Pitch, coal tar, high-temp.

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0 mg/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:

0.84 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.366 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

Assessment factor:

50

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

0.28 mg/kg food

Assessment factor:

30

Additional information

Pitch, coal tar, high temp. is a 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. 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 7.5 %. Maximum concentration of benzo[a]pyrene is 1.5 % (see CSR Sect. 1.).

Due to its poor solubility in water, tests for aquatic toxicity were performed using water-accommodated fractions. Pitch, coal tar, high temp. did not produce noticeable acute aquatic toxicity under standard test conditions in fish, daphnia, and algae at nominal concentrations of 100 mg/L (loadings). In addition, significant chronic toxicity was not observed at nominal concentrations (loadings) of 100 mg/L in a Daphnia reproduction test (see CSR Sect. 7.1.).

Based on these results, pitch, coal tar, high temp., is not considered to be an environmentally hazardous substance due to its inert inherent properties. Because of its poor water-solubility and its complex high-molecular aromatic structure, it can be neither biodegraded nor bioaccumulated. Coal tar pitch failed to show acute and chronic aquatic toxicity.

Nevertheless, EPA PAH can exert adverse effects to the environment. They are present in coal tar pitch, high temp. and may be released into the environment from emissions of coal tar pitch to a certain extent during manufacture and use. In the absence of significant aquatic toxicity of coal tar pitch, they will be used as surrogate to assess a possible impact of coal tar pitch on environmental protection targets.

Phototoxic effects produced by certain PAHs under the influence of sun/UV-light can be waived by way of a weight-of-evidence approach, namely by comparing water solubility and photo-toxicity data of critical key components of pitch.

For environmental assessment, it is assumed that the basic composition of the substance is maintained during release. Environmentally active components are benzo[a]pyrene and other PAH (1.5 % and 7.5 % maximal concentration, respectively). The highly condensed, inert matrix of coal tar pitch is neither soluble nor biodegradable or bioaccumulating. This material will not contribute to the environmental hazard of coal tar pitch. The inclusion of total EPA PAH in coal tar pitch in the environmental assessment will adequately characterise the environmental hazard associated with coal tar pitch, high temp. Risk will very likely be overestimated by this approach.

For the purpose of risk assessment, benzo[a]pyrene is selected as marker substance, since it is present in coal tar pitch at the highest concentration of the EPA PAH. In addition, it is one of the best characterised PAH components and one of the most environmentally toxic PAH.

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

In a second step, PNECs for benzo[a]pyrene are extrapolated to PNECs valid for total coal tar pitch, high temp. In a simplified approach, a similar average environmental toxicity is supposed for benzo[a]pyrene and the other EPA PAH present in coal tar pitch. In order to account for the presence of the other EPA PAH in coal tar pitch, linear extrapolation is performed based on the concentrations of benzo[a]pyrene and total EPA PAH in coal tar pitch (1.5 % and 7.5 %, respectively). Thus, benzo[a]pyrene specific PNECs are reduced by a factor of 1/5 (1.5 divided by 7.5) to obtain PNECs representing total coal tar pitch, high temp.

The resulting PNECs for pitch, coal tar, high temp., are displayed in the table above. These PNECs will be used in the exposure assessment and risk characterisation in CSR Sect. 9 and 10.

Conclusion on classification

Because pitch, coal tar, high temp. (CTPht) 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 CTPht. The classification criteria are applied to the loading rate.

Pitch, coal tar, high temp., produced no acute aquatic toxicity under standard test conditions in fish (OECD TG 203), in daphnia (OECD TG 202), and in algae (OECD TG 201). The effective loadings, EL50/LL50 values, were consistently higher than 100 mg/L. Based on weight of evidence, there is no concern over PAH-induced acute photo-toxicity. Furthermore, CTPht has no bioaccumulation potential.

Hence, based on experimental evidence and weight of evidence, pitch, coal tar, high temp. requires no classification for environmental hazards in accordance to Regulation (EC) 1272/2008 (CLP regulation) amended/consolidated version of 01.01.2020, Annex I, section 4.1.2.6., Tables 4.1.0 (a) and 4.1.0 (b) (iii) (compare to Annex VI, Table 3 of Regulation (EC) No. 1272/2008 amended by Commission Delegated Regulation (EU) 2020/217 of 4 October 2019).

However, for precautionary reasons, CTPht is recommended to be classified for long-term aspects as a potential source of environmental release of PAHs, which may be a cause of concern. Therefore, CTPht is self-classified by the registrant based on the ‘Safety net‘ classification as Aquatic Chronic 4 (H413: May cause long lasting harmful effects to aquatic life) according to Annex I, section 4.1.2.6., Table 4.1.0.(b) (iii) of Regulation (EC) 1272/2008 (current version).