Cyclohexane-1,2,4-triyltris(ethylene)

Long-term toxicity to aquatic invertebrates

Description of key information

In a semi-static, long-term test with Daphnids, a NOEC of 44.4 µg/L for reproduction and a LOEC of 115 µg/L has been determined. The EC10 for reproduction is 41.4 µg/L after 21 days. The NOEC for mortality is >=115 µg/L and the LC50 (21 d) > 115 µg/L, as no significant trend in mortality has been detected.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

41.4 µg/L

Additional information

Toxicity of 1,2,4 -Trivinylcyclohexane has been examined in an long-term toxicity study with Daphnia magna for 21 days according to the TG OECD 211 (2012). The study has been conducted in a closed system without headspace under semi-static conditions with daily renewal of the test solutions to consider the physical-chemical properties of the substance (low water solubility, volatile).

5 concentration level has been prepared by dilution of a saturated solution and has been tested in a dose-response test. The saturated solution with a nominal loading of 2 µL/2250 ml (nominal concentration 0.753 mg/L) has been prepared one day prior to each exposure interval by a slow-stirring procedure. 5 concentration levels has been prepared by dilution of the saturated solution with dilution water and the dilution levels 1.28 %, 3.2 %, 8.0 %, 20 % and 50 % have been tested. The analytical verification revealed a concentration range of 1.56 µg/L to 191 µg/L in fresh media (0 h) of each exposure interval and 1.34 µg/L to 137 µg/L in old media (24 h). 47% to 86% of the initial measured concentration were recovered. Therefore, the effect levels were based on the geometric mean of the test substance concentrations, which were reported as 2.34 µg/L, 6.11 µg/L, 16.8 µg/L, 44.4 µg/L and 115 µg/L.

The effects on reproduction are evaluated based on the reproduction per introduced parent daphnid. The ecologically most relevant response variable is the total number of living offspring produced per parent animal which does not die accidentally during the test (surviving parental daphnid). Although no significant trend in mortality has been observed, the evaluation has been based on the cumulative offspring per introducted parent, since these values are lower.

The NOEC for mortality is >=115 µg/L and the LC50 (21 d) > 115 µg/L, as no significant trend in mortality has been detected. The overall effect threshold for effects of the test item under the test conditions was 44.4 µg/L (NOEC) and 115 µg/L (LOEC) based on the geometric mean measured concentrations of the test substance. The EC10 for reproduction is 41.4 µg/L after 21 days.

Further endpoints have been investigated. No stillborn juveniles, aborted eggs, males or ephippia have been observed. The intrinsic rate in the control replicates has been 0.409 and 0.292 to 0.398 in the test substance concentrations. The first living juveniles in the control have been observed on day 8 to 10 and in the test substance concentrations on day 8 to 12. The body length of the survived parental daphnids have been 4.5 to 5.0 mm in the control and 3.25 to 4.75 mm in the test substance concentrations.