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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Bioaccumulation: terrestrial

Currently viewing:

Administrative data

Endpoint:
bioaccumulation: terrestrial
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, and documentation / justification is limited

Data source

Reference
Reference Type:
publication
Title:
BIOACCUMULATION IN THE SOIL TO EARTHWORM SYSTEM
Author:
Des W. CONNELL and Ross D. MARKWELL
Year:
1990
Bibliographic source:
Chemosphere, Vol. 20, Nos. 1-2, pp. 91-100, 1990

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 317 (Bioaccumulation in Terrestrial Oligochaetes)
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Urea
EC Number:
200-315-5
EC Name:
Urea
Cas Number:
57-13-6
Molecular formula:
CH4N2O
IUPAC Name:
urea
Details on test material:
It is assumed that the purity is 100%

Results and discussion

Any other information on results incl. tables

The sources of variation in this study are substantial. Several sources of data from experiments conducted under different conditions are included. Also, it has been demonstrated (Chessels et. al., 1988) that pesticides in soils establish concentration patterns and gradients due to varying environmental conditions, leading to irregular exposure. Despite these limitations, the data are broadly consistent with the transfer of lipophilic compounds through a three phase system involving soil to soil water to organism partitioning, analogous to that observed in oligochaete worms. This is a passive process and is principally dependent on the lipid content of the worms and the organic carbon content of the soil. Transfer from soil to soil water can be described by the same relationships established for sediment to water equilibria. The transfer from soil water to earthworm is described by:

log Kb = log Kow - 0.6

This relationship is consistent with the theoretically derived equation for bioconcentration, which has been found to apply to bioconcentration by aquatic organisms. The bioaccumulation factor derived from the three phase partition theory is in accord with the observed bioaccumulation factor. It demonstrates a weak dependence on the log Kow value and strong dependence on the lipid content of the organism and the organic matter content of the soil.

The Log Kow for urea is -1.73.

Hence the log Kb as calculated with the equation above is -2 .23.

This indicates a low potential for bioaccumulation of urea.

Applicant's summary and conclusion

Conclusions:
Low potential for bioaccumulation.
Executive summary:

The sources of variation in this study are substantial. Several sources of data from experiments conducted under different conditions are included. Also, it has been demonstrated (Chessels et. al., 1988) that pesticides in soils establish concentration patterns and gradients due to varying environmental conditions, leading to irregular exposure. Despite these limitations, the data are broadly consistent with the transfer of lipophilic compounds through a three phase system involving soil to soil water to organism partitioning, analogous to that observed in oligochaete worms. This is a passive process and is principally dependent on the lipid content of the worms and the organic carbon content of the soil. Transfer from soil to soil water can be described by the same relationships established for sediment to water equilibria. The transfer from soil water to earthworm is described by:

log Kb = log Kow - 0.6

This relationship is consistent with the theoretically derived equation for bioconcentration, which has been found to apply to bioconcentration by aquatic organisms. The bioaccumulation factor derived from the three phase partition theory is in accord with the observed bioaccumulation factor. It demonstrates a weak dependence on the log Kow value and strong dependence on the lipid content of the organism and the organic matter content of the soil.

The Log Kow for urea is -1.73.

Hence the log Kb as calculated with the equation above is -2 .23.

This indicates a low potential for bioaccumulation of urea.