Potassium thiosulphate

Additional ecotoxological information

Administrative data

Endpoint:

additional ecotoxicological information

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

supporting study

Reliability:

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

Reference Type:

publication

Title:

Application of ammonium thiosulfate for blossom thinning in apples

Author:

Janoudi A, Flore JA

Year:

2005

Bibliographic source:

Scientia Horticulturae 104, 161-168

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

Ammonium thiosulphate

EC Number:

231-982-0

EC Name:

Ammonium thiosulphate

Cas Number:

7783-18-8

Molecular formula:

H3N.1/2H2O3S2

IUPAC Name:

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.