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Short-term toxicity to aquatic invertebrates

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Description of key information

The toxicity of C16-22-(even numbered) alkylamines to Daphnia magna was determined in an OECD 202 GLP study. The EC50 (48h) was established to 1.92 mg/L.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
1.92 mg/L

Additional information

The toxicity of C16 -22 -(even numered) alkylamines to Daphnia magna was determined accordning to an OECD 202 test. The study was conducted under semi-static conditions over a period of 48 h with 5 concentrations of the test item C16-22-(even numbered)-alkylaminesin natural river water ranging from 0.500 to 8.00 mg/L set up in a geometric series with a dilution factor of 2. Twenty daphnids were exposed to each concentration level and the control. The concentrations of the C18- and C22-fraction of the test item C16-22-(evennumbered)-alkylamineswereanalytically verified by LC-MS/MS in the fresh media (0 and 24 h) and in the old media (24 and 48 h) of all concentration levels and the control.

The test item C16-22-(evennumbered)-alkylamineshas a low water solubility and sorbs to organic an inorganic materials by different mechanisms. The sorption processes are mostly non-linear, means are concentration dependent. Due to these properties the test item is difficult to test in synthetic water (e.g. sorption to the test organisms and glass walls of the test vessels) and results from such tests depend from the test settings applied. Using natural river water which contains particulate as well as dissolved organic carbon to which the test item can sorb partially reduces the difficulties encountered in tests with synthetic water (e.g. preventing that the test item settles onto surfaces). The sorbed fraction of the test item is difficult to extract from the test system which normally leads to low analytical recoveries. It was confirmed by measurements that only 6 – 11 % of the test item at a concentration of 2 mg/L nominal sorb to the glassware (see also below). This concentration of 2 mg/L nominal is close to the calculated EC50(48 h). That means that the test item is present in the test system and therefore available for exposure (dissolved in water and sorbed).Due to the properties of the test item the nominal concentrations were used for assessment of the endpoints instead of measured ones.

The recoveries of the C18-fraction were in the range of 38 to 90 % of the nominal values in the fresh media (0 and 24 h) and 2 to 60 % in the old media (24 and 48 h). Recoveries of the C22-fraction were in the range of 68 to 100 % of the nominal values in the fresh media (0 and 24 h) and 2 to 74 % in the old media (24 and 48 h).

The water quality parameters (pH-value and dissolved oxygen concentration), measured at 0, 24 and 48 h, were determined to be within the acceptable limits. The validity criteria of the test guideline were fulfilled.

EC10-, EC50- (with Confidence Interval), EC100- Values, NOEC and LOEC

                  (based on the nominal test item concentrations ofC16-22-(evennumbered)-alkylamines)

Endpoints

(with 95 % confidence limits)

Test

Duration

[h]

C16-22-(even numbered)-alkylamines

Nominal Concentration of the Test Item

[mg/L]

EC10

24

  2.84  (CI: – 3.45)

48

  1.72  (CI: 1.68 – 1.75)

EC50

24

  6.42   (CI: 5.83 – 6.88)

48

  1.92  (CI: 1.89 – 1.94)

EC100

24

> 8.00

48

  4.00

NOEC

48

  1.00

LOEC

48

  2.00