Diisopropylbiphenyl and triisopropylbiphenyl

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.126 µg/L

Assessment factor:

50

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

1.3 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.013 µg/L

Assessment factor:

500

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

1 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

1 481 µg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

148.1 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:

295.3 µg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

1 mg/kg food

Assessment factor:

300

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 aqua are derived from aquatic toxicity data for di-IPB/tri-IPB applying the appropriate assessment factors.

PNECs for sediment and soil are calculated using the equilibrium partitioning method. For these calculations, values for Koc and Henry's Law Constant (HLC) are required in addition to PNECs aqua. Values for Koc and HLC (see IUCLID Sect. 5.4.1 and Sect. 5.4.2) were estimated by calculation using the estimation program US EPA EPI Suite v4.1.

PNECs aqua (freshwater)

For di-IPB/tri-IPB short-term toxicity data are present for aquatic invertebrates and fish (studies according to OECD TG 202 and 203). In addition, NOECs were obtained in an algal growth inhibition test according to OECD TG 201 and a daphnia immobilisation and reproduction test according to OECD TG 201, Part II (1984). Tests were performed with concentrations close to the water solubility of the test substance. Depending on the adjustment and performance of the diluter system, the resulting concentrations were slightly different without biological relevance of the results obtained.

(values in µg/L)                                                              E/LC50     E/LC0     NOEC

Short term toxicity test to fish (96 h):                               > 8.24       8.24

Short term toxicity test to aquatic invertebrates (48 h):   > 4.52       4.52

Algal growth inhibition test (72 h):                                   > 10.1                      10.1

Daphnia immobilisation and reproduction test                                                  6.3

There are toxicity data for all three trophic levels. In addition to short-term tests, a long-term study with daphnia has been performed. NOECs are available for algal growth inhibition and daphnia reproduction. As no adverse effects could be observed in any of the tests conducted at the concentrations applied, and two long-term results are available, an assessment factor of 50 (see Guidance Document Chapter R.10.3.1.2. Table R10-4) is applied on the lowest long-term result (daphnia reproduction test, NOEC = 6.3 µg/L) to generate the PNEC aqua (freshwater). An additional short-term daphnia study conducted with the WAF from a loading of 100 mg/L confirms the absence of toxicity under test conditions close to saturation (Aniol/STZ 2011a).

PNEC aqua (marine water)

For di-IPB/tri-IPB, toxicity data with marine species are not available. The NOEC from the daphnia reproduction test (6.3 µg/L, lowest NOEC) is taken to derive the PNEC (aqua marine water). To compensate for a wider diversity of taxonomic groups and to allow for a broader distribution of sensitivities in the marine environment, an assessment factor of 500 is applied according to Guidance Document Chapter R.10.3.2.3, Table R10-5.

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): 0.126 µg/L,

Koc:117,517 L/kg (US EPA EPI Suite estimate, program KOCWIN v2.00, Koc estimate from the Molecular Connectivity Index, MCI; see CSR Sect. 4.2.1. / IUCLID sect. 5.4.1);

The PNEC sediment (freshwater) was calculated to 322.0 µg/kg ww. This value was converted to dry weight (conversion factor of 4.6) resulting in a PNEC sediment (freshwater) of 1481.2 µg/kg sediment dw.

PNEC sediment (marine water)

According to chapter R.10.5.3.1 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): 0.0126 µg/L,

Koc: 117,517 L/kg (US EPA EPI Suite estimate, program KOCWIN v2.00, Koc estimate from the Molecular Connectivity Index, MCI; see CSR Sect. 4.2.1. / IUCLID Sect. 5.4.1).

The PNEC sediment (marine water) was calculated to 32.2 µg/kg ww. This value was converted to dry weight (conversion factor of 4.6) resulting in a PNEC sediment (marine water) of 148.12 µg/kg sediment dw.

PNEC soil

According to chapter 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): 0.126 µg/L,

Koc: 117,517 L/kg (US EPA EPI Suite estimate, program KOCWIN v2.00, Koc estimate from the Molecular Connectivity Index, MCI; see CSR Sect. 4.2.1 / IUCLID Sect. 5.4.1),

HLC: 1028 Pa*m³/mol (US EPA EPI Suite estimate, program HENRYWIN v3.20, calculated using User-entered (measured) values for vapour pressure (VP) and water solubility (WS); CSR Sect. 4.2.2. / IUCLID Sect. 5.4.2);

The PNEC soil was calculated to 261.32 µg/kg ww. This value was converted to dry weight (conversion factor of 1.13) resulting in a PNEC soil of 295.3 µg/kg soil dw.

Conclusion on classification

The substance has been tested at concentrations that were maximally achievable under test conditions within maximum water solubility, all of them except the algal test under flow-through conditions. Acute aquatic toxicity studies covered the three trophic levels. Long-term data is available from daphnia (21-d reproduction test). The studies failed to reveal aquatic toxicity at the achievable water levels. This is confirmed by screening tests in daphnia and alga, using the WAFs from loadings of 100 mg/L test substance (STZ 2011a,b).

Despite the exonerating evidence of very low potential for aquatic toxicity, but in regard to some uncertainty about the bioaccumulation potential as well as the biodegradation profile of di-IPB/tri-IPB, the substance has provisionally been allocated to

- Cat. Chronic 4, H 413(May cause long lasting harmful effects to aquatic life)according to Regulation (EC) No. 1271/2008