A dried sludge product resulting from the treatment process of domestic wastewater. The exact processes followed for the production of the dried sludge are: Preliminary + secondary treatment of the wastewater stream, thickening, dehydration and drying of the excess sludge.

Endpoint summary

Description of key information

Skin irritation/corrosion:  Skin irritation/corrosion study did not need to be conducted, as available acute toxicity study by dermal route (endpoint 7.2.3) did not indicate skin irritation up to the relevant limit dose level (2000 mg/kg body weight).

Eye Irritation:

Tested according to OECD Test Guideline No. 437 :

Damage by the test item is assessed by quantitative measurements of changes in corneal opacity and permeability with an opacitometer and visible light spectrophotometer, respectively. Both measurements are used to calculate an IVIS (In Vitro Irritancy Score), which is used to assign an in vitro irritancy hazard classification category for prediction of an in vivo ocular irritation of the test item.
Eyes were collected by slaughterhouse employees. The eyes were enucleated as soon as possible after death. The eyes, once they arrive at the laboratory, were carefully examined for defects including scratched, and neovascularisation. Only corneas from eyes free of such defects were used. Nine corneas were used for the study. Isolated corneas were mounted in specially designed corneal holders that consisted of anterior and posterior compartments respectively. Both chambers were filled to excess with pre-warmed Eagle's Minimum Essential Medium (EMEM). The device was then equilibrated at 32 ± 1°C for at least one hour in water bath to allow the corneas to equilibrate with the medium and to achieve normal metabolic activity, to the extent possible. Fresh pre-warmed EMEM was added to both chambers and baseline opacity readings were taken for each cornea. The testing was performed on three groups of corneas: test item treatment group, positive control group (20% w/v imidazole in 0.9% NaCl solution) and negative control group (0.9% NaCl solution). Each test group consisted of the three corneas.
The test item was tested as suspension prepared from test item at 20% concentration in a 0.9% sodium chloride solution. 2g of the test item was suspended in 10 mL of 0.9% sodium chloride solution. The open-chamber method was used, because the test item solution was not applicable by micropipette. The test item (enough to completely cover the cornea) was applied directly to the epithelial surface of the cornea using inject syringe. After dosing, the glass window was replaced on the anterior chamber to recreate a closed system. The controls were included in the BCOP test method so that nonspecific changes in the test system could be detected and to provide a baseline for the assay endpoints. Appearance of corneas was observed before and after application of the test item, negative and positive control. No macroscopic damage was observed on corneas before application. Corneal opacity was observed on the corneas treated by the positive control. The corneas treated by test item and negative control were without macroscopic damage.
The opacity and permeability of each cornea were recorded. The In Vitro Irritancy Score (IVIS) was calculated from the values of opacity and permeability. The study met all the acceptance criteria for positive and negative controls. The In Vitro Irritancy Score (IVIS) for Dried Sludge from domestic wastewater was 1.00. This value of IVIS is ≤ 3 therefore the classification of test item effect according to UN GHS criteria for eye irritation or serious eye damage is: No category.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15.09.2021-16.09.2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

GLP compliance:

yes (incl. QA statement)

Species:

cattle

Strain:

other: Bovine

Vehicle:

physiological saline

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

The test item was tested as suspension prepared from test item at 20% concentration in a 0.9% sodium chloride solution.
2g of the test item was suspended in 10 mL of 0.9% sodium chloride solution.

Duration of treatment / exposure:

4 hours

Duration of post- treatment incubation (in vitro):

1.5 hours

Number of animals or in vitro replicates:

3

Details on study design:

Scheme
Selection of corneas, mounting in holders → incubation with EMEM 1hour (32 ± 1°C) → removed EMEM, measurement of baseline opacity → treatment by positive and negative control substances and test item (incubation 4 hours) → washing of epithelium, measurement of opacity after application → application of sodium fluorescein (5 mg/ml), incubation 1.5 hour (32 ± 1°C) → measurement of absorbance (490 nm).

Irritation parameter:

in vitro irritation score

Value:

1

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Interpretation of results:

GHS criteria not met

Conclusions:

The study met all the acceptance criteria for positive and negative controls. The In Vitro Irritancy Score (IVIS) for test item, Dried Sludge from domestic wastewater was 1.00.
This value of IVIS is ≤ 3 therefore the classification of test item effect according to UN GHS criteria for eye irritation or serious eye damage is: No category.

Executive summary:

The test item, Dried Sludge from domestic wastewater, was tested for the potential to cause ocular corrosivity or severe irritancy, as measured by its ability to induce opacity and increased permeability in an isolated bovine cornea. The test was performed according to OECD Test Guideline No. 437 (2017) and Method B.47 Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage, Commission Regulation (EU) 2017/735, Adopted 14th February 2017.

The testing was performed on three groups of corneas: test item treatment group, positive control group (20% w/v imidazole in 0.9% NaCl solution) and negative control group (0.9% NaCl solution). Three corneas per group were used.

The open-chamber method was used, because the test item solution was not applicable by micropipette. The test item (enough to completely cover the cornea) was applied directly to the epithelial surface of the cornea using inject syringe.
Corneas were exposed for 4 hours.

The opacity and permeability of each cornea were measured. The In Vitro Irritancy Score (IVIS) was calculated from the values of opacity and permeability.

The study met all the acceptance criteria for positive and negative controls. The In Vitro Irritancy Score (IVIS) for Dried Sludge from domestic wastewater was 1.00.

This value of IVIS is ≤ 3 therefore the classification of test item effect according to UN GHS criteria for eye irritation or serious eye damage is: No category.

 

 

 

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The substance is not classified as an irritant according to the CLP regulation as:

• no adverse effects were observed in the Eye irritation study (OECD Test Guideline No. 437)


• no skin irritation effects were observed up to the limit dose level of 2000mg/kg body weight in acute toxicity study conducted by dermal route (OECD Guideline 402)