Spent liquor from semi-chemical pulping containing spent inorganic process chemicals and dissolved organic substances originating from the wood raw material

Endpoint summary

Additional information

SCP liquor showed rather low toxicity to aquatic organisms. The most sensitive organism to SCP liquor seemed to be Daphnia magna, based on the key studies. The intrinsic properties of the test substances caused some uncertainty in the test results. There was no available information on long-term toxicity to aquatic organisms, besides one study on effects of primary treated SCP effluent on invertebrates and fish, which showed only low impacts as well.

Invertebrates:

EC50 (48 h) values for Daphnia magna were >100 - >400 mg/l (n=2).

NOEC (48 h): Uncertain, intefered with random immobilisation without dose response.

Algae:

The EC50 (72 h) values for Pseudokirchneriella subcapitata were 1303.2 mg/l and 1318.3 mg/l (growth rate) (n=2).

The NOEC (72 h) values for Pseudokirchneriella subcapitata were 219.2 mg/l and 216.8 mg/l (growth rate) (n=2).

Supporting aquatic toxicity results with invertebrates, algae and bacteria confirmed the rather low short-term toxicity of SCP liquor to the aquatic environment.