Registration Dossier

Diss Factsheets

Administrative data

Hazard for aquatic organisms

Hazard for air

Hazard for terrestrial organisms

Hazard for predators

Additional information

SCP liquor is registered as a transported isolated intermediate and is manufactured and consumed during its whole life cycle under strictly controlled conditions. The derivation of PNECs is required for the chemical safety assessment (CSA) of substances manufactured/imported/used in quantities from 10 t/a onwards. CSA does not need to be performed for transported isolated intermediates.

The conclusion on classification is based on aquatic acute toxicity data according to Annex VII in the REACH regulation, applied for transported isolated intermediates, where no terrestrial or long-term aquatic toxicity information is required.

No data on sediment or terrestrial toxicity of SCP liquor was available based on an extensive literature search. SCP liquor recycles in the pulping process and no spillages occur in normal process conditions. Hence little ecotoxicological studies have been conducted on SCP liquor.

The few reported studies available concerned short-term toxicity to aquatic invertebrates, aquatic algae and bacteria, and in one case long-term toxicity to invertebrates and fish of a related substance, which were evaluated as supporting results.

The EC50 (48 h) values for invertebrates varied from >100 mg/l up to >10000 mg/l. The EC50 (72 h) values for algae.were ca. 1300 mg/l (growth rate) up to >4000 mg/l. NOEC (48 h) values for Daphnia magna in the key studies were inconsistent due to lack of dose response, whereas NOEC (72 h) values for Pseudokirchneriella subcapitata were ca. 200 mg/l (growth rate).

SCP liquor did not show short-term toxicity < 100 mg/l to any of the test organisms. Therefore no acute toxicity driven classification is required. As well SCP liquor was regarded as readily biodegradable (5.2.1).

Conclusion on classification

Spent liquor from semi-chemical pulping (SCP liquor) is a process liquor from CTMP and NSSC pulping obtained after treatment of wood raw material with process chemicals. The source materials are softwood, hardwood and process chemicals. Dry substance content of SCP liquor varies from 5 to 77% depending on the degree of evaporation. SCP liquor is a UVCB substance with a fluctuating composition. Therefore the ecotoxicological properties are somewhat variable as well.

The ecotoxicological properties (Annex VII, REACH regulation) of two representative SCP liquor samples were tested by the Seibersdorf Labor GLP laboratory during 2009-2010 (the Key studies). The endpoints for which some additional supporting or weight-of-evidence data was available in the literature were Short- and long-term toxicity to fish, Short- and long-term toxicity to aquatic invertebrates, and Toxicity to algae and microorganisms.

No data was found for ecotoxicological endpoints other than those referred in the endpoint records, through extensive literature searches. SCP liquor is registered as a transported isolated intermediate and no testing outside Annex VII in the REACH regulation is required.


According to the experimental results the ecotoxicological and degradability properties of SCP liquor were:

­  Not acutely toxic to aquatic algae (EC50 >100 mg/l),

­  Not acutely toxic to aquatic invertebrates (EC50 >100 mg/l).

- Readily bioderadable * (Biodegradability 81% (and 68%), 28d

(* SCP liquor is regarded as readily biodgradable despite of the slight failure of the other test sample)


According to the supporting studies the ecotoxicological properties of SCP liquor were:

­  Not acutely toxic to aquatic algae (EC50 >100 mg/l),

­  Not acutely toxic to aquatic invertebrate (EC50 >100 mg/l).


Additionally, the need for classification according to the CLP and DSD/DPD rules was evaluated based on the identified main ingredients, but none of them holds a harmonized classification for aquatic hazard.

No Observed Effects Concentrations for aquatic organisms were:

Daphnia magna, NOEC (48 h), Not reliable due to lack of dose response,

Pseudokirchneriella subcapitata, NOEC (72 h) ca. 200 mg/l (growth rate).

The proposed classification derived from the experimental results of SCP liquor is based on acute aquatic toxicity to the most sensitive organism and on biodegradation (5.2.1):


CLP:                                No class

DSD/DPD:                        No class