Phosphorodithioic acid, mixed O,O-bis(iso-Bu and pentyl) esters, zinc salts

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

4 µg/L

Assessment factor:

100

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

45 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

4.6 µg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

100 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.024 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.002 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.002 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

10.67 mg/kg food

Assessment factor:

300

Conclusion on classification

Studies of an analog of this substance are available for evaluating biodegradation, metabolism, and toxicity to aquatic vertebrate and invertebrate species.

 

An analog of this substance was not ready biodegradable when tested in accordance with OECD 301B. The mean percent theoretical CO2 evolved for the test substance was 1.5% (range 0.6 to 2.0%). The control chambers evolved an average of 6.5 milligrams of CO2 over the test period. The mean percent theoretical CO2 evolved for the reference substances was 99%.

 

An analog of thissubstance caused a significant adverse effect on the oxygen consumption of the microbes associated with the activated sludge (OECD Guideline 209). The EC₅₀for inhibition of metabolism, as represented by respiration, was greater than 10,000 ppm.  

 

The acute aquatic toxicity of this substance and an analog ofthis substancewas evaluated with fish in accordance withOECD 203. The 96 h LC50 and NOEL values for the this substance with the saltwater speciesCyprinodon variegataswas determined to be 46 mg/l and less than 26 mg/l, respectively. The 96 h LL (Lethal Loading Rate) 50 and NOEL values for the analog with the freshwater speciesrainbow troutwas determined to be 4.5 mg/l and 1.8 mg/l, respectively. 

 

The acute toxicity of an analog of this substance also was evaluated inDaphnia(OECD 202). The 48-Hour EL*50 was determined to be 23 mg/L nominal loading rate and the No Observed Effect Loading rate was 10 mg/l nominal loading rate.

 

The acute toxicity of an analog of this substance was evaluated in freshwater algae in accordance with OECD Guideline 201. Exposure ofScenedesmus subspicatusto the test material gave an EbL50 (72h) value of 21 mg/L loading rate WAF and an ErL50 (0-72hr) value of 24 mg/L loading rate WAF. The No Observed Effect Loading rate was 10 mg/L loading rate WAF.

 

Based on the available environmental fate and ecotoxicological data for daphnids, fish and algae, this substance needs to be classified as to the aquatic environment according to Directive 67/548/EEC,  the EU CLP (Regulation (EC) No. 1272/2008).  This substance has acute aquatic toxicity between 1-10mg/L in the most sensitive species, is not readily biodegradable, and has a log P ≤3.0.