Registration Dossier

Administrative data

Endpoint:
biological effects monitoring
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well documented publication which meets basic scientific principles

Data source

Reference
Reference Type:
publication
Title:
Concentrations of rare earth elements in sediments, mussels and fish from a danisch marine environment, Lillebaelt
Author:
Drabaek, I. et al.
Year:
1987
Bibliographic source:
Journal of Radioanalytical and Nuclear Chemistry 114(1): 29-38

Materials and methods

Principles of method if other than guideline:
Results for the content of the rare earth elements (REE), La, Ce, Nd, Sin, Eu, Tb, Yb and Lu in sediments, mussels and fish are presented for an area polluted by REE. The REE are emitted with the process waste water stream from a fertilizer production plant. The method of analysis has been instrumental neutron activation analysis (INAA). An attempt to combine the INAA with a simple destruction/preconcentration method is described.
GLP compliance:
no
Type of study / information:
Results for the content of the rare earth elements (REE), La, Ce, Nd, Sin, Eu, Tb, Yb and Lu in sediments, mussels and fish are presented for an area polluted by REE. The REE are emitted with the process waste water stream from a fertilizer production plant.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): rare earth elements (RRE), sectioned in La, Ce, Nd, Sin, Eu, Tb, Yb and Lu

Results and discussion

Any other information on results incl. tables

In general La, Ce, and Nd account for more than 90% of the total REE content in the discharged process waste water. The concentrations are typically La 43 mg/kg, Ce 70 mg/kg and Nd 20 mg/kg. On a yearly basis the total discharge of REE into the recipient is calculated to 300 - 400 t.

Due to the acidic nature of the process waste water (pH 1 - 2) the REE probably occure in this as ions. REE, however, are very prone to precipitation as hydroxides when discharged into sea water.

At very high dilutions, e.g. 1/2500 - 1/10000, the half-life (time passed until 50% of the tracer had precipitated) was in the order of

hours. The discharge arrangement has carefully been constructed in order to attain such high dilution rates very quickly, and it could therefore be expected that the discharged REE would be dispersed in a relatively large area before sedimentation as hydroxides.

Sediment:

La concentrations in sediment top (0 -2 cm) and bottom (14 -16 cm) samples are in a range of 48.6 and 86.4 mg/kg dry matter and in a range of 23.7 and 31.1 mg/kg dry matter, respectively (4 positions in a distance of approx. 10 - 20 km from the discharge, measurements in two years). The difference between the La-concentrations in the top and the bottom layer indicated the pollution of the top layer.

La concentrations in the sediments of the control area are not shown.

Mussels:

In spite of the relatively high REE-concentrations no differences are found between the mussels (Cyprina islandica) from the polluted sediments and the control mussels from an area with no record of REE pollution. Compared to the REE content in the sediments the REE in the mussels constitute only a few percentages. From laboratory experiments it is known that Cyprina islandica is well capable of accumulating REE when these occur as ions. It therefore seems possible that the relatively low uptake from the sediments, with a high REE content, might be due to the chemical form of the REE in the sediments.

The same effects were observed when the REE concentrations in Mytilus edulis were analysed: no significant differences were found between geographical positions or between shore and buoy mussels.

The authors stated, that although the waste water emitted REE are distributed over a wide area, the bioavailability seems to be very low.

Cyprina islandica: 1.96 - 2.12 mg La/kg dry matter for recipient sediment accumulation area; 2.69 mg La/kg dry matter for control area

Mytilus edulis: 0.73 +/- 0.33 mg La/kg dry matter for different sampling positions over a large geographical area

Fish:

For the analysis of fish (flounder) the detection limits offered by the INAA method have not been sufficient. No results have therefore been produced, even on fish feeded in aquariums with special REE containing feed.

Applicant's summary and conclusion