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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Bioaccumation testing on three different aquatic species (fish, oysters and mussels) are reported.  
Based on the measured BCF data for TEL, high bioaccumulation potential cannot be excluded. However, this substance hydrolyses quickly in water so the assessment of the bioaccumulation potential of the degradation products is considered most relevant. The first hydrolysis products are expected to be triethyllead salts which have experimental BCFs of 88-460 dependent on aquatic species. Triethyllead salt also has a log Kow of -1.76, indicating a low potential for bioaccumulation. This substance is further degraded to di-and monoethyllead and it can be expected that these hydrolysis products also have low bioaccumulation potential
The BCF value quoted is the highest for fish exposed to 0.2 mg/l for 41 days (to steady state) with a depuration time of 56 days

Key value for chemical safety assessment

BCF (aquatic species):
92 dimensionless

Additional information

Bioaccumation testing on three different aquatic species (fish, oysters and mussels) are reported.

No relevant data on bioaccumulation potential of TEL in terrestrial species is available

 

The measured log Kow for TEL is < 5. Measured BCF data are reported in IUCLID 4 (2000) for Crassostrea virginica (18,140) (Heitmuller and Parrish, 1977), Crangon crangon (20) and Oncorhynchusmykiss (92-3,189) (Maddock and Taylor,1980). Most of the BCF values are based on tests with invertebrates (crustaceans and molluscs). It should also be noted that the highest BCF (18,140) for TEL in oysters was recorded from exposure to motor fuel antiknock compound containing 64% TEL and 36% halogenated compounds, which may have affected the accumulation of the TEL component of the mixture. Other marine creatures show much lower BCF factors.

 

Based on the measured BCF data for TEL, high bioaccumulation potential cannot be excluded. However, TEL is unstable in saline waters and undergoes progressive dealkylation eventually forming inorganic lead. The initial dealkylation, which produces a trialkyl lead chloride, is known to proceed rapidly, but the subsequent reactions leading to inorganic lead take place much more slowly. Thus the tetra alkyl leads are unstable in seawater whilst the trialkyl lead chlorides are relatively stable. (Towers and Whittingham, 1979). In the context of accumulation, the tetra alkyl lead compounds are of only minor interest since they have only a transitory existence in seawater. Thus, although some information has been obtained on the short term accumulation of both the tetra and tri alkyl lead materials by measuring the lead content of animals exposed during the acute toxicity study, the major part of this investigation has concentrated on the long term accumulation of the trialkyl lead material, triethyl lead chloride.

 

These first hydrolysis products have experimental BCFs of 88-460 dependent on aquatic species. The Triethyllead salt also has a log Kow of -1.76, indicating a low potential for bioaccumulation. This substance is further degraded to di-and monoethyllead and it can be expected that these hydrolysis products also have low bioaccumulation potential,

The BCF value quoted for the purposes of the CSA is the highest for fish exposed to 0.2 mg/l for 41 days (to steady state) with a depuration time of 56 days (range 88 -92 report). Other BCF values were 300-460 for mussels and 318 -416 for oysters, both had varying exposure times and doses.