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Due to the complex composition of anthracene oil < 50 ppm BaP, a single BCF value cannot be determined for the substance. Relevant components (all PAH) will have their individual BCF values. Phenanthrene is main constituent (ca. 30%) and will best represent the bioaccumulation properties of anthracene oil. Hence, this substance is selected as marker substance (see Chapter 4.).

BIOCONCENTRATION in fish focused on PHENANTHRENE as marker substance

In both, the risk assessment report on coal-tar pitch (EU 2008) and the expertise for CONCAWE (Lampi and Parkerton 2009), the study by Jonsson et al. (2004) received the highest rate of reliability. Therefore, this work is given highest priority.

In this obviously well-performed bioconcentration study similar/according to OECD 305 (flow-through), BCF values for phenanthrene ranged from 700 to 2229, depending on the exposure level (low or high) and the calculation method applied (kinetic method or steady state). At the low exposure level (0.12 µg/L), less test substance accumulated in the tissue due to a lower uptake rate than at the high level (1.12 µg/L), while the very high excretion/depuration rates were the same at either exposure condition. Lower BCF values resulted when calculating the BCFs using the ratios of tissue vs. water concentration at steady state rather than the ratio of uptake vs. elimination. Thus, the high-level BCF based on the steady state method fell below 2000 (BCF = 1623).

In their expertise, Lampi and Parkerton (2009) re-calculated the kinetics-based BCF values by accounting for the high lipid content of the fish (approx. 10 %). Normalised by this way down to the standard lipid level of 5 % in fish, the adjusted BCFs arrived at 417 and 1149, respectively.

This study provides evidence that phenanthrene has a low to moderate bioconcentration potential. However, the extent of bioconcentration is mainly determined by the metabolic and excretory capacity of the target organism.

Lampi and Parkerton state that - "with the exception of phenanthrene - reliable fish BCF data indicate that the EPA PAH show BCFs below 2000" (note: Anthracene had been excluded from their treatise). They continue: "In the case of phenanthrene, there are two high quality BCF values, both below 2000 and several values that are judged to be reliable with restrictions that fall between 2000 to 5000. Thus, a weight of evidence approach for phenanthrene would suggest it fulfils the B criterion, if based only on bioconcentration data.

Taking into account the complimentary information for assessing bioaccumulation properties along the food chain, available data clearly demonstrate that all PAHs investigated, including phenanthrene, exhibit a low biomagnification potential (WHO 2003; EU 2008; Lampi and Parkerton 2009).

Conclusion according to WHO:

"Aquatic organisms that metabolize PAHs to little or no extent, such as algae, molluscs and the more primitive invertebrates (protozoans, porifers and cnidaria) accumulate high concentrations of PAHs, as would be expected from their log Kow values, whereas organisms that metabolize PAHs to a great extent, such as fish and higher invertebrates, accumulate little or no PAHs.

The concentration of PAHs in vegetation is generally considerably lower than that in soil, the bioaccumulation factors ranging from 0.0001 to 0.33 for BaP and from 0.001 to 0.18 for 17 other PAHs tested.

Biomagnification (the increase in concentration of a substance in animals in successive trophic levels of food chains) of PAHs has not been observed in aquatic systems and would not be expected to occur, because most organisms have a high biotransformation potential for PAHs. Organisms at higher trophic levels in food chains show the highest potential for biotransformation (WHO 1998). " [from Joint WHO 2003, p.147]

References:

EU (2008). Coal-Tar Pitch, high temperature - Risk Assessment. European Union Risk Assessment Report, The Netherlands [http://echa.europa.eu/documents/10162/433ccfe1-f9a5-4420-9dae-bb316f898fe1]

Lampi and Parkerton (2009). Bioaccumulation Assessment of PAHs - Review Paper Prepared for CONCAWE. ExxonMobil Biomedical Sciences, Inc.

WHO (2003). HEALTH RISKS OF PERSISTENT ORGANIC POLLUTANTS FROM LONG-RANGE TRANSBOUNDARY AIR POLLUTION, JOINT WHO/CONVENTION TASK FORCE ON THE HEALTH ASPECTS OF AIR POLLUTION. WHO Regional Office for Europe, World Health Organization 2003