Reaction mass of 2-(1,1-dimethylpropyl)anthraquinone and 2-(1,2-dimethylpropyl)anthraquinone

Sediment toxicity

Description of key information

In a 28-day sediment spiked study (according to OECD guideline and GLP principles) with Chironomus riparius, the overall NOEC for emergence rate was 320 mg/kg sediment dw. This value will be used for the CSA.

The toxicity study has been performed with artificial sediment containing 2.1% organic carbon. As the concentration in freshly deposited sediment is taken as the PEClocal for sediment, the properties of suspended matter are used for deriving this PEC. Suspended matter contains 10% organic carbon. Therefore the NOEC from the study needs to be recalculated into a NOEC for a standard sediment, containing an organic carbon content of 10%:

NOEC (to use for the PNEC) = NOEC (from the study) x (10%/2.1%) = 320 x 4.762 = 1524 mg/kg sediment dw.

Then the PNEC derived from this value, can be compared with the PECs calculated in EUSES.

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater sediment:

1 524 mg/kg sediment dw

Additional information

Chironomid larvae (<48 hours old, 20 larvae/replicate, 4 replicates/concentration) were exposed to 2-amylanthraquinone at nominal concentrations of 10, 32, 100, 320 and 1000 mg/kg sediment dw in a sediment spiked system for 28 days. Exposure concentrations in sediment were analytically verified by HPLC-UV at the start of the test (103-113% of nominal) and after 28 days of exposure (78-93% of nominal). 2-Amylanthraquinone concentrations in overlying water and porewater were below the LOQ of 1.0 mg/L throughout the study. Concentrations of 10 until 320 mg/kg had no effect on the number of emerged animals but at a concentration of 1000 mg/kg the emergence was severely reduced. Less than 10 % of the animals emerged during the study at a concentration of 1000 mg/kg. No significant difference in sex ratio was found although the number of males was slightly reduced at concentrations of 320 and 1000 mg/kg. 2-Amylanthraquinone resulted in a delay in the emergence of the chironomids. The development rate was statistically significantly reduced at concentrations of 100, 320 and 1000 mg/kg. The reduction of the development rate at concentrations of 100 and 320 was only 4.0 and 4.9 % (the animals emerged about one day later). Because no effects on emergence rate were found at and below 320 mg/kg while effects on development rate were small (4.0 and 4.9% at 100 and 320 mg/kg), a concentration of 320 mg/kg will be considered as the overall No Oberved Adverse Effect Concentration.