Pitch, petroleum, arom.

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

3.5 ng/L

Assessment factor:

10

Extrapolation method:

assessment factor

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

1.54 ng/L

Assessment factor:

10

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

3.6 mg/L

Assessment factor:

10

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.291 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.128 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:

3.64 µg/kg soil dw

Assessment factor:

50

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

0.097 mg/kg food

Assessment factor:

30

Additional information

Pitch, petroleum, arom, (petro pitch) is an UVCB substance of variable composition. It consists of a complex mixture of polycyclic aromatic hydrocarbons (PAH), predominantly of highly condensed aromatic ring systems forming an inert matrix. This matrix is not accessible by common analytical tools (see Chapter 9.0.2.). The substance is scarcely soluble in water. Solubility in organic solvents (e.g. toluene or quinoline) is limited. The 16 EPA-PAH are present in a concentration of up to 2 %. Maximum concentration of benzo[a]pyrene is 0.14 % (see CSR Chapter 1.2.).

Regarding properties and composition of constituents, petro pitch is very similar to the substance pitch, coal tar, high temp. (coal tar pitch) except that concentrations of individual PAH are considerably lower in petro pitch than in coal tar pitch. Due to their similarity, coal tar pitch can be uses as supporting substance to characterise environmental toxicity of petro pitch.

Because solubility of petro pitch in water is very poor and the soluble fraction is variable depending on loading, tests for aquatic toxicity were performed using water accommodated fractions. Petro pitch did not produce noticeable acute aquatic toxicity under standard test conditions in daphnia and algae at nominal concentrations of 100 mg/L (loadings). The same result was found for fish using coal tar pitch as supporting substance. In addition, significant chronic toxicity was not observed at nominal concentrations (loadings) of 100 mg/L (daphnia, supporting substance pitch, coal tar, high temp.) (see CSR Sect. 7.1.). Long-term studies in fish are not available. However, they are not supposed to generate chronic toxic effects that are relevant for classification.

Data on terrestrial toxicity of petro pitch itself is not available. But as for aquatic toxicity, terrestrial toxicity of petro pitch itself is considered to be low as effects are determined in tests requiring distribution and absorption of active substance in dissolved form.

During manufacture and use of petro pitch, PAH may be released into the environment. Degree will be very limited due to the substance characteristics of petro pitch. PAH are known to exert adverse effects to the environment. In the absence of significant environmental toxicity of petro pitch itself, PAH will be used as surrogate to assess a possible impact of petro pitch on environmental protection targets.

Benzo[a]pyrene is one of the best characterised PAH components in petro pitch. It is one of the environmentally most toxic PAH. Based on its concentration in petro pitch and its high environmental toxicity, benzo[a]pyrene is selected as marker substance for the environmental assessment of petro pitch.

As basis for the environmental assessment of petro pitch, PNECs for benzo[a]pyrene are derived in a first step based on experimental results originating from tests with the pure substance benzo[a]pyrene. Derivation of PNECs is performed according to ECHA guidance documents.

In a second step, benzo[a]pyrene PNECs are extrapolated to PNECs valid for total petro pitch. In a simplified approach, similar environmental effects are supposed for benzo[a]pyrene and the other EPA-PAH present in petro pitch. This is considered justified because the overall effect of individual PAH assumed to result from toxicity and quantity are assessed to be similar in petro pitch. A linear extrapolation is performed based on the concentrations of benzo[a]pyrene and total EPA-PAH in petro pitch (0.14 % and 2 % respectively). Thus, benzo[a]pyrene specific PNECs are reduced by a factor of 0.14/2 (0.07) to obtain PNECs representing total pitch, petroleum, arom.

The resulting petro pitch PNECs are displayed in the table above. Under the related fields 'Remarks/Justification', more detailed information on PNEC derivation is provided. These PNECs will be used in the exposure assessment and risk characterisation in CSR Chapter 9 and 10.

Conclusion on classification

Because pitch, petroleum, arom. (petro pitch) is a UVCB substance, it is very difficult to classify it on the basis of the individual components. In addition, not all the components can be analysed when diluted in water. The composition in the water phase will not be the same at different loadings. As recommended for oil products and products such as creosote in the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures (OECD, 2000), the water-accommodated fraction (WAF) approach is considered most appropriate to classify petro pitch. The classification criteria are applied to the loading rate.

Petro pitch produced no acute aquatic toxicity under standard test conditions in daphnia (OECD TG 202) and in algae (OECD TG 201). Read across is made to coal-tar pitch for acute data on fish. All the effective loadings, EL50/LL50 values, were consistently higher than 100 mg/L.

Furthermore, pitch has no bioaccumulation potential.

In accordance to Regulation (EC) No. 1272/2008, there is no need to classify petro pitch for acute toxicity based on these data. Yet, it is recommendable to classify petro pitch for long-term aspects as a potential source of environmental release of PAHs, which may be a cause of concern. This precautionary principle is covered by the “safety net” classification (Category: Chronic 4) [GHS Guidance, part 4, 4.1.2.12], hence H413 Chronic 4 is proposed.

“Poorly soluble substances for which no acute toxicity is recorded at levels up to the water solubility, and which are not rapidly degradable and have a log Kow ≥4, indicating a potential to bioaccumulate, will be classified in this category unless other scientific evidence exists showing classification to be unnecessary. Such evidence would include an experimentally determined BCF < 500, or a chronic toxicity NOEC > 1 mg/l, or evidence of rapid degradation in the environment."