With regard to repeated dose toxicity, no animals died in any groups. Decrease in locomotor activity and suppression of body weight gain were observed in males of the groups receiving 300 mg/kg/day or more. Decreases in locomotor activity, body weight gain and food consumption were observed in females of the 1000 mg/kg/day group. Increase in relative kidney weights was observed in males of the 300 and 1000 mg/kg/day groups and in females of the 1000 mg/kg/day group. Centrilobular hypertrophy of hepatocytes was observed in males and females of the 300 and 1000 mg/kg/day groups, along with a ground glass appearance of the cells in the males.
NOELs for toxicity of 2,6-dichlorotoluene are considered to be 300 mg/kg/day in males and 100 mg/kg/day in females.
Regarding reproductive/developmental toxicity, no adverse effects on copulation, fertility and delivery were noted in any groups. Numbers of dead pups were increased and viability on postnatal day 4 was decreased in the 300 and 1000 mg/kg/day groups. Pup weights on postnatal day 4 showed a tendency for decrease in the 1000 mg/kg group. No morphological abnormalities were found in pups of any of the 2,6-dichlorotoluene -treated groups.
The NOELs for reproductive/developmental toxicity are considered to be 1000 mg/kg/day in males, 100 mg/kg/day in females, and 300 mg/kg/day in offspring.
Genotoxicity of 2,6-dichlorotoluene was studied in a reverse mutation test in bacteria. This substance was not mutagenic in Salmonella typhimurium TA100, TA1535, TA98, TA1537 or Escherichia coli WP2 uvrA, with or without an exogenous metabolic activation system.
Genotoxicity of 2,6-dichlorotoluene was studied by a chromosomal aberration test in cultured Chinese hamster lung (CHL/IU) cells.
2,6-Dichlorotoluene did not induce either structural chromosomal aberrations or polyploidy at any dose, with or without a metabolic activation system.
| Purity | : | 99.2 % |
| Test species/strain | : | Rat/Crj:CD |
| Test method | : | OECD Test Guideline 422 |
| Route | : | Oral (gavage) |
| Doses | : | 0 (vehicle), 30, 100, 300, 1000 mg/kg/day |
| Number of animals/group | : | Males, 13; females, 13 |
| Vehicle | : | Corn oil |
| Administration period | : | Males, 42 days Females, from 14 days prior to mating to day 3 of lactation |
| Terminal killing | : | Males, day 43 Females, day 4 of lactation |
| GLP | : | Yes |
Test results:
1. Males: Decrease in locomotor activity was observed in one animal in the 300 mg/kg group, as well as decrease in locomotor activity (9 animals) and adoption of a prone position (2 animals) in the 1000 mg/kg group. Body weight gain was suppressed in the 300 and 1000 mg/kg groups. Autopsy following treatment for 42 days demonstrated increases in the relative kidney weights in the 300 and 1000 mg/kg groups and the relative liver weights in the 1000 mg/kg group. As histopathological findings, increase in eosinophilic bodies in the kidneys was observed in the groups receiving 100 mg/kg or more, and centrilobular hypertrophy and ground glass appearance of the hepatocytes were observed in those with 300 mg/kg and more. Decrease in the concentration of glucose was determined in the 300 and 1000 mg/kg groups. No effects of 2,6-dichlorotoluene were observed on food consumption and hematology.
2. Females: Decrease in locomotor activity (all animals tested), adoption of a prone position (10 animals) and incomplete eyelid opening (6 animals) were observed in the 1000 mg/kg group. Food consumption was decreased as well as suppression of body weight gain in the 1000 mg/kg group. At autopsy on postpartum day 4, increases in the relative kidney weight and relative liver weight were found in the 1000 mg/kg group. As histopathological findings, vacuolar and fatty degeneration in the proximal kidney tubules and centrilobular hypertrophy of the hepatocytes were observed in the 300 and 1000 mg/kg groups. In addition, decreases in the relative thymus weight and atrophy of the thymus were observed in the 300 mg/kg and more groups. No effects of 2,6-dichlorotoluene were observed on urinalysis.
NOELs for repeated dose toxicity of 2,6-dichlorotoluene are considered to be 30 mg/kg/day in males and 100 mg/kg/day in females.
<Reproductive and developmental toxicity>
No adverse effects of 2,6-dichlorotoluene at any dose level were noted for copulation, fertility or delivery. Numbers of dead pups were increased and viability on postnatal day 4 was decreased in the 300 and 1000 mg/kg groups. Pup weights on postnatal day 4 tended to be decreased in the 1000 mg/kg group. No morphological abnormalities were found in pups of any 2,6-dichlorotoluene -treated group.
NOELs for reproductive and developmental toxicity of 2,6-dichlorotoluene are considered to be 1000 mg/kg/day in males, 100 mg/kg/day in females and 300 mg/kg/day in offspring.
| Purity | : | 99.6 % |
| Test species/strains | : | Salmonella typhimurium TA100, TA1535, TA98, TA1537, Escherichia coli WP2 uvrA |
| Test method | : | Guidelines for Screening Mutagenicity Testing of Chemicals (Chemical Substances Control Law of Japan) and OECD Test Guideline 471 |
| Procedures | : | Plate incorporation method |
| Solvent | : | Dimethyl sulfoxide |
| Positive controls | : | -S9 mix; 2-(2-Furyl)-3-(5-nitro-2-furyl)acrylamide (TA100, TA98, WP2 uvrA), Sodium azide (TA1535) and 9-Aminoacridine (TA1537) +S9 mix; 2-Aminoanthracene (five strains) |
| Dosage | : | -S9 mix; 0, 4.69, 9.38, 18.8, 37.5, 75.0, 150 μg/plate (TA100, TA98, TA1537, WP2 uvrA) -S9 mix; 0, 2.34, 4.69, 9.38, 18.8, 37.5, 75.0, 150 μg/plate (TA1535) +S9 mix; 0, 18.8, 37.5, 75.0, 150, 300, 600 μg/plate (TA100, TA98, TA1537, WP2 uvrA) +S9 mix; 0, 9.38, 18.8, 37.5, 75.0, 150, 300, 600 μg/plate (TA1535) |
| S9 | : | Rat liver, induced with phenobarbital and 5,6-benzoflavone |
| Plates/test | : | 3 (1 for cytotoxicity test) |
| Number of replicates | : | 2 (plus 1 cytotoxicity test) |
| GLP | : | Yes |
Test results:
Genetic effects:
Salmonella typhimurium TA100, TA98, TA1535, TA1537
| + | ? | - | |
| Without metabolic activation: | [ ] | [ ] | [*] |
| With metabolic activation: | [ ] | [ ] | [*] |
Escherichia coli WP2 uvrA
| + | ? | - | |
| Without metabolic activation: | [ ] | [ ] | [*] |
| With metabolic activation: | [ ] | [ ] | [*] |
| Purity | : | 99.6 % |
| Type of cell used | : | Chinese hamster lung (CHL/IU) cells |
| Test method | : | Guidelines for Screening Mutagenicity Testing of Chemicals (Chemical Substances Control Law of Japan) and OECD Test Guideline 473 |
| Solvent | : | Dimethyl sulfoxide |
| Positive controls | : | -S9 mix; Mitomycin C +S9 mix; Cyclophosphamide |
| Dosage | : | -S9 mix (6 hr short-term treatment); 0, 0.008, 0.017 mg/mL +S9 mix (6 hr short-term treatment); 0, 0.024, 0.048 mg/mL -S9 mix (24 and 48 hrs continuous treatment); 0, 0.017, 0.035 mg/mL |
| S9 | : | Rat liver, induced with phenobarbital and 5, 6-benzoflavone |
| Plates/test | : | 2 |
| GLP | : | Yes |
Test results:
Genotoxic effects:
| clastogenicity | polyploidy | |||||
| + | ? | - | + | ? | - | |
| Without metabolic activation: | [ ] | [ ] | [*] | [ ] | [ ] | [*] |
| With metabolic activation: | [ ] | [ ] | [*] | [ ] | [ ] | [*] |
| 1) | The tests were performed by the Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano-shi, Kanagawa, 257-8523, Japan. Tel +81-463-82-4751 Fax +81-463-82-9627 |