Benzene, C15-16-alkyl derivs.

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Study period:

Nov. 1999-March 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study done according to OECD guideline 201.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Benzene, C10-13-alkyl derivs.

EC Number:

267-051-0

EC Name:

Benzene, C10-13-alkyl derivs.

Cas Number:

67774-74-7

IUPAC Name:

undecylbenzene

Constituent 2

Reference substance name:

C10-LAB

IUPAC Name:

C10-LAB

Constituent 3

Reference substance name:

C12-LAB

IUPAC Name:

C12-LAB

Constituent 4

Reference substance name:

C14-LAB

IUPAC Name:

C14-LAB

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Details on test solutions:

Acetone was used as a solvent (1 ml/l).

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Source (laboratory, culture collection): Ecotoxicology Dpt. of Centro Nacional de Sanidad Ambiental. Instituto de Salud Carlos lll 28220 . Majadahonda ( Madrid)

Study design

Total exposure duration:

72 h

Test conditions

Hardness:

(Ca + Mg)

Test temperature:

22 ± 1

pH:

7.1 ± 0.1

Nominal and measured concentrations:

The nominal concentrations tested were 25, 50 and 100 ug/l.
Measured conc. (ug/l) 23, 25, 98

Details on test conditions:

Initial cells density: 10^4
- Determination of cell concentrations: Coulter Counter
Triplicate vessels were used for test solutions and 2-5 for controls.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 50 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

100 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

100 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

No effects were found for LAB C10-C13 at 50 ug/1 (solubility as measured in study for C12 LAB: 37.6 ug/l).
EC50 values were above 100 ug/l for all the tested substances.

Any other information on results incl. tables

TABLE ll
Cell concentrations for LAB CAS 67774-74-7                              Time                 72 hours                              Replicates          3                              Controls             6                              Nº                      10^4 cell/mL                              Threshold           8                              Cell Diameter     3.340 µm                              Cell Volume      19.48  µm^3
Controls
C - 1		C ¿ 2		C ¿ 3		C ¿ 4		C ¿ 5		C - 6
198		207		244		211		208		247
220		210		217		224		210		233
201		205		245		221		230		235
206		207		235		220		216		238
F = 2000                              `x = 220                 S = 13.6                                                                                         N = 4.4 x 10^5                     µ = 1.30
LAB ¿ CAS  67774-74-7
	¬		`x		­	`x	®		`x
	267				281		259				`x = 269
25 ppb	273		278		261	269	268		260		N=5.4x10^5
	294				265		254				µ = 1.33
	288				292		254				`x= 272
50 ppb	277		278		292	288	237		250		`N=5.4x10^5
	268				280		260				µ = 1.33
	230				204		191				`x=216
100 ppb	259		245		206	206	191		198		N=4.3x10^5
	245				209		211				µ = 1.25

TABLE lll
Cell concentrations for LAB C10                              Time                 72 hours                              Replicates         2                              Controls            2                              Nº                     10^4 cell/mL                              Threshold          8                              Cell Diameter    3.340 µm                              Cell Volume      19.48 µm^3
Controls
C-1				C-2
335				356
341				353
375				381
350				363
F = 2000                              x = 357                    S = 9.19                                                                                            N = 7.1 x 10^5                     µ = 1.42
LAB ¿ C10
	¬	`x	­		`x
	212		267			x = 248
25 ppb	222	224	274		272	µ = 1.30
	238		274			N=5x10^5
	282		284			x= 254
50 ppb	229	256	234		252	µ = 1.30
	258		238			N=5.1x10^5
	261		183			x=230
100 ppb	228	245	239		215	µ = 1.27
	248		223			N=4.6x10^5

TABLE IV
Cell concentrations for LAB ¿C12                              Time                168 hours (prolonged)                              Replicates          3                              Controls             5                              Nº                      10^4 cell/mL                              Threshold           8                              Cell Diameter     3.340 µm                              Cell Volume      19.48  µm^3
Controls
C-1		C-2			C-3		C-4			C-5
4033		2469			2251		3241			2551
4168		2499			2115		3309			2619
4347		2469			2243		3392			2661
4182		2479			2203		3314			2610
Annuled           F = 2000                 ` x = 2651                  S = 573.12
N = 5.3x 10^6      µ = 0.89
LAB ¿ C12
	¬		`x	­		`x		®	`x
	2357			2616				3359			x = 2802
25 ppb	2439		2440	2532		2609		3396	3359		N=5.6x10^6
	2525			2679				3322			µ= 0.9
	2378			2119				2235			x= 2313
50 ppb	2510		2432	2210		2223		2320	2285		N=4.6x10^6
	2410			2341				2302			µ= 0.87
	2562			3191				3196			x=2914
100 ppb	2452		2482	3188		3183		3069	3079		N=5.8x10^6
	2432			3172				2973			µ= 0.9

TABLE IV
Cell concentrations for LAB ¿C12                              Time                168 hours (prolonged)                              Replicates          3                              Controls             5                              Nº                      10^4 cell/mL                              Threshold           8                              Cell Diameter     3.340 µm                              Cell Volume      19.48  µm^3
Controls
C-1		C-2			C-3		C-4			C-5
4033		2469			2251		3241			2551
4168		2499			2115		3309			2619
4347		2469			2243		3392			2661
4182		2479			2203		3314			2610
Annuled           F = 2000                 ` x = 2651                  S = 573.12
N = 5.3x 10^6      µ = 0.89
LAB ¿ C12
	¬		`x	­		`x		®	`x
	2357			2616				3359			x = 2802
25 ppb	2439		2440	2532		2609		3396	3359		N=5.6x10^6
	2525			2679				3322			µ= 0.9
	2378			2119				2235			x= 2313
50 ppb	2510		2432	2210		2223		2320	2285		N=4.6x10^6
	2410			2341				2302			µ= 0.87
	2562			3191				3196			x=2914
100 ppb	2452		2482	3188		3183		3069	3079		N=5.8x10^6
	2432			3172				2973			µ= 0.9

TABLE V
Cell concentrations for LAB ¿C14                              Time                72 hours                              Replicates         3-2                              Controls             5                              Nº                      10^4 cell/mL                              Threshold           8                              Cell Diameter     3.340 µm                              Cell Volume      19.48 µm^3
Controls
C-1		C-2			C-3		C-4			C-5
785		620			726		721			739
784		708			669		793			784
716		678			649		786			756
761		668			681		766			760
F = 2000                              x = 727                   S =  48.38                                                                                          N = 1.45 x 10^6                     µ = 1.65
LAB ¿ C14
	¬		x	­		x		®	x
	743			821							x = 779
25 ppb	717		717	859		842					N=1.5x10^6
	692			847							µ= 1.6
	741			750							x= 740
50 ppb	710		728	728		753					N=1.48x10^6
	735			783							µ= 1.6
	705			645				807			x= 719
100 ppb	719		718	611		620		854	819		N=1.4x10^6
	740			604				798			µ= 1.6

TABLE VI
Inhibition of growth rate
Sample : Commercial LAB  CAS Nº 67774-74-7
Concentration ppb	Inhibition %
25	- 2.3
50	- 2.3
100	3.8

TABLA VII
Inhibition of growth rate
Samples:  LAB C10 , LAB-C12 , LAB-C14
Concentration ppb	Inhibition (%)
	LAB ¿C10	LAB ¿C12	LAB ¿C14
25	8.4	-1.1	3.1
50	8.4	2.2	3.1
100	10.5	-1.1	3.1

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72-hr EC50 values were > 100 ug/l for all substances tested. This is higher than the measured solubility limit for C12 LAB of 37.6 ug/L.

Executive summary:

In cases where no data were available on the target substance, Benzene, C15 -16 -alkyl derivs., data were read across from a structurally related material (the test substance).

This study examined the toxicity of linear alkyl benzenes to aquatic algae. Scenedesmus subspicatus was exposed to concentrations of 25, 50 and 100 ug/l of test substance for 72 hrs. During this time, readings of the growth rate were taken. Tests were also done on C10, C12, and C14 linear alkyl benzenes in addition to commercial LAB. The 72 -hr EC50 values for all substances was >100 ug/l, which is higher than the solubility limit for these substances (measured solubility limit for C12 LAB = 37.6 ug/l).