Lead sulfochromate yellow

Bioaccumulation: aquatic / sediment

Description of key information

The median BCF fish for LEAD in the database of the vRAR was 23 L/kg whereas the median BCF mussel of the remaining studies was 675 L/kg.
The 50th percentile for a mixed diet was calculated as 1553 L/kg. The latter value was considered more environmentally realistic. 

Key value for chemical safety assessment

BCF (aquatic species):

1 553 L/kg ww

Additional information

A small proportion of the parent substance C.I. Pigment Red 104 or C.I. Pigment Yellow 34 may dissolve and release chromate ions (CrO₄^2-) and lead ions (Pb²⁺).

The IUCLID data set includes results from a literature search on the bioaccumulation of both chromium and lead. Both moieties of the pigments may accumulate in organisms (Tulasi et al. 1992, Avenant-Oldewage and Marx 2000). For lead a concentration factor of 360 was detected in Poecilia reticulata after 28 days of exposure to 50 µg lead/l (Vighi, 1981). Generally biomagnification of lead is not expected. Similarly the BCF in the crab Potamonautes perlatus was circa 500 L/kg after exposure to 30-40 µg lead/l. The bioconcentration factor for the sediment was 3.5 (dimensionless, Reinecke et al., 2003).

For chromium (VI) a BCF of 1 l/kg was determined (Fromm and Stokes 1962). However, CrO₄^2- ions will be reduced to less reactive chromium (III) ions under most environmental conditions. Chromium (III) is less bioavailable and therefore chromium (III) is expected to be less bioaccumulative. In general the bioaccumulation of both metal ions increases with rising temperature, alkalinity and lower water salinity.

Both lead and chromium have been discussed extensively under the EU-Existing Chemicals Regulation and the results were reported in a Risk Assessment Report (RAR 2005) for Chromium and the voluntary RAR for Lead (2008).

The bioconcentration factor for lead from the vRAR (2008) and the bioconcentration factors for chromium (VI) and chromium (III) proposed in the EU RAR (2005) are presented in the table:

Substance	Species		Remarks
Chromium (VI)	Fish	1 L/kg	Used to estimate concentration of chromium (VI) in fish based food chain
	Mussels	1820 L/kg	Based on measured values in marine species
Chromium (III)	Fish	100 L/kg	Used to estimate concentration of chromium (III) in fish resulting from uptake and subsequent reduction in biota of chromium (VI)
	Mussels	560 L/kg	Based on measured values in marine species
Lead	Fish	23 L/kg	50th percentile of range in BCFfish
	Mollusc diet	675 L/kg	50th percentile of range in BCFmolluscs
	Mixed diet	1553 L/kg	50th percentile of range in BCFmixed food diet

Chromium:

The BCF values for chromium VI and III were derived from values measured in a variety of systems. The available data indicated that the BCF for chromium (VI) in fish was low (around 1 L/kg). However, it was noticed that chromium (VI) appears to be reduced to chromium (III) once it has been taken up in the organisms. Therefore a BCF of 100 was estimated from the total chromium concentration in biota / chromium (VI) concentration in water. Direct uptake of chromium (III) from the water phase was not assumed because of the low water solubility and strong sorption of chromium (III) to sediment under most environmental conditions.

It should be noted however that secondary poisoning for chromium (III) is not assessed in the risk characterisation (and hence the BCF for chromium (III) has not been used).

The uptake of chromium by aquatic species may be pH dependent, but it was concluded in the EU RAR that there was not sufficient information available to take this into account for the BCF.

Lead:

The BCF values for lead were derived from field studies taking into account all exposure routes as this was considered to be more environmentally realistic. BCF of lead in fish and invertebrates were dependent on the exposure concentration in water because of the active regulation of internal Pb body concentrations in the organisms. Therefore only BCF of studies with realistic dissolved Pb concentrations (between 0.18 and 15 µg/L) were selected for the BCF evaluation.

The median BCF fish of the resulting database was 23 L/kg whereas the median BCF mussel of the remaining studies was 675 L/kg.

The 50th percentile for a mixed diet was calculated as 1553 L/kg.This value was used for the calculation of PECoral in the mussel-based food chain in the vRAR as it was considered to be more environmentally realistic. 

It should be noted that the risk characterisation for secondary poisoning of lead was not included in the vRAR because there was no agreement on the PNECoral to be used.