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The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Justification for grouping of substances and read-across

There are no valid data available on the chronic toxicity towards aquatic invertebrates and toxicity towards algae and aquatic microorganisms of zinc O, O, O', O'-tetrabutyl bis(phosphorodithioate). In order to fulfil the standard information requirements set out in Annex VIII, Section 8.5.2, in accordance with Annex XI, Section 1.5 of Regulation (EC) No 1907/2006, read-across from a structurally similar substance is conducted.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met. ” In particular for human toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

Having considered the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006, whereby physicochemical, toxicological and ecotoxicological properties may be predicted from data for reference substance(s) by interpolation to other substances on the basis of structural similarity, the substance Phosphorodithioic acid, mixed O, O-bis(1,3-dimethylbutyl and iso-Pr) esters, zinc salts (CAS 84605-29-8) is selected as reference substances for the assessment of chronic toxicity towards aquatic invertebrates and toxicity towards algae and aquatic microorganisms.

The read-across is based on structural similarity as both chemicals belong to the substance class of Zinc alkyldithiophosphates (ZDDP) which are produced by a chemical reaction of Phosphorous pentasulfide with low molecular weight alcohols followed by a subseuqent reaction with zinc oxide. A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

Overview of aquatic toxicity for the target substance Zinc O, O, O', O'-tetrabutyl bis(phosphorodithioate) and the source substance Phosphorodithioic acid, mixed O, O-bis(iso-Bu and pentyl) esters, zinc salts is presented in the following table.

 

Target substance (a)

Source substance (b)

CAS No.

6990-43-8

84605-29-8

Chemical name

Zinc O,O,O',O'-tetrabutyl bis(phosphorodithioate)

Phosphorodithioic acid, mixed O,O-bis(1,3-dimethylbutyl and iso-Pr) esters, zinc salts

Short term toxicity to fish

Experimental result: LC50 = 49 mg/L

Experimental result: LL50 = 4.5 mg/L

Long term toxicity to fish

Data waiving

--

Short term toxicity to aquatic invertebrates

Experimental result: EC50 = 7.3 mg/L

Experimental result: EL50 = 23 mg/L

Long term toxicity to fish/invertebrates

RA: CAS 84605-29-8

Experimental result: NOECreproduction = 0.26 mg/L

Toxicity to aquatic algae

RA: CAS 84605-29-8

Experimental result: ErL50 = 24 mg/L

Toxicity to microorganisms

RA: CAS 84605-29-8

Experimental result: EC50 > 10,000 mg/L

(a) The substance subject to the REACh Phase-in registration deadline of 31 May 2013 is indicated in bold font. Only for this substance a full set of experimental results and/or read-across is given.

(b) Reference (read-across) substance(s) are indicated in normal font. Lack of data for a given endpoint is indicated by “--“.

Discussion:

Acute aquatic toxicity data for the target substance Zinc O, O, O', O'-tetrabutyl bis(phosphorodithioate) and the source substance Phosphorodithioic acid, mixed O, O-bis(iso-Bu and pentyl) esters, zinc salts established that invertebrate (i.e. Daphnia magna) is the most sensitive species with an EC50 (48h) of 7.3 mg/L (nominal). Thus Zinc O, O, O', O'-tetrabutyl bis(phosphorodithioate) is considered to be acutely toxic to aquatic organisms. Effects towards fish and algae were found in the same range providing an LC50 (96h) of 49 mg/L (nominal) for the rainbow trout (Salmo gairdneri) and an EL50 (72h) of 24 mg/L (nominal) for the growth inhibition of the green algae Scenedesmus subspicatus.

Long term data for the source substance Phosphorodithioic acid, mixed O, O-bis(iso-Bu and pentyl) esters, zinc salts towards invertebrate (i. e. Daphnia magna) determined a NOEC for reproduction of 0.26 mg/L (measured). No data on the long-term toxicity on fish is available. However, since daphnids can be considered as more sensitive towards this substance (compared to fish) and for reasons of animal welfare a chronic study with fish is not provided.

No inhibitory effects towards aquatic microorganisms were observed. Therefore, disturbances in sewage treatment plants are not anticipated for this substance.