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Short-term toxicity to fish

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Description of key information

96 h-LC50>0.1 mg/L, < 1 mg/L (OECD guideline 203, non-GLP, RL2), read across from Stearic acid 3-(dimethylaminopropyl)amide

Key value for chemical safety assessment

LC50 for freshwater fish:
0.1 mg/L

Additional information

No experimental data are available for C16-18 DMAPA amidoamine. However, an acute toxicity study according to OECD guideline 203 with the read-across substance Stearic acid 3-(dimethylaminopropyl)amide is available. For justification for read-across see endpoint summary "Aquatic toxicity".

In an acute fish test with rainbow trout no mortality was observed at the limit test concentration of 0.1 mg/L. In a range finding test also at 0.1 mg/L no mortality was observed but at 1 mg/L 100% mortality occurred. This means the LC50 (96h) is in the range of 0.1 and 1 mg/L. This result is regarded as sufficient as a chronic fish test result with a NOEC of 0.1 mg/L is available (see IUCLID Chapter 6.1.2).

 

The following study showing similar results with C20/22 ATQ is enclosed to justify the read-across approach for sediment and terrestrial toxicity studies:

 

The acute toxicity of the test item C20/22 ATQ to fish (zebrafish) was determined according to OECD-Guideline for Testing of Chemicals No. 203 (1992). A semi-static test with the nominal concentrations of 1 - 1.78 - 3.16 - 5.62 - 10 mg/L corresponding to the geometric mean measured concentrations of 0.651 – 1.11 – 2.57 – 4.70 – 8.22 mg/L and a renewal of the test media after 48 h was performed. Duration of the test was 96 h. 7 test organisms were exposed to each concentration and control. Water quality parameters pH-value, temperature and oxygen-saturation measured after 0, 24, 48, 72 and 96 h were determined to be within the acceptable limits.

The concentration of the test item and control were analytically verified via LC-MS/MS from freshly prepared media after 0 and 48 h and from 48 h old media after 48 and 96 h.

The test item has a low water solubility and sorbs to organic and 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 organism and walls of the test vessel) 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. Due to the short exposure period these low recoveries cannot be associated to biodegradation. This means the test substance is present in the test system and therefore available for exposure (dissolved in water and sorbed also called bulk). This so called Bulk Approach is described by ECETOC (2003). Due to the properties of the test item geometric mean measured concentrations have to be used. The 96 h LC50 was 3.5 mg/L (95 % c.i. 2.57 - 4.70 mg/L).