Quaternary ammonium compounds, bis(hydrogenated tallow alkyl)dimethyl, acetates

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Study period:

1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Results published in a peer-reviewed scientific publication and in the EU Risk Assessment DODMAC (EU, 2002).

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 305 (Bioconcentration: Flow-through Fish Test)

Radiolabelling:

yes

Vehicle:

no

Test organisms (species):

Lepomis macrochirus

Details on test organisms:

Bluegill, Lepomis macrochirus, were obtained from commercial fish hatcheries and averaged 1.3 g in weight (from 1.2 to 1.7 g) and 38 mm in length (from 23 to 60 mm). Fish were acclimated for 14 to 30 d prior to use in water having physical and chemical characteristics similar to those of the water used in the tests. Fish were fed trout chow daily during acclimation and during tesing, but were not fed 24 to 48 h prior to testing.

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

49 d

Total depuration duration:

> 21 - < 35 d

Hardness:

14-38 mg/L CaCO3 (Town river)
315-348 mg/L CaCO3 (Well water)

pH:

6.4-7.7 (Town river)
7.1-7.9 (Well water)

TOC:

TOC: no data
Suspended matter: Town river 2-84 mg/L, Well water 0 mg/L

Details on test conditions:

Bluegill were exposed to nominal 20 µg/L concentrations of 14C-labeled DTDMAC in aerated, carbon-filtered well water and to 23 µg/L in Town River water under continuous flow conditions. No solvent was used in the two tests. The 14C-DTDMAC equilibrated in the test waters for 13 d prior to introducing the fish into the 30-liter glass test chambers. The 115 fish in the two exposure aquaria and the 50 fish in the two control tanks were fed trout chow daily during testing.

Nominal and measured concentrations:

Nominal concentration tested = 20 µg/L

Type:

BCF

Value:

256 L/kg

Basis:

non-edible fraction

Time of plateau:

14 d

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:20 µg/L - Well water

Type:

BCF

Value:

94 L/kg

Basis:

non-edible fraction

Time of plateau:

49 d

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:23 µg/L - River water

Type:

BCF

Value:

32 L/kg

Basis:

whole body w.w.

Time of plateau:

14 d

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:20 µg/L - Well water

Type:

BCF

Value:

13 L/kg

Basis:

whole body w.w.

Time of plateau:

49 d

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:23 µg/L - River water

Elimination:

yes

Parameter:

other: 93% of the test item was depurated after 14d

Depuration time (DT):

14 d

Bioconcentration of DTDMAC by bluegill varied with the tissue analyzed and with the dilution water used in the test. Bluegill exposed to a mean-measured concentration of 20 (±

1 SD = 10) µg/L DTDMAC in well water and to an average 23 (k 12) µg/L DTDMAC in Town River water did not concentrate the surfactant in edible tissue (fillets) to any significant degree. On the other hand, residues were measured in inedible tissue (viscera) of fish in both test waters.

Mean BCF in inedible tissues of fish in well water and river water were 256 and 94, respectively. These BCF values were based on

the ratio of the mean¹⁴C residues in fish to the mean-measured concentrations in the waters over days 14 to 49 of the exposure period (time of steady state). During this time period, the residues averaged 4,100 (well water) and 1,700 (river water) µg/kg, and the mean DTDMAC levels in the well and river waters were 16 and 18 µg/L, respectively. Bluegill, after being transferred to well water containing no DTDMAC, eliminated 93% of the residues in inedible tissues after 14 d.

Whole body BCF were estimated to be 32 (well water) and 13 (river water). Based on estimated residues in whole body and in inedible tissues, bluegill concentrated DTDMAC in well water about three times more than in river water.

Conclusions:

The BCF values for bluegill were very low in river water (13 L/kg wwt), and slightly higher in well water (32 L/kg wwt). The BCF river water of 13 L/kg wwt was used in the EU Risk Assessment DODMAC (EU, 2002). The relatively higher values in well water, whether based on residues in inedible tissue or in whole body, indicate the reduced bioavailability of the surfactants in surface water.

Executive summary:

Lepomis macrochiruswas exposed to¹⁴C-DTDMAC for 49 days in a continuous flow-through system in river water and laboratory water with mean concentrations in the test period of 18 µg/L and 16 µg/L respectively (no solvent carrier, Lewis & Wee, 1983). The river water was sampled at Town River, Massachusetts, and contained 2-84 mg/L suspended solids, 0.04-0.59 mg/L (methylene blue active substances) MBAS and 10-15 mg/l disulfine blue active substances (DBAS) (pH = 6.4-7.7; total hardness = 14-38 mg/L CaCO₃). In river water,BCFs of 13 L/kg in the whole bodyand 94 in the inedible tissue (viscera) were estimated based on measured concentrations. When laboratory water was used, the respective BCFs were 32 and 256 L/kg. In both waters DTDMAC did not concentrate to a significant degree in edible tissue (BCF of the fillets < 5 L/kg). In a depuration phase in well water 93% of the accumulated radioactivity was eliminated from the inedible tissues after 14 days.

Overall, these results demonstrated that testing cationic surfactants under more realistic conditions (in river water) give lower bioavailibility compared to studies using laboratory water.

Based on these test data, it can be concluded thta DTDMAC is not bioconcentrating in fish.

Key value for chemical safety assessment

BCF (aquatic species):

13 L/kg ww