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Short-term toxicity to aquatic invertebrates

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The assessment entity “tall oil” is a mixture of different saturated and unsaturated C16 -C18 fatty acids. Therefore, the endpoint is addressed with publicly available data on fatty acids with the same or similar structure, including conservatively fatty acids with a shorter chain (i.e. C14) if relevant and appropriate in accordance with previously applied read-across approaches (U.S. EPA Fact Sheet, 2008).

A registration dossier shall contain information on the environmental hazard assessment (Regulation 1907/2006, Article 10). For the environmental hazard assessment of tall oil, the standard testing regime set out in Annexes VII to IX is adapted in accordance with Section 1.2 and 1.3 of Annex XI so that “testing does not appear to be scientifically necessary” as follows:

(I) The ecotoxic potential of the fatty acid (tall oil) is assumed to be negligible. Fatty acids are generally not considered to represent a risk to the environment, which is reflected in their exemption from the obligation to register (Annex V, Section 9 and Regulation (EC) No 987/2008).

(II) Fatty acids are a natural component of soil and water, produced in the cells of plants and animals. Furthermore, fatty acids constitute a significant part of the normal daily diet of mammals, birds and fish (EFSA, 2013). Fatty acids as contained in plant and animal tissue can be expected to also represent a significant part of the normal daily diet of aquatic invertebrates. Fatty acids will be rapidly degraded in soil and water via the β-oxidation pathway (e.g. essential process in the citric acid cycle) and thus are not expected to accumulate in the environment (EU RAR zinc distearate, 2008). Hence, an accumulation in the environment and long-term effects on plants and animals are not expected (Health Canada, 2017).

(III) Earlier assessments indicate that solubility and bioavailability of fatty acids decreases in the water column with increasing chain length (> 12C) (OECD SIDS, 2014; HERA, 2003). “For chain lengths > C12, solubility decreases to a degree where an adverse effect would not be expected in the environment due to reduced bioavailability […] Data for longer chain lengths have been generated using solvents which makes interpretation more difficult” (HERA, 2003). Short-term invertebrate toxicity data were reviewed by HERA (2003). However, HERA (2003) does not specify if effect concentrations were derived from tests in which the fatty acid was applied with a solvent.

(IV) Effect concentrations for the acute toxicity to aquatic invertebrates were reviewed by OECD SIDS (2014), and the review provides additional information including if test concentrations exceeded water solubility limits. Relevant endpoints for the acute toxicity of tall oil to aquatic invertebrates are listed in the Table “Acute toxicity endpoints for aquatic invertebrates reviewed by OECD SIDS (2014) and considered relevant for tall oil” below. The majority of effect concentrations are unbounded and/or above the OECD test limit of 100 mg/L (§ 2, OECD 202, 2004). Thus, the highest test concentration did not cause any toxic effects. Exceptions are the 48h-EC0 of 55 mg/L C18 fatty acid and the 48h-EC50 of 0.695 (measured) tallow fatty acids / C16-18 for the toxicity to Daphnia magna. Whereas the former is above the water solubility limit and not reliable, the latter EC50 is very different from the four other values for the same test and species. Thus, based on a weight of evidence, Daphnia magna is not expected to be sensitive to tall oil.

Table 1: Acute toxicity endpoints for aquatic invertebrates as reviewed by OECD SIDS (2014) and considered relevant for tall oil:

Species

Endpoint [mg/L]

Test item/chain lengths

CAS no.

Remark

Hyale plumulosa

48h-EC50: no mortality at saturation of test item

Tetradecanoic acid / C14

544-63-8

Saltwater, semi-static

Daphnia magna

48h-EC0 ≥ 32 (nominal)

9-Octadecenoic acid, (Z) / C18

112-80-1

Static, concentration above water solubility limit

Daphnia magna

48h-EC0 = 55 (nominal)

9,12-Octadecadienoic acid / C18

60-33-3

Static, concentration above water solubility limit

Daphnia magna

48h-EC50 > 100 (nominal)

Octadecanedioic acid / C18

871-70-5

Static, concentration above water solubility limit

Daphnia magna

48h-EC50 > 100 (nominal)

tallow fatty acids / C16-18

61790-38-3

Static, concentration above water solubility limit

Daphnia magna

48h-EC50 = 0.695 (measured)

tallow fatty acids / C16-18

61790-38-3

Static

 

In summary, tall oil (i.e. C16-18 fatty acids) is expected to be non-toxic to aquatic invertebratesup to and including its water solubility limit.Based on acute effect concentrations available for the aquatic risk assessment, aquatic invertebrates do not appear to be most sensitive. Fatty acids as contained in plant and animal tissue, are a natural component of the environment, represent a significant part of the normal daily diet and are rapidly degraded and therefore not expected to accumulate in the environment.Hence, from a scientific point of view, further tests on the short-term toxicity oftall oilto aquatic invertebrates are not considered to be required.

 

References:

U.S. Environmental Protection Agency, U.S. EPA (2008). Ammonium nonanoate (031802) Fact Sheet, OPP Chemical Code: 031802, p. 2.

Health Canada’s PMRA, Pest Management Regulatory Agency (2017). Ammonium Salt of Fatty Acid Proposed Registration Decision PRD2017-04, p. 36.

OECD SIDS initial assessment profile- aliphatic acids (2014), CoCAM 6 September 30-October 3, Italy/ICCA, p. 41.

HERA (2003). Human & Environmental Risk Assessment on ingredients of European household cleaning products. Fatty Acid Salts (Soap) Environmental Risk Assessment

EU Risk Assessment Report, RAR - Zinc distearate (2008), CAS No. 557-05-1 & 91051-01-3. PART 1 Environment, p. 63.

OECD 202 (2004). OECD Guideline for Testing of Chemicals, Adopted 13 April 2004, Daphnia Sp., Acute Immobilisation Test, p. 12.

EFSA (2013). Conclusion on the peer review of the pesticide risk assessment of the active substance Fatty acids C7 to C18 (approved under Regulation (EC) No 1107/2009 as Fatty acids C7 to C20), European Food Safety Authority, Parma, Italy, Vol 11(1):3023

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