2,4,6-trimethylpyridine

Endpoint summary

Additional information

Toxicity to aquatic invertebrates

The toxic effect of the test item 2,4,6-Collidine to Daphnia magna was assessed according to OECD Guideline No. 202. For this purpose, young daphnids (< 24 hours old) were exposed in a static test to various concentrations under defined conditions for 48 hours. The recorded effects were the mobility of the daphnids after 24 and 48 hours. This study encompassed 6 treatment groups (5 dose rates of the test item and a control) each containing 20 individuals. The mobility of the daphnids was determined by visual observation after 24 and 48 hours. The test concentrations were 0 (control), 100, 50, 25, 12.5 and 6.3 mg test item/L (spacing factor 2). After 48 hours of exposure no immobilisation of the test animals was observed in the control (validity criteria fulfilled) and up to and including the test item concentration of 50 mg test item/L. At the concentration of 100 mg test item/L 12 animals were immobile. At the concentrations of 25, 50 and 100 mg test item/L some Daphnia were moving slower compared to the control, had agglutinated antennae or were stuck to the water surface. As a conclusion, the 48-hour NOEC was determined to be 50.0 mg test item/L. The 48-hour LOEC was determined to be 100.0 mg test item/L and the 48-hour EC50 value was determined to be 96.5 mg test item/L (nominal values). The initial concentrations and the maintenance of the exposure concentrations during the test were verified in the analytical part. All reported results refer to nominal values since the concentrations of the test item were within ± 20% of the nominal concentrations during the test.

 

 

Toxicity to aquatic algae and cyanobacteria

The purpose of the study was to determine the inhibitory effect of the test item 2,4,6-Collidine on the growth of the freshwater green algae Pseudokirchneriella subcapitata. For this purpose, exponentially growing cultures of this unicellular green algal species were exposed to various concentrations of the test item under defined conditions. The inhibition of growth in relation to control cultures was determined over a test period of 72 hours, and thus over several algal generations. The test method and the test species Pseudokirchneriella subcapitata are recommended by the test. This study encompassed 6 treatment groups (5 dose rates of the test item: 50, 16, 5.0, 1.6 and 0.5 mg test item/L), and a control with three replicates per test concentration and six replicates for the control. At test start 50 mL of the test media were inoculated with nominal 5000 algal cells per mL test medium and defined volumes of the algal suspensions were sampled after 24, 48 and 72 hours for determination of cell densities by spectrophotometric measurement. The cell density on each observation time was determined by spectrophotometric measurement. Based on the counted cell densities and the absorption from an algal suspension and its dilutions, a linear regression was performed for the calculation of the cell densities of the replicates during the test. As a result, the 72-hour EyC50 was calculated to be 9.16 mg test item/L and the ErC50 23.6 mg test item/L. The 72-hour EyC10 was calculated to be 4.54 mg test item/L and the ErC10 6.89 mg test item/L. The 72-hour NOEyC was determined to be 1.6 mg test item/L and the associated 72-hour LOEyC of 5.0 mg test item/L. The 72-hour NOErC was determined to be 1.6 mg test item/L and the associated 72-hour LOErC is 5.0 mg test item/L.