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Toxicological information

Carcinogenicity

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Administrative data

Endpoint:
carcinogenicity: oral
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study meets generally accepted scientific principles For read-across justification refer to section 13.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1977

Materials and methods

Principles of method if other than guideline:
A bioassay for possible carcinogenicity was conducted by administering the test material in feed to B6C3F1 mice. The chemical was administered to 50 males and 50 females at low and high concentrations, for 103 weeks. Matched-control groups were composed of 20 males and 20 females. Animals were analysed for mortality, clinical signs, histopathological as well as gross pathological changes.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
mouse
Strain:
B6C3F1
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, USA
- Weight at study initiation: 19-22 g
- Age at study initiation: 28 days
- Housing: five per cage in solid polycarbonate cages
- Diet: prepared from Wayne Lab Blox Meal (Allied Mills, Inc.) ad libitum
- Water: acidulated water ad libitum
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-25°C
- Humidity (%): 45-55%
- Air changes (per hr): 15 times per hour
- Photoperiod (hrs dark / hrs light): 16/8

Administration / exposure

Route of administration:
oral: feed
Details on exposure:
DIET PREPARATION
- Rate of preparation of diet (frequency): 2 times/week
- Mixing appropriate amounts with (Type of food): Wayne Lab Blox Meal (Allied Mills, Inc.)
- Storage temperature of food: 4°C
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
- Analyses were performed, using FDA methods to determine the efficiency of the mixing procedure and the stability of the test chemical in feed. Recoveries were found to be 90.3 + / -1.4% of the theoretical value at 7,500 ppm EDTA and 90.4 + / - 3.4% of the theoretical value at 3,750 ppm. It was concluded from these results that the preparations contained reasonably accurate concentrations of EDTA and were mixed homogeneously, and that the chemical was stable in feed for at least a week.
Duration of treatment / exposure:
103 weeks
Frequency of treatment:
daily
Doses / concentrations
Remarks:
Doses / Concentrations:
469, 938 mg/kg bw/day (original data: 3,750 ppm 7,500 ppm; conversion factor according to EU risk assessment)
Basis:
nominal in diet
No. of animals per sex per dose:
50 (except for the control, which consisted of only 20 animals)
Control animals:
yes, plain diet

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: twice daily

BODY WEIGHT: Yes
- Time schedule for examinations: approximately once a month



Sacrifice and pathology:
GROSS PATHOLOGY: Yes; all major organs, not specified but presumably all organs used for histopathology: skin, lymph nodes, mammary gland, salivary gland, bone marrow, trachea, lungs and bronchi, heart, thyroids, parathyroids, esophagus, stomach, small intestine, large intestine, liver, gallbladder, pancreas, spleen, kidneys, adrenals, urinary bladder, prostate or uterus, testis or ovary, brain, and pituitary.
HISTOPATHOLOGY: Yes;
skin, lymph nodes, mammary gland, salivary gland, bone marrow, trachea, lungs and bronchi, heart, thyroids, parathyroids, esophagus, stomach, small intestine, large intestine, liver, gallbladder, pancreas, spleen, kidneys, adrenals, urinary bladder, prostate or uterus, testis or ovary, brain, and pituitary.
Statistics:
- Statistical tests of differences in survival between groups are compared using the method of Cox (1972) for two groups and an extension of this method by Tarone (1975) for more than two groups.
- Statistical analysis of the incidence of tumors was made using the Fisher exact test (Cox, 1970) to compare a control group to a group of treated animals at each dose. In addition, the Armitage and Cochran test for linear trend in proportions, with continuity correction (Armitage, 1971), was used.

Results and discussion

Results of examinations

Histopathological findings: neoplastic:
effects observed, treatment-related
Details on results:
MORTALITY
No statistically significant difference in survival between the different groups in both sexes. (males: 5/50 (10%) of the low-dose group, 2/50 (4%) of the high-dose group, and 1/20 (5%) of the control; females: 0/50 low-dose female mice, 1/20 (5%) of the control group and 3/50 (6%) of the high-dose group)

CLINICAL SIGNS
Ataxia occurred in a low-dose male at 8 months, and ascites was noted in mice of both sexes during the second year of the study.

BODY WEIGHT AND WEIGHT GAIN
In male mice only the high-dose group showed throughout most of the test period a decrease in average body weight compared to the controls. In female mice average body weights of the treatment groups were depressed in a dose-related manner during the test period, although the effect was small. No individual data given. No information whether this effect is statistically relevant is available.

GROSS PATHOLOGY
Nothing reported.

HISTOPATHOLOGY: NEOPLASTIC
A variety of neoplasms were found in both treated and control animals that were well known from historical controls of the same strain. There was a high incidence of tumors in the hematopoictic, endocrine, digestive, and respiratory systems. The incidence of neoplasms in other systems was variable. For all tumor types observed no statistical significance were seen between incidences in dose groups and control groups (see table 1 and 2).

Effect levels

open allclose all
Dose descriptor:
NOAEL
Effect level:
938 mg/kg bw/day (nominal)
Sex:
male/female
Remarks on result:
other: Effect type: carcinogenicity (migrated information)
Dose descriptor:
NOAEL
Effect level:
938 mg/kg bw/day (nominal)
Sex:
male/female
Remarks on result:
other: Effect type: toxicity (migrated information)

Any other information on results incl. tables

Table 1: Analyses of the Incidence of Primary Tumors at Specific Sites in Male Mice Fed EDTA Trisodium Salt in the Diet

Morphology (p-value) Control 469 mg/kg bw/day 938 mg/kg bw/day
Hematopoietic System:  Malignant Lymphoma  2/20 (n.s.) 7/46 (n.s.) 7/48 (n.s.)
Weeks to first observed tumor: 91 73 87
Thyroid: C-cell Adenoma 0/10 (n.s.) 1/29 (n.s.) 1/33 (n.s.)
Weeks to first observed tumor: - 104 105
Pituitary: Chromophobe Adenoma 1/13 (n.s.) 0/19 (n.s.) 1/26 (n.s.)
Weeks to first observed tumor: 105 - 105
Lung: Alveolar/Bronchiolar Adenoma and Carcinoma 2/18 (0.096) 8/44 (n.s.) 12/45 (n.s.)
Weeks to first observed tumor: 105 99 96
Liver: Hepatocellular Adenoma and Neoplastic Nodule 3/19 (n.s.) 10/44 (n.s.) 10/47 (n.s.)
Weeks to first observed tumor: 103 84 105

Table 2: Analyses of the Incidence of Primary Tumors at Specific Sites in Female Mice Fed EDTA Trisodium Salt in the Diet

Morphology (p-value) Control 625 mg/kg bw/day 1250 mg/kg bw/day
Hematopoietic System:  Malignant Lymphoma  5/19 (n.s.) 11/49 (n.s.) 12/47 (n.s.)
Weeks to first observed tumor: 85 99 93
Thyroid: C-cell Adenoma 1/12 (n.s.) 3/33 (n.s.) 1/34 (n.s.)
Weeks to first observed tumor: 105 99 105
Pituitary: Chromophobe Adenoma 2/12 (n.s.) 6/34 (n.s.) 4/29 (n.s.)
Weeks to first observed tumor: 105 105 105
Lung: Alveolar/Bronchiolar Adenoma and Carcinoma 0/19 (n.s.) 3/47 (n.s.) 3/49 (n.s.)
Weeks to first observed tumor: - 105 102
Liver: Hepatocellular Adenoma and Neoplastic Nodule 0/19 (n.s.) 1/46 (n.s.) 1/47 (n.s.)
Weeks to first observed tumor: - 99 105

n.s. = not significant

Applicant's summary and conclusion