Ammonium dodecylbenzenesulphonate

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Justification for type of information:

Peer reviewed publication

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 E (Bioaccumulation: Flow-through Fish Test)

GLP compliance:

not specified

Radiolabelling:

not specified

Details on sampling:

Water samples (~40 ml) were taken at least once per day, and extracted immediately or preserved with 10% vol MeOH and stored under N2 in a refrigerator for no more than 2 days. Fish samples were killed by immersion in liquid N2, and stored at -20 degrees C until analysis. 2-4 replicates of fish samples were taken.

Vehicle:

not specified

Details on preparation of test solutions, spiked fish food or sediment:

To address differences in composition of mixtures, bioconcentration potential was calculated for
1) mixtures typical of LAS in European detergent formulations (C10 12%, C11 29%, C12 34%, C13 24%; average alkyl chain length = C11.6) and
2) mixtures typical of LAS in filtered Mississippi river water (C10 45%, C11 23%, C12 23%, C13 2%; average chain length = C10.8).

Stock solutions were kept under N2 to prevent aerobic biodegradation.

Test organisms (species):

Pimephales promelas

Details on test organisms:

TEST ORGANISM
- Common name: fathead minnow
- Source: Urecht University hatchery
- Weight at study initiation (mean and range, SD): 0.5-1 g
- Health status: free from observable diseases and abnormalities
- Feeding during test
- Amount: 1 % body weight per day, in order to minimize suspended solids, fish were fed for 30 min in a separate aquarium

ACCLIMATION
- Acclimation period: 1 week

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

192 h

Hardness:

1.21 mM

Test temperature:

20.7-22.5 degrees C

Details on test conditions:

When tested by itself: The exposure phase in Experiment A was 48-hours. The exposure phase in Experiments B-D ranged from 168 to 192 hours. Due to the rapid equilibrium demonstrated in these studies, a longer exposure period was not needed. Fish were then transferred to untreated water for the depuration phase (duration not stated).

TEST SYSTEM
- Test vessel: aquaria
- Type of flow-through (e.g. peristaltic or proportional diluter): peristaltic
- Renewal rate of test solution (frequency/flow rate): 1 L/day g fish


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted H2O

Nominal and measured concentrations:

2.7 and 4.1 uM

Reference substance (positive control):

not specified

Details on estimation of bioconcentration:

The calculation of BCF for the typical mixtures was done using the following equation developed in the above testing:

(ΣCf,i/ΣCw,i)rel = Σ(Φi,w ∙ BCFi,rel)

Remarks on result:

other: not reported

Remarks on result:

other: Data not fully reported.

Details on results:

The BCFs were 87 L/kg for a standard mixture typical of LAS in European detergent formulations (average alkyl chain length = C11.6) and 22 L/kg for a representative environmental sample (filtered Mississippi river water, average alkyl chain length = C10.8)

When tested by itself:

Values of Steady-State Bioconcentration Factor (BCF_ss) and Average Length of Alkyl Chain (n_C,Av) are shown in the following table.

                                                

expt	comp*	BCFss L/kg	nC,Av
A	C10-2	1.7	10.8
	C11-2	5.8
	C12-2	47.6
	C13-2	353.8
B	C11-5	6.1	11.7
	C12-2	99.1
	C12-5	10.0
	C13-5	34.0
C	C11-5	9.8	11.4
	C12-2	168.4
	C12-3	42.1
	C12-6	31.9
D	C10-2	6.0	10.6
	C11-2	31.9
	C12-2	211.5
	C13-2	987.2
	C10-in	3.0
	C11-in	9.1
	C12-in	29.9
	C13-in	112.4

*In the format C_n-m, n and m are the length of the alkyl chain and the position at which the sulfophenyl moiety is substituted to the alkyl chain, respectively.

As shown in the table, BCF values ranged between 2-1000 L/kg.  Experiments A, B and D showed that BCFs increase with increasing alkyl chain length for a given isomer.  In addition, the results of Experiments B and C demonstrate that the closer the p-sulfophenyl moiety is positioned to the terminal carbon of the alkyl chain, the higher the BCF.  However, alkyl chain length has a much bigger effect than does the phenyl position.

Validity criteria fulfilled:

yes

Conclusions:

BCF values ranged from between 2 and 1000 L/kg, with BCFs increasing with increasing alkyl chain lengths.

Executive summary:

The bioaccumulation potential of a series of LAS substances was evaluated in flow-through studies with fathead minnows. Results show that the bioconcentration potential of LAS is low and is decreased by environmental processes such as biodegradation and absorption, which reduce aquatic concentrations.

Description of key information

The experimentally determined BCF of LAS-Na is 2 - 1000 L/kg (depending on alkyl chain length); estimated BCF for IPA is < 10.

The test does not need to be conducted as the substance is readily biodegradable, but data on similar substances are available.

Key value for chemical safety assessment

BCF (aquatic species):

500 L/kg ww

Additional information

No bioaccumulation study is available for LAS-IPA. The endpoint of bioaccumulation was addressed with data for LAS-Na and IPA (see read-across statement).

The experimentally determined BCF of LAS-Na is 2 - 1000 L/kg (depending on alkyl chain length); estimated BCF for IPA is < 10. In the bioaccumulation study with LAS-Na it was shown that BCFs increased with the length of the alkyl chain for C10 to C13.The BCF of LAS-IPA will be well below 1000 L/kg, since the C-chain length of the constituents of LAS-IPA is more or less equally distributed over the C10, C11, C12 and C13 constituents, with the C11 and C12 components most abundant. Additonally it was shown in the article by Tolls et al. (1997) that the BCF decreases with the p-sulfophenyl moiety being positioned further away from the terminal carbon of the alkyl chain, which supports a lower BCF of LAS-IPA as well, based on its composition with the p-sulfophenyl moiety on the C4 position mainly. In fact, only for C13-LAS with the p-sulfophenyl moiety positioned at the C2 position a BCF higher than 500 L/kg was observed, so the BCF for LAS-IPA will be below 500 L/kg..

It can be concluded that the bioconcentration potential of LAS-IPA is low.