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

Toxicity to aquatic plants other than algae

Administrative data

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Not a guideline study

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2004

Materials and methods

Principles of method if other than guideline:

Different types of solid waste from KRAFT pulping process were mixed to different types of soil/substrate, and seed from different types of plants were planted in the mixtures in order to measure the effects of the dreg addition to germination and growth (height or fresh weight) of the plants.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Automatically generated during migration to IUCLID 6, no data available

IUPAC Name:

Automatically generated during migration to IUCLID 6, no data available

Details on test material:

Solid residues from Kraft pulping process: ashes, primary sludge, fly-ash, dregs, grits, and brown stock rejects.

Sampling and analysis

Analytical monitoring:

no

Test solutions

Details on test solutions:

Hoagland's Medium was used in combination with the different residual materials in ratio 2,5 parts residue to 7,5 parts HM.

Test organisms

Test organisms (species):

Lemna minor

Details on test organisms:

No data other than the name of the species was given.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

50 d

Test conditions

Hardness:

No data.

Test temperature:

23-25 °C

pH:

Control: 4,80 Control, dregs: 8,81, ash: 9,16, fly-ash: 7,96, p.sludge: 8,10, b.rejects: 7,18, grits: 10,25

Dissolved oxygen:

No data

Salinity:

No data

Nominal and measured concentrations:

No data

Details on test conditions:

The duckweed fronds were cultivated In vitro in growth chambers provided with fluorescent lamps (Philips TLD 36W/54) with a photon flux of 45µmol/m2/s.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

50 d

Dose descriptor:

other: number of fronds/flask

Effect conc.:

25 other: % of the total substrate volume

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

frond number

Remarks on result:

other: control: 295,0 fronds

Effect concentrations 2

Duration:

50 d

Dose descriptor:

other: number of fronds/flask

Effect conc.:

25 other: % of the total substrate volume

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

frond number

Remarks on result:

other: Dregs: 284,5 fronds

Effect concentrations 3

Duration:

50 d

Dose descriptor:

other: number of fronds/flask

Effect conc.:

25 other: % of the total substrate volume

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

frond number

Remarks on result:

other: Ash: 128,5 fronds

Effect concentrations 4

Duration:

50 d

Dose descriptor:

other: number of fronds/flask

Effect conc.:

25 other: % of the total substrate volume

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

frond number

Remarks on result:

other: Fly-ash: 422 fronds

Effect concentrations 5

Duration:

50 d

Dose descriptor:

other: % of the total substrate volume

Effect conc.:

25

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

frond number

Remarks on result:

other: P.sludge: 363,3 fronds

Effect concentrations 6

Duration:

50 d

Dose descriptor:

other: number of fronds/flask

Effect conc.:

25 other: % of the total substrate volume

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

frond number

Remarks on result:

other: B.rejects 204,0 fronds

Effect concentrations 7

Duration:

50 d

Dose descriptor:

other: total number of fronds/flask

Effect conc.:

25 other: % of the total substrate volume

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

frond number

Remarks on result:

other: Grits: 10,5 fronds

Details on results:

For duckweed, a higher number of fronds and fresh weight were found in the presence of fly-ash and primary sludge in spite of the high pH values of the media (initial pH close to 8), as compared to plants developed in Hoagland's nutrient solution alone 8pH 4,8), after a 50-day culture period. The results are presented in table I.In contrast, ash, brown stock rejects, and especially grits strongly inhibited growth, causing chlorosis and early death of new fronds. It is assumed that other components present in these residues can account for these effects, besides the high pH levels.

Any other information on results incl. tables

Table I. Growth responses of duckweed (Lemna minor) developing in the presence of cellulose mill residues.

Residue (Waste:HM^aratio)	Fronds/Flask	Fresh weight (mg)	pH
Control (0:10)	295,0	365	4,80
Dregs (2,5:7,5)	284,5	399	8,81
Ash (2,5:7,5)	128,5	198	9,16
Fly-ash (2,5:7,5)	355,6	422	7,96
Primary sludge(2,5:7,5)	363,3	710,3	8,10
Brown rejects (2,5:7,5)	204,0	344	7,18
Grits (2,5:7,5)	10,5	4,3	10,25

^aHoagland’s Medium

Applicant's summary and conclusion

Conclusions:

In the presence of fly-ash and primary sludge the growth of duckweed was enhanced. Ash, brown stocke rejects and grits srtongly inhibited growth and caused early death and chlorosis in the fronds. It is assumed that other components present in these residues can account for this effect besides the high pH levels.