Registration Dossier

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The effects of HMX to aquatic invertebrates was assessed under static conditions in two freshwater and on brackish water acute toxicity studies. The 48h LC50 of the test substance to Daphnia magna is > 15 mg/L (nominal concentration) (U.S. Army Medical Research and Development Command, 1984).The 48h-LC50 of the test substance to macroinvertebrates (Daphnia magna, Gammarus fasciatus, Asellus militaris and Chironomus tentans) was greater than 32 mg/L (nominal concentration) (EG & G Bionomics, 1978).The 96h NOEC of the test substance to Mytilus galloprovincialis was 1.9 mg/L (measured concentration) (US Army Engineer Research and Development Center, 2007).

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
15 mg/L

Additional information

The LC50 values to Daphnia magna are based on nominal concentrations. In the study by the U.S. Army Medical Research and Development Command, (1984), undissolved chemical was present on the bottom of the test vessels. Theses studies were performed at the limit of solubility of HMX (4.46 mg/L at 25C in pure water). A study was conducted using invertebrate reconstituted water at concentrations of 10.0, 5.0 and 2.5 rng/L of HMX. No solvents were utilised. Solutions were analysed immediately, after 24 hours, 48 hours and 1 week of continuous stirring at 25C. These results indicated that the HMX was most completely solubilised between 48 hours and 1 week of mixing and that the expected concentration at saturation should be ca. 2.8 mg/L (see Table 1).

Table 1: Solubility of Test substance in Invertebrate Dilution Water

Sample Concentration

Analytical Results (mg/L)

Remarks

0 hoursa

24 hoursa

48 hoursa

1 weeka

2.5 mg/L Invert.

0.02

0.04

0.04

mean=0.04

0.85

0.86

0.83

mean=0.85

1.7

2.3

mean=2.0

2.6

2.5

mean=2.6

@ 48h, tepm. 27° due to heat from magnetic stir plate and remained warmer than others throughout the study

5.0 mg/L Invert.

0.06

0.07

0.07

mean=0.07

0.36

0.40

0.38

mean=0.38

0.52

0.63

mean=0.58

1.4

1.4

mean=1.4

@ 48h, tepm. 25.8°

10 mg/L Invert.

0.19

0.20

0.25

mean=0.21

0.63

0.63

0.62

mean=0.63

1.8

1.8

mean=1.8

3.3

3.4

mean=3.4

@ 48h, tepm. 25.5°

aRepresents amount of time mixed prior to analysis.