Charcoal

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted accroding to the respective OECD guideline and under GLP conditions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

yes

Remarks:

Temperature was slightly lower (18.4 to 23.7°C) than stated in the guidelin (22±2°C). 2. Air supply was interrupted for 90 min, because of a technical problem.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

yes

Remarks:

see above

Principles of method if other than guideline:

A measured volume of inoculated mineral medium, containing a known concentration of the test substance (10-20 mg DOC or TOC/l) as the nominal sole source of organic carbon is aerated by the passage of carbon dioxide-free air at a controlled rate in the dark or in diffuse light. Degradation is followed over 28 days by determining the carbon dioxide produced.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Charcoal

EC Number:

240-383-3

EC Name:

Charcoal

Cas Number:

16291-96-6

IUPAC Name:

Carbón vegetal

Details on test material:

Name: Charcoal (Probe 2: C-Fix =80.5%)
Batch no.: 29004
Appearance: Charcoal typic
CAS no.: 16291-96-6
EINECS-no.: 240-383-3
Purity: C-Fix: 80.5%
Expiry date: Dec. 2030
Storage: Room temperature 20 ± 5 °C, keep away from humidity

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
no aplicableaeae

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Specification:
Activated sludge from a biologic sewage treatment plant was used. The chosen plant is predominantly treating domestic sewage.

Source:
The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf.
Date of collection: 03. Sept. 2010, batch no.: 20100903.

Pre-Treatment:
The sludge was filtrated, washed with tap water twice, then washed with and resuspended in test medium. It was then aerated for ≥ 12 hours. The dry matter was determined with 4520 mg suspended solids/L.

Duration of test (contact time):

ca. 28 d

Initial test substance concentration

Initial conc.:

ca. 25 mg/L

Based on:

other: TOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

The temperature was in a range of 18.4 to 23.7°C and therefore slightly lower than stated in the guideline (22 ± 2°C). As all validity criteria were met, this deviation can be stated as uncritical.

Reference substance

Reference substance:

aniline

Remarks:

73 % DOC

Results and discussion

Preliminary study:

no aplicable

Test performance:

Samples were collected on day 0, 2, 4, 9, 11, 14, 18, 23, 29. The sample volume was 1 mL. The emitted CO2 was determined by IC measurement using a carbon analyser. Each sample was measured at least in duplicate.

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

< 2

Details on results:

no aplicable

BOD5 / COD results

Results with reference substance:

The degradation of the reference substance was 64% after 9 d.

Any other information on results incl. tables

El porcentaje de biodegradación en los matraces de ensayo se calculó a partir de:

% Degradación = ((emitida C (matraz de prueba) en mg / l - significa que emite C (controles del inóculo), en g / L) x 100) / C añadido en mg / l

La degradación en el control positivo y el control de la toxicidad se ha calculado de forma análoga.

La degradación abiótica se calcula a partir de:

% De degradación abiótica = (mg emitida C (abiótico) x 100) / C añadido en mg / l

 

 

 

 

A continuación aparecen los datos obtenidos en el estudio.

Día	Inóculo de control 1	Inóculo de control 2	Control Positivo	Control Positivo 2	Prueba Flask1	Ensayo en Matraz 2	Control abiótico	La toxicidad de control
2	0,30	0,13	0,05	0,23	0,06	0,09	0,17	0,24
4	0,28	0,23	3,15	3,38	0,11	0,09	0,04	4,09
7	0,81	0,94	13,33	9,76	0,69	0,78	0,10	13,35
9	1,16	1,25	15,89	12,12	0,96	1,11	0,01	16,06
11	1,29	1,08	16,88	15,49	1,18	1,36	-0,01	16,81
14	1,93	1,51	18,41	18,17	1,57	1,81	-0,04	18,52
18	2,02	1,93	19,76	19,51	1,91	2,43	-0,10	20,04
23	2,44	2,37	19,69	20,15	2,15	2,38	-0,21	19,11
29	2,80	2,10	18,42	19,66	2,47	2,93	-0,03	19,23

En la siguiente tabla se presenta el porcentaje de biodegradación (% de degradación, calculado según la ecuación dada más arriba).

Día	Control Positivo	Control Positivo 2	Control Positivo Media	Ensayo en Matraz 1	Ensayo en Matraz 2	Prueba de medias	Control abiótico	La toxicidad de control
2	-0,8	0.0	-0,4	-0,8	-0,6	-0,7	0.9	0.0
4	14,2	15,4	14,8	-0,7	-0,8	-0,8	0.2	9.5
7	61,4	43,8	52,6	-0,9	-0,5	-0,7	0.5	30,9
9	72,3	53,8	63,1	-1,2	-0,5	-0,9	0.1	36,8
11	77,3	70,5	73,9	0.0	0.9	0.4	-0,1	38,8
14	82,3	81,1	81,7	-0,7	0.4	-0,2	-0,2	41,7
18	87,7	86,4	87,0	-0,3	2.3	1.0	-0,5	44,8
23	85,2	87,5	86,3	-1,3	-0,1	-0,7	-1,1	41,4
29	78,7	84,8	81,7	0.1	2.4	1.2	-0,2	41,6

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test item charcoal is not readily biodegradable according to OECD 301B.