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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Bioaccumulation/bioconcentration factors in freshwater: 1,553 L/kg 

Key value for chemical safety assessment

Additional information

Pyrochlore:

The overall chemical and physiological properties of pyrochlore are principally characterised by a degree of inertness because of the specific synthetic process (calcination at high temperatures, approximately 1000°C), rendering the substance to be of a unique, stable crystalline structure in which the majority of atoms are tightly bound and not prone to dissolution in environmental and physiological media. This has been shown in transformation/dissolution testing for antimony, in which dissolved Sb concentrations were below 27 µg/L (after 7 days at a loading of 0.1g/L) and 2 µg/L (after 28 days at a loading of 1 mg/L); thus implying a solubility of < 0.03% of antimony. Hence, Sb can be considered as not bioavailable and is not regarded concerning toxicological and environmental effects.

On the other hand, lead dissolution levels were much higher (>2.9 mg/L at a loading of 100 mg/L after 7 days at pH 6; 105 µg/L at a loading of 1 mg/L after 28 days at pH 6) and therefore have to be regarded concerning toxicological and environmental aspects. No substance-specific data on the toxicity of pyrochlore are available, so that instead read-across to lead oxide and sparingly soluble lead compounds was conducted

Lead:

Bioconcentration (BCFs) and bioaccumulation factors (BAFs) for Pb from water to aquatic invertebrates and fish weree summarized in the voluntary risk assessment of lead, VRAL (LDAI, 2008)..

Within typical environmental concentration range, the gathered BAFs for fish ranged between 11 and 143 L/kgww(10 – 90th%) with a median value of 23 L/kgwwwhile the BAFs for molluscs ranged between 18 and 3,850 L/kgww(median value of 675 L/kgww), for insects between 968 and 4,740 L/kgww(median value of 1,830 L/kgww) and for crustaceans between 1,583 and 11,260 L/kgww(median value of 3,440 L/kgww)

 

The range of bioaccumulation factor (BAF in L/kgww) of Pb in freshwater organisms.

Diet

Variable

10th%

50th%

90th%

n

Crustaceans

All exposures

1,187

3,159

10,570

8

0.18-15 µg/L

1,583

3,440

11,260

7

Molluscs

All exposures

11

473

3,535

14

0.18-15 µg/L

18

675

3,850

11

Annelids

All exposures

1,620

1,620

1,620

1

 

0.18-15 µg/L

1,620

1,620

1,620

1

Acarides

All exposures

1,730

1,730

1,730

1

 

0.18-15 µg/L

1,730

1,730

1,730

1

Insects

All exposures

968

1,830

4,740

7

0.18-15 µg/L

968

1,830

4,740

7

Fish

All exposures

11

24

245

16

0.18-15 µg/L

11

23

143

16

 

According to the VRAL (2008) a mixed diet scenario is assumed, considering that birds/mammals consume equal proportion of the different food types. Based on significant high bioaccumulation in molluscs, secondary poisoning was also considered for a “mollusc food chain”. The range of bioaccumulation factor (BAF in L/kgww) of Pb in the mixed and mollusc food diet is presented below.

 

The range of bioaccumulation factor (BAF in L/kgww) of Pb in the mixed diet.

Diet

variable

10th%

50th%

90th%

n

Mixed food diet

All exposures

921

1,472

3,740

49

0.18-15 µg/L

988

1,553

3,890

44

Mollusc food diet

All exposures

11

473

3,535

14

0.18-15 µg/L

18

675

3,850

11

 

This table shows that the 50th% of the mixed diet BAF for aquatic organisms is 1,553 L/kg (90th%: 3,890 L/kg) and that the mixed diet scenario is driven by the BAF values retrieved from the invertebrates. The 50th% BAF of the mollusc food diet is somewhat lower, i.e. 675 l/kg (90th%: 3,850 L/kg). The BAF value of 1,553 L/kg is further used for the assessment of the secondary poisoning in the aquatic environment.