2,6-dibromo-4-cyanophenyl heptanoate

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

The PBT Assessment is based on the criteria set out in the “Guidance on information requirements and chemical safety assessment, Chapter R.11: PBT Assessment” (ECHA, 2017).

 

Persistence (P) Assessment

2,6-dibromo-4-cyanophenyl heptanoate (CAS 56634-95-8) is considered to be not readily biodegradable. based on data available for the structural analogue 2,6-dibromo-4-cyanophenyl octanoate (37 % b in 28 days; OECD 301B). The assessment of the biodegradation in water/sediment is based on data available for the structural analogue 2,6-dibromo-4-cyanophenyl octanoate in a simulation study, according to GLP and BBA Part IV. A degradation half-life ranging from 4.2 to 8.5 hours (recalculated to 12 °C) was determined for the read-across substance 2,6-dibromo-4-cyanophenyl octanoate. The main degradation product in water and sediment was 3,5-dibromo-4-hydroxybenzonitrile. After 100 days 14CO2 formation accounted for 55.2 and 55.4% AR. The degradation half-life of the main degradation product 3,5-dibromo-4-hydroxybenzonitrile ranged from 8.5 to 36 days (recalculated to 12 °C).

The degradation of the transformation product and structural analogue [14C]-3,5-dibromo-4-hydroxybenzonitrile (CAS 1689-84-5) was investigated in natural water samples under aerobic conditions. Under the conditions of the test 3,5-dibromo-4-hydroxybenzonitrile remained stable (DT50 = >1000 days).

The assessment of the biodegradation in soil is based on data available for the structural analogue 2,6-dibromo-4-cyanophenyl octanoate. A half-life of 0.14 – 0.62 days (0.28 – 1.25 days, recalculated to 12 °C) in three different soils was determined. After 35 days 29.4 – 55.1% of the applied radioactivity were mineralized.

Based on the available data on the degradation product 3,5-dibromo-4-hydroxybenzonitrile, the target substance 2,6-dibromo-4-cyanophenyl heptanoate is assessed as vP/P.

 

Bioaccumulation (B) assessment

The experimentally determined log Pow of 5.4 of 2,6-dibromo-4-cyanophenyl heptanoate (CAS 56634-95-8) indicates a potential for bioaccumulation. However, a study on the bioconcentration in fish, available for the structural analogue 2,6-dibromo-4-cyanophenyl octanoate (CAS 1689-99-2), determined a BCF of 180 ± 40 (whole fish). Based on the available read-across data 2,6-dibromo-4-cyanophenyl heptanoate does not meet the B criterion.

 

Toxicity (T) assessment

The substance is classified as H361d (“Suspected of damaging the unborn child”) and thus assessed as T.

Effect concentrations determined in chronic aquatic toxicity tests were < 0.01 mg/L.

 

 

Summary and overall conclusions on PBT or vPvB properties

 

Overall conclusion:

Based on the assessment described in the subsections above the substance is not PBT.

 

Justification:

According to Annex XIII of the REACH Regulation (EC) No 1907/2006, a PBT substance has to meet all three of the criteria for persistence, bioaccumulation and toxicity, as listed in part 1 of Annex XIII, and a vPvB substance has to meet all criteria for persistence and bioaccumulation, as listed in part 2 of Annex XIII. Based on the relevant data provided and discussed, the substance is identified as vP and T, the substance is not identified as PBT or vPvB.