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The existing data on aquatic toxicity of Green liquor sludge fulfils the minimum (Annex VII-VIII) requirements and has been generated with standard organisms and standardized methods.Therefore the information can be used to perform the effects' assessment and PNEC water derivation.

All the tests were carried out applying WAF method and results are reported for nominal total test substance loadings. Test were carried out using non dried wet GLS to avoid changes in the test material during drying process. (Dry weigtht to wet weight conversation in the year 2010 reference samples: dry matter 46,7%, water 53.3%). Non-dissolved test material is included to the reported concentrations, even though all solutions were filtered before tests to get clear solutions.

Fish LC50 (Lethal Loading LL50) 96h based on the nominal (WAF) test substance loading rate was > 4950 mg/l (dwt.) and acute NOEC was also > 4950 mg/l for zebrafish (Danio rerio).

For the aquatic invertebrate Daphnia magna the observed effective loading rate EL50 48h was 4950 mg/l (dwt.), which was also the highest nominal test concentration. The no effect level NOEL for immobility was 77 mg/l (wet wt.) (36 mg/l dry wt.).

 

For the green algae Pseudokirchneriella subcapitata a 50% growth rate inhibition value ErC50/ErL50 (72 h) was 12 883 mg/l (wet wt.) (6055 mg/l (dwt.)). The NOEC/NOEL (0 -72h) was below the lowest test concentration < 38 mg/l (wet wt.) (< 20 mg/l dry wt.) and therefore the test cannot be regarded as a chronic test.

Long-term testing, a 21 day Daphnia reproduction test (OECD 211), was a logical further step in environmental hazard evaluation of GLS. 

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

A chronic 21 day Daphnia magna reproduction study in the year 2012 gave a NOEC value 160 mg/l (dry wt.). This result (NOEC) was used as a basis of PNEC derivation and for environmental CLP Chronic classification. 

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