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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

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

Additional ecotoxological information

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Administrative data

additional ecotoxicological information
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
supporting study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: No guideline study, but reported research was conducted according to scientifically justified methods
Justification for type of information:
see attachment “Read-across concept – Human Health/Environment - Category approach for Inorganic sulfites/thiosulfates/dithionite" in section 13.

Data source

Reference Type:
Application of ammonium thiosulfate for blossom thinning in apples
Janoudi A, Flore JA
Bibliographic source:
Scientia Horticulturae 104, 161-168

Materials and methods

Test material

Constituent 1
Chemical structure
Reference substance name:
Ammonium thiosulphate
EC Number:
EC Name:
Ammonium thiosulphate
Cas Number:
Molecular formula:
diammonium thiosulfate

Results and discussion

Any other information on results incl. tables

The results of this study indicate that the thinning activity of ammonium thiosulfate (ATS) is correlated with drying times of the spray, which in turn is a function of air relative humidity and temperature at the time of application. THe effect of relative humidity on the activity of ATS can be countered by an increase in the concentration of ATRS in the spray solution. Results also indicate that the tinning activity of ATS is a consequence of its action as a caustic agent that destroys floral tissue. Ethylene does not appear to have a major role in the blossom thinning action of ATS. ATS can be a very effective, and safe, thinning agent when applied a petal fall at a concentration of 5% and followed by tree washing with water within 1 hour of application. Delayed washing and higher concentrations of ATS cause excessive thinning and moderate to severe damage to trees. ATS concentration of 1 and 2% resulted in damage ranging from 40 to 86% of all flowers that were open at the time of the treatment.

Applicant's summary and conclusion