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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1996
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study
Cross-reference
Reason / purpose:
reference to same study

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1996
Report Date:
1996
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999
Reference Type:
other: abstract
Title:
No information
Author:
Wahle, B.S. et al.
Year:
1997
Bibliographic source:
The Toxicologist, 36, Part 2, Abstr. 1733
Reference Type:
secondary source
Title:
O-Phenylphenol and its Sodium and Potassium Salts: A Toxicological Assessment
Author:
Bomhard, E. M. et al.
Year:
2002
Bibliographic source:
Crit. Rev. Toxicol. 32(6):551-626

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)
Deviations:
yes
Remarks:
animals were > 6 weeks of age when dosing commenced and the lowest dose is < 10% of highest dose for females
Qualifier:
according to
Guideline:
other: US-EPA FIFRA Guideline 83-5
Qualifier:
according to
Guideline:
other: EPA OTS 798.3320 (Combined Chronic Toxicity/Oncogenicity Studies)
Qualifier:
according to
Guideline:
other: MAFF Guideline 59 NohSan No. 4200 Combined Chronic Toxicity/Oncogenicity Studies
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): ortho-phenylphenol (OPP)
- Analytical purity: 99.7, 99.9, 100.0, and 99.5%
- Purity test date: Mar 1993, Nov 1993, Aug 1994, Sep 1995
- Lot/batch No.: S-01-93
- Stability: proven by purity analysis
- Storage condition of test material: under freezer conditions (approximately -23°C)

Test animals

Species:
rat
Strain:
other: CDF[F344]/BR
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: SASCO, Inc., MAdison, WI
- Age at study initiation: approximately 8 weeks
- Fasting period before study: no
- Housing: individually in suspended stainless stell wire-mesh cages; each cage containing a feeder, a pressure-activated water nipple, and deotised cage board in the bedding tray
- Diet: Purina Mills Rodent Lab Chow 5001-4 in "etts" form, ad libitum
- Water: tap water (municipal water supply of Kansas City, MO
- Acclimation period: at least 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-26
- Humidity (%): 40-70
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: feed
Vehicle:
other: Acetone/corn oil mixture
Details on oral exposure:
DIET PREPARATION
- Rate of preparation of diet (frequency): weekly

VEHICLE
- Justification for use and choice of vehicle (if other than water): solubility properties of the test item
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
9 Analysis of the test substance in various test diets during the in-life phase of the study revealed mean analytical concentrations of 732 ppm (CV=6%), 3730 ppm (CV=8%), 7385 ppm (CV=8%), and 9510 ppm (CV=6%), with all values remaining within 10% of the corresponding nominam concentrations of 800, 4000, 8000, and 10,000 ppm, respectively.
The test substance was further shown to be stable following both room temperature and freezer storage over a period of 14 and 28 days and homogeneously distributed in the feed over a concentration range of 800-10,000 ppm.
Duration of treatment / exposure:
2 years
Frequency of treatment:
daily
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
800, 4000, and 8000 (males) or 10,000 (females) ppm
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
39±1, 200±3, and 402±6 mg/kg bw/day (males)
Basis:
other: mean daily intake calculated from feed consumption, body weight, and diet analysis data
Remarks:
Doses / Concentrations:
49±0, 248±3, and 647±6 mg/kg bw/day (females)
Basis:
other: mean daily intake calculated from feed consumption, body weight, and diet analysis data
No. of animals per sex per dose:
- control group: a total of 70 males + 70 females, 20 per sex served for interim sacrifice after 1 year, 50 per sex were kept and sacrificed after 2 years
- 800 ppm: a total of 60 males + 60 females, 10 per sex served for interim sacrifice after 1 year, 50 per sex were kept and sacrificed after 2 years
- 4000 ppm: a total of 60 males + 60 females, 10 per sex served for interim sacrifice after 1 year, 50 per sex were kept and sacrificed after 2 years
- 8000 ppm: a total of 70 males, 20 served for interim sacrifice after 1 year, 50 per sex were kept and sacrificed after 2 years
- 10,000 ppm: a total of 70 females, 20 served for interim sacrifice after 1 year, 50 per sex were kept and sacrificed after 2 years
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: based on literature review and a 4-week range finding study in the rat

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily (once on the weekends and holidays)
- Cage side observations included: moribundity and mortality, evaluation of external surface areas, orifices, posture, general behaviour, respiration, and excretory products

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: pre-exposure and at sacrifice
- Dose groups that were examined: all animals

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at 3, 6, 12, 18, and 24 months
- Anaesthetic used for blood collection: No data
- Animals fasted: Yes (overnight)
- How many animals: 20 rats/sex/dose (the same animals were used for urinalysis)
- Parameters checked: platelet count, leukocyte count, erythrocyte count, Hb, haematocrit, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), methaemoglobin (Met-Hb), leukocyte differential, (atypical lymphocytes, band neutrophils, basophils, blasts, hematrak comments, eosinophils, lymphocytes, metamyelocytes, monocytes, myelocytes, nucleated red blood cells (RBC), plasma cells, promyelocytes, segmented neutrophils), erythrocyte morphology (anisocytosis, basophilic stippling, hypersegmented neutrophils, hypochromasia, macrocytosis, microcytosis, poikilocytosis, polychromasia, spherocytosis, target cells, toxic granulation), special stains (reticulocyte count, heinz bodies)

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at 3, 6, 12, 18, and 24 months
- Animals fasted: Yes (overnight)
- How many animals: 20 rats/sex/dose (the same animals were used for urinalysis)
- Parameters checked: Na, K, Cl, P, Ca, urea nitrogen, glucose, creatinine, uric acid, triglyceride, cholesterol, creatine kinase, lactate dehydrogenase (LDH), aspartate transaminase (AST), alanine transaminase (ALT), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (AP), total bilirubin, direct bilirubin, total protein, albumin, globulin

URINALYSIS: Yes
- Time schedule for collection of urine: at 3, 6, 12, 18, and 24 months (the week prior to the week of blood collection)
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes (overnight)
- How many animals: 20 rats/sex/dose (the same animals were used for blood collection)
- Parameters checked: appearance, clarity, colour, specific gravity, pH, protein, glucose, ketones, bilirubin, blood, urobilinogen, nitrite, microscopic evaluation of solids
Sacrifice and pathology:
GROSS PATHOLOGY: Yes
ORGAN WEIGHTS: Yes (adrenals, brain, heart, kidneys, liver, lungs, ovaries, spleen, testicles, thyroid)
HISTOPATHOLOGY: Yes (adrenals, aorta, bone (femur, Rib/cc jct, sternum), bone marrow, brain (cerebellum, cerebrum-midbrain, medulla/pons), caecum, cervix, clitoral gland, colon, epididymidis, oesophagus, exorbital(lacrimal gland, eyes, gross lesions, harderian gland, heart, joint fem/tib, kidneys, larynx, liver, lungs, lymph nodes (cervical and mesenteric), mammary gland, muscle, nerve (optic and sciatic), ovaries, pancreas, parathyroid, physical identifier, pituitary, prepupital gland, prostate, rectum, salivary gland, seminal vesicles, skin, skull, small intestine (duodenum, ileum, jejunum), spinal cord (cervical, lumbar, thoracic), spleen, stomach, testicles, thymus, thyroid, trachea, ureters, urinary bladder, uterus, vagina)
Statistics:
Continous data were evaluated initially for equality or homogeneity of variance using Bartlett's test. Group means were further analysed by a one-way variance analysis (ANOVA) followed by Dunnett's test. In the event of unequal variances, and at the discretion of the study director, data were subject to non-parametric procedures consisting of a Kruskal-Wallis ANOVA followed by the Mann-Whitney-U test for between-group comparisons. Frequency data were initially examined for trends, data suggestive of a potential effect were then statistically evaluated using the chi-square, Fisher-exact, or chi-square and Fisher-exact tests. On a case by case basis, and at the discretion of the study director, data were subject to additional statistical procedures other than mentioned above. For the Bartlett test, a probability (p) value of ≤0.01 was considered significant; for all other tests, differences with p values ≤0.05 were considered statistically significant.

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Description (incidence and severity):
Changes noted are toxicologically not relevant.
Mortality:
no mortality observed
Description (incidence):
Changes noted are toxicologically not relevant.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
4000 ppm males/females: 5% decrased body weight gain; 8000 ppm males and 10,000 ppm females: 11% decrased body weight gain
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
no effects observed
Haematological findings:
no effects observed
Description (incidence and severity):
Changes noted are toxicologically not relevant.
Clinical biochemistry findings:
no effects observed
Description (incidence and severity):
Changes noted are toxicologically not relevant.
Urinalysis findings:
effects observed, treatment-related
Description (incidence and severity):
8000 ppm males: increased incidence of blood in urine
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
4000 ppm males: urinary bladder masses; 8000 ppm males: increased incidence of ventrum wet/stained and urinary bladder masses; 10,000 ppm females: increased incidence of ventrum wet/stained and pitted zones and abnormal texture in kidney
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
8000 ppm males: urinary bladder calculi, congestions, haemorrhage, mineralization, necrosis, calculi in renal pelvis, renal cystic tubular dilatation; 10,000 ppm females: renal mineralisation, renal cystic tubular dilatation, renal infarct
Histopathological findings: neoplastic:
effects observed, treatment-related
Description (incidence and severity):
8000 ppm males: simple urinary bladder hyperplasia, transitional cell carcinoma; 10,000 ppm females: simple urinary bladder hyperplasia, ureter dilatation and/or transitional cell hyperplasia, renal tubular hyperplasia
Details on results:
CLINICAL SIGNS AND MORTALITY
A slight increase in mortality was suggested for high dose males (8000 ppm), based on an increased number of unscheduled kills and a corresponding decrease in mean time of death (days). In contrast, a slight increase in mean time of death was observed for high dose females (10,000 ppm). Number of animals found dead on study was comparable between treated and control animals of each sex.
Test material related cage side observations were generally noted in mid and high dose animals (4000 and 8000/10,000 ppm) and included a statistically increased frequency of abnormal colour urination, urine stains, and red and/or brown stains primarily located in the perigenital area. While many interpretations regarding these observations may be plausible, the true toxicological significance, if any, remains unclear.

BODY WEIGHT AND WEIGHT GAIN
There was no test material-related effect noted in the low dose group (800 ppm) animals (both males and females). A decreased body weight of 5% was noted in both males and females treated with 4000 ppm and a decline of 11% was noted in high dose males (8000 ppm) and females (10,000 ppm).

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
There was no test material-related effect noted in any of the dose groups. Compound intake was calculated from feed consumption, body weight, and diet analysis data and amounted 39±1, 200±3, and 402±6 mg/kg bw/day for males and 49±0, 248±3, and 647±6 mg/kg bw/day for females, respectively.

OPHTHALMOSCOPIC EXAMINATION
There was no test material-related effect noted in any of the dose groups.

HAEMATOLOGY
There was no test material-related effect noted in low and mid dose animals (800 and 4000 ppm) and in high dose males (8000 ppm). Decreases in haemoglobin concentration, haematocrit, MCV and MCHC were suggested in high dose females (10,000 ppm); however, these changes were within the historical control range, did not persist over time intervals, and were therefore considered equivocal.

CLINICAL CHEMISTRY
There was no test material-related effect noted in any of the dose groups.

URINALYSIS
The only urinary consideration following exposure to OPP was increased incidence of blood in the urine of high dose males (8000 ppm). This finding is associated with the bladder neoplasia noted in high dose males.

ORGAN WEIGHTS
There was no test material-related effect noted in any of the dose groups.

GROSS PATHOLOGY
An increased incidence of urinary bladder masses was suggested for high dose males (8000 ppm) at both 1-year and 2-year sacrifices and for mid dose males (4000 ppm) at the 2-year sacrifice. This observation is likely associated with morphologic changes noted microscopically in the bladder.
An increase in the incidence of wet ventrum was noted in high dose females (10,000 ppm) at the interim sacrifice after 1 year of exposure. A similar increase in wet ventrum with staining was observed at terminal sacrifice in high dose males (8000 ppm) and females (10,000 ppm), and was simply a reiteration of the urine and the red staining of the perigenital area seen during the in-life portion of the study.
In the kidney, an increased incidence of pitted zones and abnormal texture was noted in highdose females (10,000 ppm) at terminal sacrifice.

HISTOPATHOLOGY: NON-NEOPLASTIC
Urinary bladder calculi, congestions, haemorrhage, mineralization and necrosis were noted in high dose males (8000 ppm) at terminal sacrifice after 2 years. At the interim sacrifice, high dose males showed further calculi in the renal pelvis and at terminal sacrifice renal cystic tubular dilatation was noted.
In high dose females (10,000 ppm), renal mineralisation were noted at terminal sacrifice after 2 years of exposure. Renal cystic tubular dilatation and renal infarct (wedge-shaped lesions without vascular involvement were noted in animals of the same group at both interim and terminal sacrifice.

HISTOPATHOLOGY: NEOPLASTIC (if applicable)
In high dose males (8000 ppm), simple urinary bladder hyperplasia and transitional cell carcinoma were noted at both 1- and 2-year sacrifices.
In high dose females (10,000 ppm), simple urinary bladder hyperplasia, ureter dilatation and/or transitional cell hyperplasia and renal tubular hyperplasia were noted at terminal sacrifice after 2 years of exposure.

Effect levels

open allclose all
Dose descriptor:
NOAEL
Remarks:
sytemic toxicity
Effect level:
39 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Basis for effect level:
other: corresponding to 800 ppm
Dose descriptor:
LOAEL
Remarks:
sytemic toxicity
Effect level:
200 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Basis for effect level:
other: corresponding to 4000 ppm; based on structural alterations in the urinary bladder
Dose descriptor:
NOAEL
Remarks:
sytemic toxicity
Effect level:
248 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Basis for effect level:
other: corresponding to 4000 ppm
Dose descriptor:
LOAEL
Remarks:
sytemic toxicity
Effect level:
647 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Basis for effect level:
other: corresponding to 10,000 ppm; based on renal mineralisation, renal cystic tubular dilatation, renal infarct

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

The toxicological response to the 2 year daily intake of OPP can mainly characterized as structural alterations in the urinary bladder and kidney. But there was no compound-related change in various parameters associated with these organs at doses at 800 and 4000 ppm in both sexes. Body weight declined slightly at doses of 4000 ppm or above. Food consumption, ophthalmology, organ weights as well as haematological and clinical chemistry values remained unaffected. Urine analysis gave an increased incidence of blood in the urine of the 8000 ppm males only. Carcinogenicity: The urinary bladder showed evidence of a compound-induced neoplasia in both 4000- and 8000 ppm male rats only. While this effect was unequivocal at 8000 ppm, it was considered border-line at 4000 ppm as there was only a marginal and non-statistical increase in both urinary bladder hyperplasia and transitional cell carcinoma when compared to controls or 800 ppm males. Evidence of a compound-induced neoplasia was not observed in female animals at any dose tested.

NOAEL systemic, males: 800 ppm (39 mg/kg bw/day)

LOAEL systemic, males: 4000 ppm (200 mg/kg bw/day), based on structural alterations in the urinary bladder

NOAEL systemic, females: 4000 ppm (248 mg/kg bw/day)

LOAEL systemic, females: 10,000 ppm (647 mg/kg bw/day), based on renal mineralisation, renal cystic tubular dilatation, renal infarct

NOAEL carcinogenicity: 4000 ppm (200 mg/kg bw/day)

LOAEL carcinogenicity: 8000 ppm (402 mg/kg bw/day), based on neoplasms (malignant and benign) in the urinary bladder

NOAEL carcinogenicity, females: ≥10,000 ppm (647 mg/kg bw/day)

Applicant's summary and conclusion