Isovaleric acid

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

29.3 µg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.293 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

2.93 µg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

22.4 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

117.3 µg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

11.7 µg/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:

6.25 µg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Deduction of PNECs is based on the Guidance Document "Guidance on information requirements and chemical safety assessment - Chapter R.10: Characterisation of dose[concentration]-response for environment" (TGD R.10) published by the European Chemicals Agency, 2008.

PNECs sediment and soil are derived using the equilibrium partitioning method. Values of Koc and Henry's Law constant are taken from the respective sections of IUCLID (Sect. 5.4.1 and Sect. 5.4.2). Estimates of Koc are calculated with the program KOCWIN v2.00 within US EPA EPI Suite v4.10 (GUBDH, 2012). Henry's Law constant was experimentally determined (Khan, 1992)

 

PNEC aqua (freshwater)

L(E)C50 values were determined using data from supporting substances. Data are available for all three trophic levels.

                                                                              Valeric acid              Isobutyric acid               Conversion to Isovaleric acid

Short-term toxicity to fish                                          77 mg/L                                                                        77 mg/L

Short-term toxicity to aquatic invertebrates                                                 51.25 mg/L                                 59.4 mg/L

Toxicity to aquatic algae and cyanobacteria           29.3 mg/L                                                                       29.3 mg/L

The lowest value (29.3 mg/L) was taken for derivation of PNECs aqua.

 

PNEC sediment (freshwater)

According to chapter R.10.5.2.1 of TGD R.10, the PNEC sediment can provisionally be calculated in the absence of data for sediment-dwelling organisms using the equilibrium partitioning method (EPM).

PNEC derivation following procedures of TGD R.10 and R.16:

PNEC aqua (freshwater): 29.3 µg/L,

Koc: 4.022 (US EPA EPI Suite estimate, program KOCWIN v2.00, Koc estimate from lMCI; see IUCLID Sect. 5.4.1);

The PNEC sediment (freshwater) was calculated to 25.5 µg/kg ww. This value was converted to dry weight (conversion factor of 4.6) resulting in a PNEC sediment (freshwater) of 117.3 µg/kg sediment dw.

 

PNEC sediment (marine water)

According to chapter R.10.5.2.1 of TGD R.10, the PNEC sediment can provisionally be calculated in the absence of data for sediment-dwelling organisms using the equilibrium partitioning method (EPM).

PNEC derivation following procedures of TGD R.10 and R.16:

PNEC aqua (marine water): 2.93 µg/L,

Koc: 4.022 (US EPA EPI Suite estimate, program KOCWIN v2.00, Koc estimate from MCI; see IUCLID Sect. 5.4.1);

The PNEC sediment (marine water) was calculated to 2.55 µg/kg ww. This value was converted to dry weight (conversion factor of 4.6) resulting in a PNEC sediment (marine water) of 11.7 µg/kg sediment dw.

 

PNEC soil

According tochapter R.10.6.1 of TGD R.10, the PNEC soil can provisionally be calculated in the absence of data for soil organisms using the equilibrium partitioning method (EPM).

PNEC derivation following procedures of TGD R.10 and R.16:

PNEC water (freshwater): 29.3 µg/L,

Koc: 4.022 (US EPA EPI Suite estimate, program KOCWIN v2.00, Koc estimate from MCI; IUCLID Sect. 5.4.1),

HLC: 0.0844 Pa*m³/mol (Khan 1992; IUCLID Sect. 5.4.2);

The PNEC soil was calculated to 5.53 µg/kg ww. This value was converted to dry weight (conversion factor of 1.13) resulting in a PNEC soil of 6.25 µg/kg soil dw.

 

Secondary poisoning

Isovaleric acid is readily biodegradable. Calculated BCF values are low (3.16 and 2.11 L/kg - calculated with the programs US EPA EPI Suite and US EPA TEST, respectively). Combined data indicate a low potential for bioaccumulation. There is no concern about toxic effects resulting from exposure via the food chain.