivated aluminum oxide and silica gel columns, followed by gel permeation chromatography. The concentrations of BDEs were determined by gas chromatography/mass spectrometry (GC/MS). The average recoveries of 2,2',4-triBDE (BDE-17), 2,4,4'-triBDE (BDE28) , 2,2',4,4'-tetraBDE (BDE-47), 2,3',4,4'-tetraBDE (BDE-66), 2,2',3,4,4'-pentaBDE (BDE-8 5) , 2,2',4,4',5-p entaBDE (BDE-99), 2,2',4,4',6-pentaBDE (BDE-100) , 2,2',4,4',5,5'-hexaBDE (BDE-153), and 2,2',4,4',5,6'-hexaBDE (BDE-154) added to the samples before extraction ranged from 86% to 102% . Pooled samples of breast milk, collected at eight time periods between 1972 and 1997, were analyzed for PBDEs. BDE-47 was the most abundant PBDE congener in all samples. In total, eight PBDE congeners were identified in the milk. The sum of the concentrations of BDE congeners in human milk increased from 0.07 to 4.02 ng/g lipids during the 25-yr period studied.

James M. Antonini, Nicholas J. Lawryk, G. G. Krishna Murthy, Joseph D. Brain,

doi: 10.1080/009841099157205pmid: 10580758

It was shown previously that fumes generated from stainless steel (SS) welding induced more pneumotoxicity and were cleared from the lungs at a slower rate than fumes collected from mild steel (MS) welding. These differences in response may be attributed to the metal composition of SS and MS welding fumes. In this study, fumes with vastly different metal profiles were collected during gas metal arc (GMA) or flux-covered manual metal arc (MMA) welding using two different consumable electrodes, SS or MS. The collected samples were suspended in saline, incubated for 24 h at 37 C, and centrifuged. The supernatant (soluble components) and pellets (insoluble particulates) were separated, and their effects on lung macrophage viability and the release of reactive oxygen species (ROS) by macrophages were examined in vitro. The soluble MMA-SS sample was shown to be the most cytotoxic to macrophages and to have the greatest effect on their function as compared to the GMA-SS and GMA-MS fumes. Neither the soluble nor insoluble forms of the GMA-MS sample had any marked effect on macrophage viability. The flux-covered MMA-SS fume was found to be much more water soluble as compared to either the GMA-SS or the GMA-MS fumes. The soluble fraction of the MMA-SS samples was comprised almost entirely of Cr. The small fraction of the GMA-MS sample that was soluble contained Mn with little Fe, while a more complex mixture was observed in the soluble portion of the GMA-SS sample, which contained Mn, Ni, Fe, Cr, and Cu. Data show that differences in the solubility of welding fumes influence the viability and ROS production of macrophages. The presence of soluble metals, such as Fe, Cr, Ni, Cu, and Mn, and the complexes formed by these different metals are likely important in the pulmonary responses observed after welding fume exposure.

C. Schreiner, Q. Bui, R. Breglia, D. Burnett, F. Koschier, P. Podhasky, E. Lapadula, R. White, R. E. Schroeder,

doi: 10.1080/009841099157214pmid: 10580759

A distillate of light catalytic cracked naphtha (CAS number 64741-55-5, LCCN-D), administered by inhalation, was tested for reproductive and developmental toxicity in Sprague-Dawley rats, following a modified OECD Guideline 421, Reproductive/ Developmental Toxicity Screening Protocol. LCCN-D was administered as a vapor, 6 h/ d, 7 d/wk at target concentrations of 0, 750, 2500 or 7500 ppm to female rats for approximately 7 wk from 2 wk prior to mating, during mating through gestational d 19, and to males beginning 2 wk prior to mating for 8 consecutive weeks. Dams and litters were sacrificed on postnatal d 4, and males were sacrificed within the following week. Parental systemic effects observed at the 7500 ppm exposure level were increased kidney weights and relative liver weights in males and increased spleen weights in highdose females. Livers and spleens from rats in the high-dose group were normal in appearance at necropsy. Increased kidney weights in high-dose males were indicative of male-rat-specific light hydrocarbon nephropathy. No test-related m icroscopic changes were observed in the reproductive organs or nasal turbinate tissues of either sex. Reproductive performance was unaffected by treatment with LCCN-D. Fertility index was 90% in all dose groups. There were no exposure-related differences in implantation sites and live pups per litter, and no gross abnormalities were observed. Pups born from treated dams showed comparable body weights and weight gains to controls. The viability index on postpartum d 4 was 97% ; the high-dose group had more male than female pups at birth and at d 4 postpartum. Under the conditions of this study, the no-observable-adverse-effect level (NOAEL) for exposure to light catalytic cracked naphtha distillate for parental toxicity was 2500 ppm and the NOAEL for reproductive performance and developmental toxicity was 7500 ppm.

Janet M. Firriolo, Felix Ayala-Fierro, I. Glenn Sipes, Dean E. Carter,

doi: 10.1080/009841099157223pmid: 10580760

The absorption and disposition of inorganic cobalt salts after oral administration have not been completely characterized. The objective of this project was to investigate the absorption and disposition of cobalt naphthenate in Fischer 344 rats following a single oral dose. Cobalt naphthenate was given orally at 3 doses: 0.333, 3.33, or 33.3 mg Co(II)/kg. Tissues, urine, and feces were collected over a 36-h period from the low- and high-dose groups; blood was collected from all 3 dose groups. The majority of the dose in both the low- and high-dose groups was excreted in the feces (42% and 73.1% , respectively), indicating that cobalt was incompletely absorbed from the gastrointestinal tract following oral dosing. The percent of the dose excreted in the urine was similar for low and high doses (31.8% and 26.3% , respectively). Cobalt concentrations were found to be highest in the liver and kidneys. The blood versus time cobalt concentration curves for the lowdose, intermediate-dose, and high-dose groups were elevated 4- to 5-fold, 14- to 25-fold, and 25- to 60-fold over control blood levels, respectively. The peak plasma concentrations of 0.6 and 1.7 mug Co(II)/ml occurred at approximately 4.3 h for the intermediatedose group, and 3.3 h for the high-dose group. The terminal elimination half-lives were 24.7 and 24 h for the intermediate- and high-dose groups, respectively. Thus, although the extent of cobalt absorption as indicated by the blood concentrations and areas under the blood-time curves was not proportional to dose, the calculated pharmacokinetic values for the time to peak blood concentration and the apparent elimination rate constants were independent of dose. The amount excreted in the urine was also proportional to the dose. These apparent anomalies were not related to protein binding in blood.