Inorganic residual from kraft or soda pulping separated from green liquor in the chemical recovery cycle.

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

1.6 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

49.5 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.16 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

333 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

no data available: testing technically not feasible

Sediment (marine water)

Hazard assessment conclusion:

no data available: testing technically not feasible

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

17 700 mg/kg soil dw

Assessment factor:

1

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

PNEC for fresh and marine surface water

The aquatic toxicity dataset is complete enough, and therefore PNEC water can be derived for GLS applying the assessment factor method. Acute test results are available for three trophic levels: fish, invertebrate and algae and a chronic result for invertebrate (Daphnia).

For the characterization of the PNEC it is of high importance to evaluate the data with regard to their adequacy and completeness. The GLS test results cannot be regarded completely acceptable for PNEC water derivation, since there are uncertainties and inconsistencies in the results. These kinds of inconsistencies in test results are not very surprising for a solid, not completely water soluble UVCB substance such as GLS. It is expected that aquatic toxicity is primarily in connection to trace amounts of dissolving heavy metals present in this UVCB substance.

Long-term testing, a 21 day Daphnia reproduction test, was a logical further step in environmental hazard evaluation of GLS. 

Daphnia was clearly more sensitive than fish in short term tests. On this basis further fish testing is currently not seen necessary, since unnecessary vertebrate animal testing should be avoided.

PNECmicrobes (waste water treatment plant)

The tested microbial toxicity dataset is complete enough. A respiration inhibition (OECD 209/C.11) test results (EC50/NOEC) is available for GLS reference sample. This information is sufficient to derive a PNEC_STP(PNEC_{microorganisms}) PNECmicrobes could be derived applying the assessment factor method,

PNEC soil

Tested data on toxicity of GLS to soil living organisms is not available. The equilibrium partitioning method is not directly applicable for inorganic UVCB substance such as GLS and therefore the aquatic test data cannot be applied directly.  It is not possible to carry out the assessment at a quantitative level to derive a PNEC soil value for GLS as a substance.

GLS contains trace levels of toxic constituents (e.g. heavy metals). These constituents become as the limiting factor in determining and quantifying whether emission or application/use of GLS in soil is acceptable or not. Read across method was applied. The PNEC soil value for GLS is determined using individual PNEC vales for these key heavy metal elements (PNECs determined under Regulation ESR-ERA 793/93).

Conclusion on classification

Acute and Chronic aquatic CLP classification (2nd ATP): GLS is not classified as hazardous to the environment.

CLP/GHS:

Hazards for the aquatic environment: No classification

Reason for no classification:Dataset is conclusive but not sufficient for classification.

Hazardous to the atmospheric environment: No classification

Reason for no classification: The existing Dataset is conclusive but not sufficient for classification.

 

DSD:

Environment:No classification.

Reason for no classification:Dataset is conclusive but not sufficient for classification.

Justifications for classifications:

The available data on the aqautic toxicity of Green liquor sludge fulfills the minimum (Annex VII-VIII) requirements and has been generated with standard organisms and standardized methods. Therefore the information is relevant for the environmental classification of aquatic effects.

All the tests on Green liquor sludge (GLS) were carried out applying the WAF (water accomodated fractions) method, and the results are reported for nominal total test substance loadings including the insoluble test material even though all solutions were filtered before tests to get clear solutions.

Applying the year 2011 CLP criteria (2nd ATP) to GLS test results dataset, it can be seen that the acute dataset is complete (algae, Daphnia, fish) and table 4.1.0 (a) applies for acute aquatic classification. Adequate chronic toxicity data is available for one trophic level (Daphnia) whereas the long-term aquatic classification can be based on a mix of long-term and short-term test data following Figure 4.1.1 in CLP, i.e. both table 4.1.0 b (i) applies for the long-term data and table 4.1.0 b (iii) for the short-term data and the most stringent outcome applies.

Summary table: conclusion on CLP classification

Acute tests	Endpoint/result (dw.)	CLP Classification Criteria	CLP Classification YES/NO  /Criteria Table in CLP Regulation (ver 2011)
Algae	acute EC50 = 6016 mg/l	1 mg/l	NO above the criteria(Table 4.1.0 a)
Invertebrate:Daphnia	acute EC50 = 4950 mg/l	1 mg/l	NO above the criteria(Table 4.1.0 a)
Fish –acute (96 hr)	acute LC50 > 4950 mg/l	1 mg/l	NO above the criteria(Table 4.1.0 a)
Chronic tests
Algae (Not a true chronic study, NOEC is not determined)	EC50 = 6016mg/l          NOEC < 18mg/l	10-100 mg/l   1 mg/l	NO above the criteria(Table4.1.0 biii)   NO may be abovethe criteria (Table 4.1.0 b i/ii)
Invertebrate:Daphnia	acute EC50 = 4950 mg/l Chronic NOEC = 160 mg/l	>1- <10 mg/l1 mg/l	NO above the criteria (Table 4.1.0 b iii)  NO above the criteria (Table 4.1.0 b i/ii)
Fish	NOEC not available	1 mg/l	(Table 4.1.0 b i/ii)

 

Note; 
The available Daphnia magna (OECD 211 reproduction) study from 2012 result shows the chronic 21 day Daphnia NOEC > 1 mg/l.
There were difficulties in the year 2010 algae test and only acute toxicity data was obtained. The NOEC could not be determined and therefore algae NOEC is < 18 mg/L (dwt.) Therefore the test is regarded here as an acute algae test, but not as a valid chronic test.