Registration Dossier

Environmental fate & pathways

Bioaccumulation: aquatic / sediment

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Justification for type of information:
The substance falls within the applicability domain of the selected (Q)SAR method.
Qualifier:
no guideline available
Key result
Value:
3.162 L/kg
Conclusions:
Predicted BCF of 3.162 L/kg wet-wt
Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail
Justification for type of information:
The study with the read across substance is considered sufficient to fulfil the information requirements.
Reason / purpose:
read-across source
Principles of method if other than guideline:
The study was conducted according to the methods described by Branson DR, Blau GE, Alexander HC, and Neely WB (1975). Transactions of the American Fisheries Society, Vol. 104, No. 4: 785-792
GLP compliance:
no
Radiolabelling:
yes
Test organisms (species):
Lepomis macrochirus
Details on test organisms:
Juvenile bluegill, Lepomis macrochirus, having an average wet weight of 0.49 g and a standard length ranging from 3.0 to 5.1 cm, were obtained from a commercial hatchery and maintained under laboratory conditions for a minimum of 2 weeks prior to testing. The fish were held in continuously flowing, carbon-filtered well water having a total hardness of 120 mg/litre (as calcium carbonate). The fish were fed frozen brine shrimp twice daily. This was occasionally supplemented with feedings of live Daphnia. A 12-h photoperiod was maintained in the holding facilities.
Route of exposure:
aqueous
Test type:
flow-through
Water / sediment media type:
natural water: freshwater
Total exposure / uptake duration:
28 d
Hardness:
total hardness of 120 mg/litre (as calcium carbonate)
Test temperature:
21 °C
pH:
7.4
Dissolved oxygen:
near saturation
Details on test conditions:
The bioconcentration test system was based on that described by Branson et al..
The test chambers were 37-litre, all-glass aquaria fitted with removable glass covers.
A standpipe was used to maintain the water volume in the aquaria at 30 litres.
The tank effluents were collected in a common drain and filtered through activated carbon prior to their disposal.
A combination of incandescent and fluorescent lighting was controlled by an automatic timer to provide a 12 h photoperiod simulating dusk and dawn with graduating intensities.
The system provided a daylight intensity of approximately 350-550 cd (200-300 footcandles).
A 1 L proportional diluter was modified to deliver two concentrations of the test material.
A peristaltic pump or a multichannel syringe pump was used to meter the stock solutions directly into the diluter mixing chambers.
The entire diluter assembly was contained within a stainless steel housing to minimize the possibility of 14C contamination. All tests were conducted at 21 ± 2°C in carbon-filtered well water.
A flow rate of 10 litres/h, with a 95 percent replacement time of approximately 9 h, was sufficient to maintain the dissolved oxygen levels at greater than 60 percent of saturation.
Nominal and measured concentrations:
0.76 and 0.08 mg/L
Type:
BCF
Value:
ca. 1.8
Basis:
whole body w.w.
Time of plateau:
28 d
Calculation basis:
steady state
Remarks on result:
other: Conc.in environment / dose:0.08 mg/L
Type:
BCF
Value:
ca. 1.1
Basis:
whole body w.w.
Time of plateau:
28 d
Calculation basis:
steady state
Remarks on result:
other: Conc.in environment / dose:0.76 mg/L
Elimination:
yes
RS-Freetext:
The measured concentrations of the test compound averaged approximately 80 percent of the nominal values.
There was no substantial difference in measured concentrations during the kinetic (Cwk) and the plateau (Cwp) exposures; the coefficient of variation was less than 10 percent in all cases.

28-Day (Plateau) Method
-----------------------
At exposures of 0.76 and 0.08 mg/litre, 14C-EDTA exhibited an extremely low bioconcentration potential. Not until 672 h of continuous exposure did the EDTA concentrations in fish exceed those in the water. The plateau BCF values for EDTA were approximately 1.1 at 0.76 mg/l and 1.8 at 0.08 mg/l, respectively and were independent of the exposure concentration for the range of values tested.
After the transfer to clean water, there was an apparent difference between the two exposure levels in the rate of elimination of 14C activity.
For fish exposed to 0.76 mg/litre, approximately 81 percent of the accumulated 14C residues were eliminated within 336 h, for fish exposed to 0.08 mg/litre, only 60 percent of the accumulated 14C residues had been eliminated within a comparable time.

5-Day (Kinetic) Method
----------------------
The rate constants calculated for 14C-EDTA were independent of the exposure concentrations, although the higher-level exposure may have been clearing somewhat faster. The projected equilibrium BCF values were similar to those observed in the plateau test and, again, serve to emphasize the extremely low bioconcentration potential of EDTA.

Description of key information

Key value for chemical safety assessment

BCF (aquatic species):
3.2 L/kg ww

Additional information

Estimation using a valid quantitative structure activity model for HEDTA predicts a BCF of 3.162. This estimation is supported by experimentally derived BCF data of 1-2 on a structural analogue of the substance, tetrasodium EDTA.

It is considered unlikely that HEDTA will bioaccumulate.