Dibutyl phthalate

Toxicity to aquatic algae and cyanobacteria

Description of key information

Maziars, T.P., 1984, studied the phytotoxicity of 14 phthalate esters (including dibutyl phthtalate) to the freshwater green alga Selenastrum capricornutum under static conditions in the laboratory.The 10-day EC50 for phthalate IC (dibutyl phthalate) based on cell numbers was 0.75 mg/L with 95% confidence limits of 0.58 - 0.99 mg/L. 10d NOEC based on cell numbers was 0.39 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:

0.75 mg/L

EC10 or NOEC for freshwater algae:

0.39 mg/L

Additional information

In the European Union Risk Assessment Report for dibutyl phthalate, 2004 (EUR 19840 EN)are presented also other toxicity results for algae and cyanobacteria (see table below). The lowest observed 50% effect concentration for freshwater species was established by According to EU Risk Assessment Report, 2004 the test with the marine dinoflagellate Gymnodium breves howed a very poor reproducibility. In the first assay an EC50 of 0.0034 mg/L was established, whereas in the second, a value of 0.2 mg/L was found.

Method	Results (95% C.I.)  (mg/L)	Remarks	Reference
92/69/EEC	1.2(72 h EC50)	–    Desmodesmus subspicatus	Hüls (1995)
DIN 38412/9	3.5(48 h EC50; biomass)	–    Desmodesmus subspicatus	Kühn and Pattard (1990)
DIN 38412/9	9.0(48 h EC50; growth rate)	–    Desmodesmus subspicatus	Kühn and Pattard (1990)
Other	0.0034 - 0.2(96 h EC50)	–    Gymnodium breve	Wilson et al. (1978)

The NOEC values from EU Risk Assessment Report for DBP, 2004 for both freshwater and marine algae are presented in table below.

According toEU Risk Assessment Report for DBP, 2004 is

necessary to discuss the 14-day LOEC of 0.002 mg/L for the blue-green algae Synecchococcus lividusin more detail and however, the ecological significance of this effect is unknown and therefore the value was not used for the PNEC derivation.

Method	Results NOEC(95% C.I.) (mg/L)	Remarks	Reference
Other	2.8(7 d)	–    Selenastrum capricornutum	Melin and Egnéus (1983)
EGG-CMA-002	0.8(10 d)	–    Selenastrum capricornutum	CMA (1984)
Other	0.6-0.7(? d)	–    Skeletenoma costatum –    marine	Medlin (1980)
Other	0.2(8 d)	–    Dunaliella parva –    marine	Acey et al. (1987)
Other	2.0(4 d)	–    Thalassiosira pseudomona –    marine	Acey et al. (1987)
Other	0.002(14 d LOEC)	–    Synecchococcus lividus –    marine	Acey et al. (1987)