Nonylphenol, branched, ethoxylated

Endpoint summary

Description of key information

The NOAEL of 40 mg/kg bw/d from a 2 year study in rat with NPE-4 was selected as representative for NPEO and carried forward for DNEL derivation.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

chronic toxicity: oral

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, few details but meets basic scientific principles.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Principles of method if other than guideline:

A chronic oral repeated dose study was conducted in rats at 0, 40, 200 and 1,000 mg/kg bw/d to evaluate the systemic effects of NPE-4 in rat. Parameters including bodyweight, food consumption, food utilization, mortality, abnormal behavior, clinical chemistry, haematology, gross and histopathological changes were observed at regular intervals.

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Housing: Housed individually in wire-bottom cages
- Diet (e.g. ad libitum): Rockland rat diet
- Water (e.g. ad libitum): Ad libitum

Route of administration:

oral: feed

Vehicle:

not specified

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): The concentration was adjusted from time to time to maintain the dosage constant

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No data

Duration of treatment / exposure:

2 years

Frequency of treatment:

Daily

Remarks:

Doses / Concentrations:
0 mg/kg bw/d (control)
Basis:
nominal in diet

Remarks:

Doses / Concentrations:
40 mg/kg bw/d
Basis:
nominal in diet

Remarks:

Doses / Concentrations:
200 mg/kg bw/d
Basis:
nominal in diet

Remarks:

Doses / Concentrations:
1000 mg/kg bw/d
Basis:
nominal in diet

No. of animals per sex per dose:

35 (plus 5 animals per sex in the highest and control dosage group)

Control animals:

yes, plain diet

Details on study design:

No data

Positive control:

No

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes

DETAILED CLINICAL OBSERVATIONS/MORTILITY: Yes
- Time schedule: No data

BODY WEIGHT: Yes
- Time schedule for examinations: Weekly for 13 wk and biweekly to 1 year, then monthly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes (for 12 wk and then irregularly thereafter)
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Before the first dose, and after 3, 6, 12, 18, and 24 months
- Anaesthetic used for blood collection: Yes (identity) / No / No data
- Animals fasted: No data
- How many animals: 5 of each sex on the highest dosage and the control diet
- Parameters checked in table [No.?] were examined: Haemoglobin, total red and white blood cell count and differential white cell count

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Before the first dose, and after 3, 6, 12, 18, and 24 months
- Animals fasted: No data
- How many animals: 5 of each sex on the highest dosage and the control diet
- Parameters examined: Urinary reducing substances, protein, and formed elements.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

OTHER: Animals were observed daily for abnormal behavior

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (including tumors)

After 12 months , 5 of each sex from the highest dosage and from the control groups and 3 of each sex from each of the two lower-dosage groups and after 24 months all were sacrificed

HISTOPATHOLOGY: Yes

- Histopathologic examination of 28 tissues was done on 5 rats of each sex on the highest dosage and in the control diet groups at each sacrifice.

Other examinations:

Organ weights of kidney, liver and testes were measured

Statistics:

Yes, but no details reported

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

BODY WEIGHT AND WEIGHT GAIN: At 1000 mg/kg/d both sexes, and at 200 mg/kg/d the females had gained less weight than the controls after 12 months, but did not differ from the controls after 24 months.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): The groups who gained less weight ate less than did the controls, and the growth effect was attributed to poor palatability of the diets.

ORGAN WEIGHTS: A slight elevation of liver weight in relation to body weight in both sexes on an intake of 1000 mg/kg/d was observed

GROSS PATHOLOGY

HISTOPATHOLOGY: Microscopically the livers were normal, hence the slight elevation of liver weight in relation to body weight observed, was not considered to be adverse

Dose descriptor:

NOAEL

Effect level:

40 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: overall effects

Critical effects observed:

not specified

None

Conclusions:

The NOAEL of NPE-4 can be considered to be 40 mg/kg bw/d based on no systemic effects observed at any of the tested the dosages in neither sexes.

Executive summary:

A chronic feeding study was conducted to evaluate the systemic toxicity of NPE-4 in rats. The test material was administered at 0, 40, 200 and 1,000 mg/kg bw/d to rats in the diet over a 2-year period. Each dosage group consisted of 35 male and 35 female rats, with 5 male and 5 female rats in addition in the highest and control dosage groups reserved for periodic clinical test. Food consumption was calculated weekly for 12 weeks, irregularly thereafter. The rats were weighed weekly for 13 weeks, biweekly to 1 year, then monthly. Food utilization was calculated for the first 12 weeks. Animals were observed daily for abnormal behavior. Before the first dose, and after 3, 6, 12, 18 and 24 months clinical tests were performed on the 5 of each sex at the highest dosage and the control diet. All rats dying or sacrificed were carefully examined for gross pathologic changes, including tumors. After 12 months 5 of each sex from the highest dosage and from the control group were sacrificed, 3 of each sex from each of the two lower-dosage groups. After 24 months, all rats were sacrificed and organs were weighed. Histopathologic examination of tissues was conducted on 5 rats of each sex at the highest dosage and in the control group at each sacrifice. All numerical results were evaluated by appropriate statistical tests. At 1,000 (both sexes) and 200 (females) mg/kg/ bw/day, animals gained less weight than the controls after 12 months, but did not differ from the controls after 24 months. The groups that gained less weight ate less than controls and the growth effect was attributed to poor palatability of the diets. A slight elevation of liver weight in relation to body weight in both sexes at 1,000 mg/kg bw/d was observed. Microscopically, the livers were normal, hence the slight elevation of liver weight in relation to body weight was not considered to be adverse. Based on the above results, the NOAEL of NPE-4 can be considered to be 40 mg/kg bw/d based on no systemic effects observed at the lowest dosage in either sex (Smyth HF et al.,1969).

Endpoint conclusion

Dose descriptor:

NOAEL

40 mg/kg bw/day

Study duration:

chronic

Species:

rat

Additional information

Oral

No repeated dose toxicity studies are available directly on NPEO. However, a significant amount of data exists for NPE-4 and NP. The ADME information on nonyl phenol ethoxylates indicates that they are not significantly metabolized down to free NP (Section 5.1.1). The repeated dose toxicity of NPEO is therefore expected to be more similar to that of NPE-4, although NOAELs for NPE-4 and NP are very similar (40 and 50 mg/kg/d, respectively).

NPE-4

A 90 day feeding study was conducted to evaluate the systemic effects of NPE-4 in rat. Doses of 0, 40, 200 and 1,000 mg/kg bw/d of the test material were administered to 10 male and 10 female Sprague-Dawley weanling albino rats for 90 days. The animals were weighed weekly and their condition and behavior were noted. Hematology was studied and the urine examined in pooled samples. Evaluations were made for gross pathology and organ weight. Tissues were examined histopathologically. Effects were observed on growth rate, but these were shown to be due to poor palatability of the diets. Absolute and relative liver weights of both sexes were higher than those of control rats at 1,000 and 200 mg/bw kg/d, respectively. No histopathological changes were found in liver sections. The increased liver weight was interpreted as an increase in parenchymatous tissue resulting from increased enzyme activity in metabolizing the materials fed. Based on the above results, the NOAEL of NPE-4 can be considered to be 40 mg/kg bw/d based on no systemic effects observed at the lowest dosage in both sexes (Smyth HF et al.,1969).

A 90 day feeding study was conducted to evaluate the systemic toxicity of NPE-4 in dogs. Doses of 0, 40, 200 and 1,000 mg/kg bw/d were administered to groups of 2 male and 2 female purebred Beagle dogs in good condition, via gelatin capsules 7 days a week following dry diet mixed with water. Animal behavior was observed daily, weights were recorded weekly. Before the first dose and after 80 doses, clinical tests were performed. Gross pathology was conducted. Organs were weighed and histopathologic examination of tissues was performed. No systemic effects were observed at the lowest dose in either sex. Thus the NOAEL of NPE-4 in this study can be considered to be 40 mg/kg bw/d (Smyth HF et al.,1969).

A chronic feeding study was conducted to evaluate the systemic toxicity of NPE-4 in rats. The test material was administered at 0, 40, 200 and 1,000 mg/kg bw/d to rats in the diet over a 2-year period. Each dosage group consisted of 35 male and 35 female rats, with 5 male and 5 female rats in addition in the highest and control dosage groups reserved for periodic clinical test. Food consumption was calculated weekly for 12 weeks, irregularly thereafter. The rats were weighed weekly for 13 weeks, biweekly to 1 year, then monthly. Food utilization was calculated for the first 12 weeks. Animals were observed daily for abnormal behavior. Before the first dose, and after 3, 6, 12, 18 and 24 months clinical tests were performed on the 5 of each sex at the highest dosage and the control diet. All rats dying or sacrificed were carefully examined for gross pathologic changes, including tumors. After 12 months 5 of each sex from the highest dosage and from the control group were sacrificed, 3 of each sex from each of the two lower-dosage groups. After 24 months, all rats were sacrificed and organs were weighed. Histopathologic examination of tissues was conducted on 5 rats of each sex at the highest dosage and in the control group at each sacrifice. All numerical results were evaluated by appropriate statistical tests. At 1,000 (both sexes) and 200 (females) mg/kg/ bw/day, animals gained less weight than the controls after 12 months, but did not differ from the controls after 24 months. The groups that gained less weight ate less than controls and the growth effect was attributed to poor palatability of the diets. A slight elevation of liver weight in relation to body weight in both sexes at 1,000 mg/kg bw/d was observed. Microscopically, the livers were normal, hence the slight elevation of liver weight in relation to body weight was not considered to be adverse. Based on the above results, the NOAEL of NPE-4 can be considered to be 40 mg/kg bw/d based on no systemic effects observed at the lowest dosage in either sex (Smyth HF et al.,1969).

A chronic feeding study was conducted to evaluate the systemic toxicity of NPE-4 in dogs. The test material at 0, 40, 200 and 1,000 mg/kg bw/d was administrated to dogs over a 2-year period. Each dose was given to 3 Beagle hounds of each sex. Immediately after the feeding period, uneaten diet was removed and gelatin capsules were given containing different dosages of NPE-4, with an untreated control group. The dogs were weighed weekly and observed daily for signs of effect. Before the study started and after 90, 180, 360, 540 and 720 days, clinical tests were performed on all dogs. After 720 days, fasting blood glucose levels were determined. All dogs were sacrificed and carefully examined grossly. Tissues were examined microscopically. During the first week of feeding, occasional emesis was seen at all dose levels, but thereafter it occurred infrequently and only in the high dose group (1,000 mg/kg bw/d). At 1,000 mg/kg bw/d, body weight was reduced. Each time this occurred, the high protein portion of the diet was increased until anorexia was corrected and body weight was regained. At 1,000 mg/kg bw/d food intake was reduced. At 1,000 mg/kg bw/d, there was a moderate elevation in serum alkaline phosphatase. This effect was also seen in the 200 mg/kg bw/d group, but to a lesser degree. At 1,000 mg/kg bw/d there was a moderate elevation in liver to body weight ratio. This effect was also seen in the 200 mg/kg bw/d group, but to a lesser degree. There were no significant gross or microscopic pathologic changes detected in the liver. The NOAEL of NPE-4 can be considered to be 40 mg/kg bw/d based on no systemic effects observed in the low dose group (Smyth HF et al.,1969).

NP

A study was conducted to determine the oral toxicity of NP to rat after 28 days of exposure following OECD Guideline 407. Groups of five male and five female Sprague-Dawley rats were exposed to NP via incorporation in the diet at nominal dose levels of 0, 25, 100 or 400 mg/kg bw/d. Clinical signs of toxicity, bodyweight and food consumption were recorded and towards the end of the study routine haematology, blood clinical chemistry and urinalysis examinations were made. A full necropsy was performed on all animals at termination. Adrenals, liver, kidneys and testes with epididymides were weighed and a limited range of major organs was examined microscopically. At 400 mg/kg bw/d, bodyweight gain was significantly reduced for both male and female rats, throughout the study. The amount of food consumed and food utilisation was also reduced at 400 mg/kg bw/d for both sexes. For males at 400 mg/kg bw/d there were slight differences in comparison with the controls for urea and cholesterol levels were increased and glucose levels were reduced. Also, there were increases in the group mean relative kidney, liver and testes weights. Hyaline droplet accumulation was observed in the renal proximal tubules and a minor vacuolation in the periportal hepatocytes for males at 400 mg/kg bw/d. For males at 25 and 100 mg/kg bw/d, minor increases in comparison with the concurrent control group were reported for kidney, adrenal and liver weights and minimal hyaline droplet formation was detected in the kidney. Based on the above result, the NOAEL of NP for repeated dose toxicity was determined to be 100 mg/kg bw/d (Hüls AG, 1989).

A study was conducted to determine the oral toxicity of NP to rat after 90 days of exposure following U. S. EPA TSCA Guideline (EPA OPPTS 870.3100). The test substance was administered to four groups of Sprague–Dawley Crl: CD BR rats at dietary levels of 0, 200, 650 or 2,000 ppm which corresponded to approximate dietary intakes of 0, 15, 50 or 150 mg/kg bw/d, respectively. There were 25 rats/sex/group in the control and high dose groups and 15 rats/ sex/group in the low and mid dose groups. Ten of the 25 rats/sex in the control and high dose groups were designated as recovery animals and were maintained on control diets for 4 weeks after completion of the 90 d exposure period to assess the reversibility of any effects which might be observed. Clinical signs, bodyweight, organ weight, food consumption, hematology, ophthalmology, clinical chemistry, gross and microscopic pathology were recorded. Estrous cyclicity was monitored using vaginal cytology during 8th week of the study, and sperm count, motility, and morphology were evaluated at termination. In-life effects from para-nonylphenol exposure were limited to small decreases (<10%) in body weight and food consumption in the 2,000 ppm dose group. Postmortem measurements at termination indicated a dose-related kidney weight increase in males and a decrease in renal hyaline globules/ droplets in males from the 2,000 ppm dose group. The kidney weights showed complete recovery following the 4 week post dosing recovery period. Due to the small magnitude of the changes (i. e. all weights were within or near laboratory historical control values) and the lack of correlating clinical or histopathological changes, the kidney weight alterations were not considered toxicologically significant. Renal tubular hyaline droplets is associated with the rat-specific protein, alpha-2u-globulin, and, therefore, this finding was not considered toxicologically relevant to humans. No other effects attributable to para-NP were observed. No changes were observed for estrous cycling, sperm evaluations, or effects on endocrine organs. Based on the minor findings for the 2,000 ppm dose group, the 90 d NOAEL for NP to rat can be considered to be 650 ppm in the diet, corresponding to an approximate intake of 50 mg/kg bw/d (Cunny HC et al., 1997).

Justification for classification or non-classification

NPEO does not require classification according to CLP (EC 1272/2008) and DSD (67/548/EEC) criteria based on results from repeated dose toxicity studies with NPE-4. Further toxicology information available for NP supports the conclusion.