Edwin R. Kinkead

Reproductive Toxicity Screen of 1,3,5-Trinitrobenzene Administered in the Diet of Sprague-Dawley Rats:

Several Army installations targeted for restoration have measurable quantities of 1,3,5-trinitrobenzene (TNB) in the soil and groundwater. As part of the process of developing environmental and health effects criteria for restoration, a modified Screening Information Data Set (SIDS) reproductive study was performed. Male and female Sprague-Dawley rats received a diet containing approximately 30, 150, or 300 mg TNB/kg diet. Mating occurred following 14 days of treatment. All dams, one-half the males, and representative pups were maintained for a total of 90 days of treatment. No mortality occurred during the study; however, a decrease in mean body weights was noted in both sexes of high-dose rats. A dose-related effect was noted in measurements of sperm function/activity. Sperm depletion and degeneration of the seminiferous tubules were noted histopathologically. Methemoglobinemia and splenic hemosiderosis were common findings in the high- and mid-dose levels of both sexes at necropsy. No adverse effects were noted in mating or fertility indices. No significant treatment-related differences were found in length of gestation, sex ratio, gestation index, or mean number of pups per litter.

SUBCHRONIC INHALATION STUDIES ON POLYCHLOROTRIFLUOROETHYLENE (3.1 OIL)

Abstract3.1 Oil, an oligomer of chlorotrifluoroethylene (CTFE), is an inert, nonflammable, saturated and hydrogen-free chlorofluorocarbon oil of interest to the Department of Defense (DOD) as a potential hydraulic fluid. To determine the potential subchronic inhalation toxicity of this CTFE oligomer, male and female F-344 rats were exposed to air only or to 0.25, 0.50, or 1.00 mg/l of CTFE oligomer in 65 6-h inhalation exposures over a 90-day period. A dose-dependent depression in body weight gains was noted in male rats only Serum alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase activities examined at the conclusion of the study indicated a treatment-related effect in the male test rats, but not the female test rats. Notable concentration-related increases (p < .07) in relative kidney and liver weights occurred in both sexes of rats at all test concentrations. The male rats showed slight to minimal hyaline droplet formation in the kidney proximal tubule epithelium. Pronounce...

Effects of a 13-Week Chloropentafluorobenzene Inhalation Exposure of Fischer 344 Rats and B6C3F1 Mice

Chloropentafluorobenzene (CPFB) has been identified as a can didate simulant for nonpersistent chemical warfare agents. Acute toxicity studies have shown that CPFB has limited adverse ef fects on laboratory animals. A 21-day inhalation study of rats and mice to 2.5, 0.8, and 0.25 mg CPFB/liter resulted in re duced weight gain in male and female rats exposed at the high concentration only and identified the liver as a potential target organ. This multiconcentration inhalation study was designed to detect a no-observable-effect level associated with repeated expo sure to CPFB. Male and female rats and mice were exposed to 250, 50, or 10 mg CPFB/m3 (0.25, 0.05, or 0.01 mg CPFB/li ter) for 13 weeks. No treatment-related effects on body weight, clinical chemistries, mortality, absolute or relative organ weight or histopathology were noted.

General Toxicity and Reproductive Screen of Liquid Propellant Xm46 Administered in the Drinking Water of Sprague-Dawley Rats

Liquid propellant XM46 is being considered as a replacement for solid propellants, both as part of a regenerative injection gun system and as a working fluid in an electrothermal gun system. The XM46 formulation contains hydroxylammonium nitrate, triethanolammonium nitrate, and water. Male and female Sprague-Dawley rats received XM46 in drinking water containing 2.0, 1.0, 0.2, or 0.0 g XM46/liter throughout a 90-day study. Mating occurred following 14 days of treatment. One-half the male rats per group were necropsied after 28 days of treatment; the remaining males and all dams were necropsied following 90 days of treatment. No mortality occurred in any of the parental animals during the study. The study did not demonstrate any adverse effects on reproduction or litter parameters. Hemolytic anemia and methemoglobinemia were common in both sexes of rats. Splenomegaly was found in both sexes; in male rats as early as 28 days. Exposures via drinking water containing XM46 for 90 days did not result in any decrease in reproductive performance in male or female rats, but it did result in clinical signs of hemolytic anemia at doses as low as 17 mg/kg/day.

Reproductive Toxicity Screen of Ammonium Dinitramide Administered in the Drinking Water of Sprague-Dawley Rats

The Department of Defense is currently considering replacing ammonium perchlorate with ammonium dinitramide (ADN), a class 1.1 explosive oxidizer to be used in solid rocket propellant mixtures and explosives. This study was intended to evaluate the potential of ADN to produce alterations in paternal fertility, maternal pregnancy and lactation, and growth and development of offspring. Male and female rats received drinking water containing 0.0, 0.2, 1.0, or 2.0 g ADN/liter throughout the study. Mating occurred following 14 days of treatment. All dams, one-half the males, and representative pups were maintained for a total of 90 days of treatment. No mortality occurred in parental animals during the study. Treatment with ADN resulted in no adverse effects on mating; 92-100% of the animals mated. No treatment-related effects were seen in parental animals clinically or histopathologically. Adverse treatment-related effects were noted in maternal and paternal fertility indices, gestational indices, and live birth indices in both the mid- and high-dose groups. Litter sizes in themid- and high-dose groups were significantly smaller than those of the low-dose and control groups. Mean pup weights showed no statistically significant differences between ADN-treated pups and controls. Gross and histopathological examination of the animals failed to identify the cause for the decrease in litter production in the mid- and high-dose dams. This study indicates that ADN is a reproductive toxicant. The no-observable-effect level (NOEL) is 29 mg/kg/day, the median dose of the low-level female rats.

Toxicologic and Oncogenic Potential of JP-4 Vapor: 90-Day Continuous Inhalation Exposure

AbstractMale and female Fischer 344 rats, female C57BU6 mice, and male and female beagle dogs were divided into three treatment groups and exposed nearly continuously (23 h/day, 7 days/wk) to IP-4 jet fuel vapor at concentrations of 0, 500, and 1000 mg/m3 for 90 days. At exposure termination, all dogs and one-third of the rodents were euthanized and the remaining animals were held for either a 19- or 21 -mo postexposure tumorigenesis observation period. Pathologic findings in male rats revealed treatment-related renal toxicity consistent with male rat α2μ-globulin nephropathy. No treatment-related respiratory toxicity was noted in any species. This study did not demonstrate target-organ toxicity or carcinogenesis that could be extrapolated to other species.

Effects of ammonium dinitramide on preimplantation embryos in Sprague-Dawley rats.

Ammonium dinitramide (ADN) is a class 1.1 oxidizer that may be used in rocket propellants and explosives. Previous studies have shown that ADN is a female reproductive toxicant, causing implantation failure in Sprague–Dawley rats when it is administered during the preimplantation period of gestation. The purpose of this follow-up study was to identify the mechanism(s) associated with implantation failure following exposure to ADN. Mated female rats were treated with 2.0 grams per liter (g l-1) ADN in their drinking water for 24, 48, 72, or 96 h before preimplantation embryos were harvested from the oviducts or uterine horns. On gestation day 1 (GD-1), comparable numbers of morphologically normal two-cell embryos were harvested from the oviducts of the treatment and control groups. On GD-2, the development of the embryos harvested from the treated animals was either slowed or halted when compared to the control embryos. By GD-4, 98% of the embryos harvested from the control group had developed to the morula or blastocyst stage; these were collected from the uterine horns. On GD-4 in the treated group, 41% of the harvested embryos remained at the two- to six-cell stage and 59% were degenerate; 82% of these embryos were collected from the oviducts. These data suggest that the implantation failure seen in animals treated with ADN is due to embryolethality.

Dose- (and Time-) Dependent Blockade of Pregnancy in Sprague-Dawley Rats Administered Ammonium Dinitramide in Drinking Water

Ammonium dinitramide (ADN) is a class 1.1 explosive oxidizer that can be used in solid rocket propellant mixtures and explosives. A 90-day general toxicity/ reproductive screen performed on this compound at doses of 162, 103, 29, and 0.0 mg ADNlkglday resulted in a treatment-related adverse effect on litter production. Incidences of animals producing litters (1/11, 3/12, 12/12, and 11/12, respectively) and mean numbers of pups per litter (7, 7, 16, and 15, respectively) both were statistically significantly less than controls. In a follow- up study, mated dams treated with ADN at the same doses and examined at gestation days (GDs) 10 and 20 showed an effect in fetus loss similar to that seen in the reproductive screen. A pre- versus postimplantation dosing regimen indicated that implantation is vulnerable to ADN effects during the preimplantation period (GDs 1-3). No implantation sites were found in the rats treated with 2000 mg ADN/L drinking water (target dose of 160 mg ADNlkglday) during GDs 1-3. Numbers of implantation sites found in the rats treated during GDs 4-8 were similar to those found in the control group. The pituitary was not identified specifically in this study as the site of primary action, but serum progesterone was reduced by 27%, which may have resulted in reduced fertility.

Repeated-Dose Gavage Studies on Polychlorotrifluoroethylene Acids

C8 polychlorotrifluoroethylene (pCTFE) oligomers accumulate preferentially in the liver during long-term oral exposure and appear to be more hepatotoxic than C6 oligomers. A repeated-dose gavage study was initiated to determine the relative contributions of the corresponding C6 (trimer) and C8 (tetramer) acid metabolites to the toxicity of pCTFE in the male Fischer 344 rat. Test animals were dosed once per week for various time periods up to one year. A depression (p < 0.05) in mean body weight occurred in the highest dose tetramer acid (2.16 mg/kg) group. An increase in hepatic peroxisomal β-oxidation activity was found in the 2.16 mg pCTFE tetramer acid/kg dose group at the 3-, 6-, and 9-month sacrifice periods. An increase in relative liver weight was seen at all sacrifice periods in this dose group. Hepatocellular cytomegaly was a common finding in the higher dose tetramer acid groups but not in the trimer-treated rat groups.

The Determination of the Repeated Oral Toxicity of Halocarbon Oil, Series 27-S

Halocarbon 27-S (HC 27-S), a polymer of chlorotrifluoroethylene (CTFE), is used as a lubricating oil for pumps in hyperbaric chambers. Although monomeric CTFE has been shown to produce renal lesions in rats, the toxicity of CTFE polymers have not been investigated. To assess the toxicity of repeated exposure to HC 27–S, three groups (N = 6/group) of male and female Fischer-344 rats were dosed with 2.5 g HC 27-S/kg for 7 or 21 consecutive days. Groups were sacrificed at 7, 21, and 35 days (14 days after the 21-day dosing). Corresponding control groups (N = 6) were dosed with deionized water. Decreased water consumption and urine output were apparent in all test groups. Statistically significant increases in fluoride excretion were noted in 24-hr urine samples assessed periodically during the study. Neurotoxic signs were observed in female rats but not in male rats. Significant increases in liver and kidney weights were seen in all rats, regardless of number of dosing days. The increased fluoride burden in treated animals appeared sufficient to alter bone calcium/phosphate ratios in male rats but not female rats. Gross liver enlargement and hepatocellular cytomegaly indicated that the liver was probably the primary target organ following repeated administration of HC 27-S. (Supported by US Navy through Air Force Contract # F33615-085-C-0532.)