3-(2-dodecenyl)succinic anhydride

Toxicity to aquatic algae and cyanobacteria

Description of key information

The toxicity of the water-accommodated fraction of tetrapropenyl succinic anhydride to the green alga Selenastrum capricornutum (now called Pseudokirchneriella subcapitata) was determined in a GLP-compliant study based on OECD and U.S. EPA guidelines, by read-across based on a grouping of substances (category approach).

Key value for chemical safety assessment

EC50 for freshwater algae:

110 mg/L

EC10 or NOEC for freshwater algae:

33 mg/L

Additional information

The study entitled “Acute Toxicity of the Water Accommodated Fraction (WAF) of OS# 18230U to the Freshwater Alga,Selenastrum capricornutum–Range Finding Test“ (Ward et al., T.R. Wilbury Laboratory, 1997), exposure of freshwater alga to tetrapropenyl succinic anhydride was identified as the key study, by read-across based on a grouping of substances (category approach). The study reported a 96 h median effective concentration (EC₅₀) of 110 mg/L (95% confidence interval = 33 to 330 mg/L) when calculated using cells/ml, and an EC₅₀of 160 mg/L (95% confidence interval = 33 to 330 mg/L) when calculated using average specific growth rate. The 96 h NOEC was determined to be 33 mg/L using both the cells/ml and average specific growth rate. An additional algal toxicity test indicated that the effect of the substance at the highest test concentration of 3,300 mg/L tested was algistatic rather than algicidal.

A category approach is used for the hazard assessment of several endpoints. The hypothesis for the category of C8-12 Alkenyl Succinic Anhydrides is that data can be read-across among members of the category, because the properties and behaviours of category members are similar, based on common functional groups, similar breakdown products, and demonstration of a constant pattern associating the potency of properties with the various carbon chain lengths. Functional groups include a dihydro-2,5-furandione cyclic anhydride ring, a carbon chain of length 8 -12 carbons, and a single carbon-carbon double-bond within the carbon chain. The primary functional group associated with toxicity is the succinic anhydride moiety, which is quickly hydrolysed to form a butanedioic acid. A constant pattern may also be displayed in acute toxicity, dermal irritancy and biodegradation, with the lowest carbon chain length (C8) displaying the highest activity. Irritation, toxicity and degradation potential diminish with increasing carbon chain length. Read-across among the category members is substantiated by the common behaviour in physico-chemical and toxicity behaviours, as provided in the Chemical Category Report Format (CCRF) attached to the IUCLID file. It is adequate to fulfil the information requirements of Annex IX, to be the basis for classification and labelling decisions, and for risk assessment.