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Ecotoxicological information

Ecotoxicological Summary

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Hazard for aquatic organisms

Hazard for air

Hazard for terrestrial organisms

Hazard for predators

Additional information

Read-across approach

The assessment of the environmental effects, exposure and risks of Fatty acids, C16 -18, barium salts is based on the assessment of the individual moieties of the barium carboxylate salt, i.e. the barium ion and the Fatty acids, C16-18.This read-across approach from data for both constituent ions is considered more adequate for the purpose of classification and labelling and environmental risk assessment compared to testing of the registered substance itself:

  • Upon dissolution in water, it is indeed predicted that metal carboxylates dissociate completely into the metal cation and the organic anion at environmentally relevant conditions. No information is available on the stability constants of fatty acids, C16-18, barium salts, but predictions of stability of other barium carboxylates (Ba propionate, Ba valerate and Ba isovalerate) in a standard ISO 6341 medium (2 mM CaCl2, 0.5 mM MgSO4, 0.77 mM NaHCO3 and 0.077 mM KCl, pH 6 and 8) clearly show that monodentate ligands such as carboxylic acids have no potential for complexing barium ions in solution (<1% of total metal concentration complexed at 0.001 mM Ba;Visual minteq. Version 3.0, update of 18 October 2012.http://www2.lwr.kth.se/English/OurSoftware/vminteq/index.html). It is therefore concluded that upon release to the environment and dissolution in aqueous media, fatty acids, C16 -18, barium salts will dissociate and only be present under its dissociated form, i.e. as barium cation and C16-18 carboxylate anions.
  • Upon dissolution and dissociation of fatty acids, C16 -18, barium salts into Ba2+and C16-18 carboxylate anions, both constituent ions will each show its proper (bio)degradation, bioaccumulation and partitioning behaviour in the environment. The environmental fate and behaviour for the metal and organic moieties is predicted to be clearly different from each other, resulting in a different relative distribution over the environmental compartments (water, air, sediment and soil). Because the relative exposure to both constituent ions is hence predicted to be different from the original composition of fatty acids, C16-18, barium salts, data for the ecotoxicological properties of fatty acids, C16-18, barium salts tested as such are considered less relevant for effects and risk assessment and a read-across approach from separate data for both the barium cation and C16-18 carboxylate anions is preferred.

Based on the following weight of evidence, the risks of fatty acids, C16 -18 are predicted to be negligible and therefore fatty acids C16 -18 are not considered in the effects assessment for its barium salts:

  • The substance fatty acids, C16 -18 is not classified as dangerous under the EU CLP regulation (EC 1272/2008) and is no PBT or vPvB substance.
  • The substance fatty acid, C16-18 has a low exposure potential to the environment since it can be considered as readily biodegradable under aerobic conditions (EPI Suite 4.0, BIOWIN v4.10) and has a low solubility in water (< 1 mg/L).
  • Fatty acids are generally not considered to represent a risk to the environment, which is reflected in their exemption from the obligation to register under REACH according to REACH Annex V, section 9 (Regulation (EC) No 987/2008).
  • The United States Environmental Protection Agency report “Screening-level hazard characterization and prioritization document N-alkyl carboxylic acids, 23 chemicals” (available at http://www.epa.gov/chemrtk/hpvis/rbp/n-Alkyl%20Carboxylic%20Acids_HBP_December%202008.pdf) shows available measured or predicted toxicity data for N-alkyl-carboxylic acids with a wide range of chain lengths. The available information for fatty acids, C16-18 does not predict effects at saturation. It must be noted that no measured chronic toxicity data are available and all data on chronic toxicity of these N-alkyl-carboxylic acids are based on predictions with ECOSAR. Further, it is clearly noted in this report that “carboxylic and fatty acids are expected to undergo rapid biodegradation in the environment and are metabolized and used as a source of cellular energy in biota, both of which limit the potential for chronic effects.“ Therefore it can be concluded that there are no concerns on chronic toxicity of fatty acids, C16-18 to aquatic organisms.
  • The Environmental risk assessment of Fatty Acid Salts (Soap) published by the Human & Environmental Risk Assessment (HERA) on ingredients of European household cleaning products in September 2003 (available at http://www.heraproject.com/files/5-E-04-%20HERA%20Fatty%20acid%20salts%20Env%20web%20wd.pdf) also states that all measured toxicity data of fatty acids, C16-18 to aquatic organisms are considerably greater than the estimated solubility for C16 and C18. It must be noted that only acute toxicity data are available for fatty acids with chain lengths between C16 and C18. Based on the predicted data in the USEPA report, the acute-to-chronic ratio is approximately a factor 10, and therefore predicted chronic toxicity data for fatty acids, C16-18 are also still expected above the solubility limit.
  • The disseminated information on the ECHA website on the registration dossier for Fatty acids, C16-18 (CAS67701-03-5) and hexadecanoic acid (palmitic acid, CAS No 57-10-3) do not report any classification nor PNEC values for environmental endpoints.

 

Therefore, the assessment of Fatty acids, C16 -18, barium salt is only based on the barium ion.

For most metal-containing compounds, it is the potentially bioavailablemetal ion that is liberated (in greater or lesser amounts) upon contact with water that is the moiety of ecotoxicological concern. The solubility of fatty acids, C16-18, barium salts (see IUCLID section 4.8) is above the range of effects concentrations for dissolved Ba in the aquatic environment (PNECfreshwater for Ba = 227.8 µg Ba/L) and therefore ecotoxicity data for soluble Ba salts can be directly used in a read-across approach for fatty acids, C16-18, barium salts.

Conclusion on classification

The substance Fatty acids, C16-18, barium salts will dissociate into barium and C16-18 carboxylate ions after dissolution in water and hence can be regarded as a mixture of both constituent ions. In the absence of toxicity data for Fatty acids, C16-18, barium salts itself, its classification for environmental hazards is based on the classification of its moieties (barium and fatty acids, C16-18). Both barium and fatty acids, C16-18 are not classified as hazardous to the aquatic environment, and according to the summation method, it is therefore concluded that the substance Fatty acids, C16-18, barium salts is not hazardous to the aquatic environment.