Zinc O,O,O',O'-tetrakis(1,3-dimethylbutyl) bis(phosphorodithioate)

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:

0.074 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.007 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:

0.01 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 this substance are available for evaluating biodegradation, metabolism, and toxicity to aquatic vertebrate and invertebrate species.

 

An analog of this substance, EC 283-392-8, was not ready biodegradable when tested in accordance with OECD Guideline 301B (Schaefer, EC and Haberlein, D, 1998). 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%.

 

This substance caused a significant adverse effect on the oxygen consumption of the microbes associated with the activated sludge (Goodrich, MS, 1994; OECD Guideline 209). The EC₅₀for inhibition of metabolism, as represented by respiration, was calculated to be greater than 10,000 mg/l. . 

 

The acute aquatic toxicity of an analog ofthis substance, EC 283-392-8,was evaluated using rainbow trout and was conducted in accordance withOECD Guideline 203 (Goodband, TJ, 2001). The 96 h LL (Lethal Loading Rate) 50 value of the substance was determined to be 4.5 mg/l. The NOEL was 1.8 mg/l. The 96 h LC50 and NOEL values for an analog of this substance with the saltwater speciesCyprinodon variegataswas determined to be 46 mg/l and less than 26 mg/l, respectively. 

 

Then acute toxicity of an analog of this substance, EC 283-392-8,also was evaluated inDaphnia(Goodband, TJ, 2005; OECD Guideline 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, EC 283-392-8,was evaluated in freshwater algae in accordance with OECD Guideline 201 (Vryenhoef, H, 2005). 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 has acute aquatic toxicity between 1-10mg/L in the most sensitive species, is not readily biodegradable, and has a measured log Kow of 2.21. Therefore, this substance is classifiable to the aquatic environment ( Aquatic Chronic Category 2a) ccording to the EU CLP (Regulation (EC) No. 1272/2008).