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EC number: 215-662-8 | CAS number: 1338-24-5
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Endpoint summary
Administrative data
Description of key information
Additional information
For the key short-term studies of fish, daphnia and algae, the same naphthenic sample is used. These samples are a good representative for the naphthenic acids of the current registration dossier because of comparable specifications of the acidic fraction, which is the main fraction. Specifications of the non-acidic part of the naphthenic acids used for the ecotoxicity testing are not reported.
For both naphthenic acids, the predominant number of saturated rings is 0 -3. The predominant C-range of the naphthenic acids in this dossier is C8-C20 (cut-off is ≥5% of the 90thpercentile), while in the ecotoxicity tests, the range was C6-C16 (cut-off unknown). In general, the higher the C-number, the lower the solubility and log Kow (IUCLID section 4.7) and hence the bioavailability for aquatic organisms. Substances in the higher C-range may become too insoluble to exert ecotoxicity. Hence the naphthenic acids used for the ecotoxicity testing can be considered to be conservative enough regarding ecotoxicity of naphthenic acid in the current dossier.
Table 1 presents the predominant approximate C-range and ring distribution for the naphthenic acids of the ecotoxicity key studies and of the current dossier.
NA specifications |
NA used in key studies on ecotoxicity |
NA in current registration dossier |
Predominant C-range |
C6-C16 |
C8-C20 |
Approximate saturated ring distribution |
0 rings 24% 1 ring 39% 2 rings 30% 3 rings 5% 4 rings 2% |
0 rings 16% 1 ring 32% 2 rings 24% 3 rings 10% 4 rings 3% |
Table 1: Specifications of naphthenic acids (NA) used for ecotoxicity testing and NA of the current registration dossier
The effect of the water accommodated fraction (WAF) of naphthenic acids (NA)on the aquatic organismsPseudokirchneriella subcapitata,Daphnia magna and Pimephales promelas were measured. The test protocols were according to OECD guidelines and the tests were performed according to GLP principles.The test results can be considered as reliable.
For algae a static set up was used, for daphnia and fish a semi static set up was used with medium renewal every 24 hours. Analytical results are available for all 3 studies. Effect values are expressed both in loading rate and in measured dissolved concentration.
A long-term daphnia study was performed following the OECD guideline No 211. No effects were seen up to a concentration of 4.1 mg/L.
Although, no guidelines were followed four long-term fish studies (literature data) were available. No effects were seen up to a concentration of 1 mg/L. Based on the available information (no long-term effects for aquatic invertebrates and no effects seen in the supporting studies for long-term fish), the long-term toxicity test to fish can be waived.Also data on microbial toxicity (Vibrio fisheri) are reported In literature for NA surrogates. In the microtox assay the EC50 for cyclohexane carboxylic acid was 0.07 mM ( 13.0 +/- 1.6 mg/L).
From biodegradation tests it can also be concluded that NA are not toxic to microbial communities.
Enrichment cultures, obtained from an active tailings settling pond, using commercially available NAs as the sole carbon source, resulted in the isolation of a co-culture containingPseudomonas putidaandPseudomonas fluorescens. These microorganisms are not affected by the presence of naphthenic acid.
Also in other biodegradation tests using naphthenic enrichement cultures show the survival ofPseudomonas stutzeriandAlcaligens denitrificans. And in yet another enriched cultureAcinetobacter calcoaceticusand a member of thePseudomonas fluorescensgroup were demonstrated. From these tests it can be concluded that microbial populations are able to survive naphthenic acid exposure.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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