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.

Long-term toxicity to fish

Administrative data

Endpoint:

fish, juvenile growth test

Type of information:

experimental study planned

Justification for type of information:

Testing proposal for long-term aquatic toxicity study on fish (OECD 215):

Name of the substance on which testing is proposed to be carried out: Dried Sludge From Domestic Wastewater

According to EU/1907/2006 a long-term toxicity testing on fish is required to be conducted for substances that are to be registered in the tonnage band 100 or higher, if the chemical safety assessment according to annex I indicates the need to investigate further the effects on aquatic organisms. Based on the solubility test conducted, the substance is considered to be highly insoluble and thus the short-term toxicity study is not appropriate to indicate the aquatic toxicity profile of the substance in relation to the examined trophic level (fish). As a result, the short term toxicity test on fish is waived. A testing proposal for a “Fish, juvenile growth” test is made since all the general adaptation possibilities of Annex XI of the REACH Regulation are not adequate to generate the necessary information (see below):

- Available GLP studies
A short-term toxicity study on fish is triggered at a lower tonnage band (Annex VIII). However, due to the insolubility of the dried sludge (<0.5 mg/L), short term tests are not appropriate so as to accurately examine the aquatic toxicity of the substance.

- Available non-GLP studies
No non-GLP study that can fulfill the requirement of Long term toxicity test on fish are available.

- Historical human/control data
No historical human data, such as epidemiological studies on exposed populations, accidental or occupational exposure data and clinical studies are available for the dried sludge from domestic waste. More specifically, none of the following types of human data are available:
• Analytical epidemiology studies on exposed populations
• Descriptive or correlation epidemiology studies
• Case reports describe a particular effect in an individual or a group of individuals exposed to the substance
• Controlled studies in human volunteers
• Information from occupational surveillance
• Postmarketing surveillance data
• Meta-analysis

- (Q)SAR
(Q)SAR models heavily rely on the chemical structure of the examined substance. However, the composition of Dried Sludge from Domestic Wastewater has not been fully identified (approximately 20% remains unknown) and the identified part is expressed in terms of grouping into generic substance categories (proteins, lipids, inorganic content etc.). As a result, (Q)SAR models cannot be used in the specific case to fulfill the requirement of long-term toxicity study.

- In vitro methods
According to ECHA's Guidance R7b there are no EU / OECD guidelines for in vitro test of relevance to aquatic toxicity.

- Grouping and read-across
Considering the technical difficulties that the specific UVCB substance entails (highly insoluble, abundancy of components), the identification was conducted on the basis of identifying general group categories, such as proteins, lipids, inorganic content, water etc. Subsequently, being technically impossible to identify specific compounds, no grouping can be made based on similar physicochemical toxicological, and ecotoxicological properties of substances and no data from other studies could be exploited so as to fulfill the long term aquatic toxicity test on fish requirement.

- Weight of evidence
A weight of evidence approach cannot be adopted since no read across, Q(SAR) model, adequate in vitro methods or human historical data are available so as to support the specific strategy.

- Substance-tailored exposure driven testing
Testing in accordance with Section 9.1.6 of Annex IX could have been avoided based on the exposure scenario developed and by fulfilling the criteria of point 3.2.a. of Annex XI of REACH Regulation. However, no data regarding the aquatic toxicological profile of the substance in relation to fish population are available so as to compute an appropriate PNEC and fulfill the second criteria of the endpoint 3.2.a.
Furthermore, the substance is not incorporated in an article nor strictly controlled conditions as set out in Article 18(4)(a) are implemented, so as to take advantage of either the endpoint 3.2.b or 3.2.c.

The OECD 215 – Fish Juvenile Growth Test is proposed to be conducted so as to fulfill the requirement of long-term toxicity test on fish.

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 215 (Fish, Juvenile Growth Test)

Test material

Test material information

Constituent 1

Reference substance name:

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.

EC Number:

943-834-9

Molecular formula:

Not applicable for UVCB substances

IUPAC Name:

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.

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