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Reference
Endpoint:
biodegradation in water: sediment simulation testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data is from peer reviewed journal
Justification for type of information:
Data is from peer reviewed journal
Reference:
Composition 1
Qualifier:
according to
Guideline:
other: as mentioned below
Principles of method if other than guideline:
Biodegradation in water and sediment study was carried out for determing the half-life of test chemical 1-[(2-methoxyphenyl)azo]-2-naphthol.
GLP compliance:
not specified
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material: 1-[(2-methoxyphenyl)azo]-2-naphthol
- Common name: Solvent Red 1
- Molecular formula: C17H14N2O2
- Molecular weight: 278.31 g/mol
- Smiles notation: c12c(\N=N\c3c(cccc3)OC)c(ccc1cccc2)O
- InChl : 1S/C17H14N2O2/c1-21-16-9-5-4-8-14(16)18-19-17-13-7-3-2-6-12(13)10-11-15(17)20/h2-11,20H,1H3/b19-18+
- Substance type: Organic
- Physical state: solid
Radiolabelling:
not specified
Oxygen conditions:
anaerobic
Inoculum or test system:
other: Lake water
Details on source and properties of sediment:
- Details on collection (e.g. location, sampling depth, contamination history, procedure): Sediments were obtained from 2 different lakes (i.e, Herrick and Kingfisher) near Athens, GA.
- Storage conditions: The sieved sediment (5-15 cm deep) was stored in the dark, under lake water, in sealed, 2-gal glass or plastic bottles until used.
- Storage length: The sieved sediment (5-15 cm deep) was stored until used.
- Organic carbon (%): Organic carbon content of sediments was determined at the University of Georgia Soil Testing Laboratory by the Walkley-Black method and by three other combustion methods, including that of Lee and Macalady. In general, the methods gave comparable results.
The percent organic carbon for each lake sediment was as follows: Beef Pond, 3.05 ± 14% (n =9); Herrick, 1.52 :l:
56% (n = 31); KingfIsher, 7.46:l: 45% (n = 10); Oglethorpe, 1.99 :l: 48% (n =7).
- Sediment samples sieved: Yes, sediments were scraped from the top few centimeters of the lake bottom at a water depth of less than about 50 cm and sieved, at the lake, through a 0.5 mm sieve.
Initial conc.:
> 10 - < 98 other: mg/kg
Based on:
test mat.
Initial conc.:
> 10 - < 23 other: mg/kg
Based on:
test mat.
Parameter followed for biodegradation estimation:
other: HPLC and GC
Key result
Compartment:
other: sediment
Half-life:
4 d
Type:
(pseudo-)first order (= DT50)
Remarks on result:
other: Sediment was obtained from Herrick lakes.
Key result
Compartment:
other: sediment
Half-life:
2.2 d
Type:
(pseudo-)first order (= DT50)
Remarks on result:
other: Sediment was obtained from Kingfisher lakes.
Other kinetic parameters:
other: For all kinetic experiments, rate constants for dye loss, kL, was obtained as slope of a regression of logarithm dye concentration versus time.
Transformation products:
yes
No.:
#1
Reference substance:
Composition 1
No.:
#2
Reference substance:
Composition 1
Details on transformation products:
Products of the azo dye, SR 1, were expected to be o-anisidine and 1-amino-2-naphthol resulting from reductive cleavage of the azo bond. However, these compounds could not be identified by HPLC because they coeluted. After GPC cleanup, each product was detected by GC-MS with both spectra and retention times identical to those of purchased materials.
Evaporation of parent compound:
not specified
Volatile metabolites:
not specified
Residues:
not specified

Control studies showed recoveries· to be both high (>90%) and reproducible (±10%).

 

Table: Kinetic Data for chemicalin Sediment-Water Systems.

 

Dye

sediment

D0b(mg/kg)

Di/D0e

K (h-1)d

ne

T1/2 (days)

SR1

H

 

 K

10-98

 

 10-23

1.3

 

 0.8

7.2 × 10-3[62]

1.3 × 10-2 [78]

3

 

 7

4.0

 

 2.2

 

Where,

H = sediment from Herrick

K = sediment from Kingfisher

b = initial dye concentration or range

d = Average first order rate constant and coefficient of variation [ ].

e = No. of range constants

f = Half-life

Validity criteria fulfilled:
not specified
Conclusions:
The half-life value of test chemical 1-[(2-methoxyphenyl)azo]-2-naphthol in sediment obtained from 2 different lakes (i.e, Herrick and Kingfisher) was determined to be 4.0 and 2.2 days with an average first order rate constant of 7.2 × 10-3 and 1.3 × 10-2, respectively.
Executive summary:

Biodegradation in water and sediment study was carried out for determining the half-life of test chemical 1-[(2-methoxyphenyl)azo]-2-naphthol (CAS no 1229 -55 -6) under anaerobic conditions. Sediments were obtained from 2 different lakes (i.e, Herrick and Kingfisher) near Athens, GA. The sieved sediment (5-15 cm deep) was stored in the dark, under lake water, in sealed, 2-gal glass or plastic bottles until used.Organic carbon content of sediments was determined at the University of Georgia Soil Testing Laboratory by the Walkley-Black method and by three other combustion methods, including that of Lee and Macalady.Ingeneral, the methods gave comparable results. The percent organic carbon for each lake sediment was as follows: Beef Pond, 3.05 ± 14%(n=9); Herrick, 1.52 :l:56% (n=31); KingfIsher, 7.46:l: 45%(n=10); Oglethorpe, 1.99 :l: 48%(n=7). Sediments were scraped from the top few centimeters of the lake bottom at a water depth of less than about 50 cm and sieved, at the lake, through a 0.5 mm sieve.The desired amount of sediment (based on wet weight and moisture content of filter cake) in lake water was sealed and allowed to remain quiescent for 2-4 days prior to dye addition. During dye addition (in ACN) and mixing, the sediment was maintained under N2 until placement in 20-mL scintillation vials. No attempt was made to measure redox potentials in the compacted sediment of either kinetic or product studies. However, under the study conditions, the reddish Georgia clay sediment quickly became the light gray color that is characteristic of reducing environments.Vials were sacrificed for analysis by shaking, sonicating, and filtering. To a portion of the filter cake was added a volume of ACN equal to twice the sediment moist weight. The vial was then shaken and sonicated and the slurry was filtered.Test chemical was identified by analytical methods such as HPLC and GC. For all kinetic experiments, rate constants for dye loss,kL,were obtained as the slope of a regression of the logarithm of dye concentration versus time.Products of the azo dye, SR 1, were expected to be o-anisidine and l-amino-2-naphthol resulting from reductive cleavage of the azo bond. However, these compounds could not be identified by HPLC because they coeluted. After GPC cleanup, each product was detected by GC-MS with both spectra and retention times identical to those of purchased materials.The half-life value of test chemical 1-[(2-methoxyphenyl)azo]-2-naphthol in sediment obtained from2 different lakes (i.e, Herrick and Kingfisher) was determined to be 4.0 and 2.2 days with an average first order rate constant of 7.2 × 10-3and 1.3 × 10-2, respectively. Based on this half-life value, it indicates that 1 -[(2 -methoxyphenyl)diazenyl]-2 -naphthol is not persistent in sediment.

Description of key information

Biodegradation in water and sediment study was carried out for determining the half-life of test chemical 1-[(2-methoxyphenyl)azo]-2-naphthol (CAS no 1229 -55 -6) under anaerobic conditions (George L. Baughman and Eric J. Weber, 1994). Sediments were obtained from 2 different lakes (i.e, Herrick and Kingfisher) near Athens, GA. The sieved sediment (5-15 cm deep) was stored in the dark, under lake water, in sealed, 2-gal glass or plastic bottles until used. Organic carbon content of sediments was determined at the University of Georgia Soil Testing Laboratory by the Walkley-Black method and by three other combustion methods, including that of Lee and Macalady.Ingeneral, the methods gave comparable results. The percent organic carbon for each lake sediment was as follows: Beef Pond, 3.05 ± 14%(n=9); Herrick, 1.52 :l:56% (n=31); KingfIsher, 7.46:l: 45%(n=10); Oglethorpe, 1.99 :l: 48%(n=7). Sediments were scraped from the top few centimeters of the lake bottom at a water depth of less than about 50 cm and sieved, at the lake, through a 0.5 mm sieve.The desired amount of sediment (based on wet weight and moisture content of filter cake) in lake water was sealed and allowed to remain quiescent for 2-4 days prior to dye addition. During dye addition (in ACN) and mixing, the sediment was maintained under N2 until placement in 20-mL scintillation vials. No attempt was made to measure redox potentials in the compacted sediment of either kinetic or product studies. However, under the study conditions, the reddish Georgia clay sediment quickly became the light gray color that is characteristic of reducing environments.Vials were sacrificed for analysis by shaking, sonicating, and filtering. To a portion of the filter cake was added a volume of ACN equal to twice the sediment moist weight. The vial was then shaken and sonicated and the slurry was filtered.Test chemical was identified by analytical methods such as HPLC and GC. For all kinetic experiments, rate constants for dye loss,kL,were obtained as the slope of a regression of the logarithm of dye concentration versus time.Products of the azo dye, SR 1, were expected to be o-anisidine and l-amino-2-naphthol resulting from reductive cleavage of the azo bond. However, these compounds could not be identified by HPLC because they coeluted. After GPC cleanup, each product was detected by GC-MS with both spectra and retention times identical to those of purchased materials.The half-life value of test chemical 1-[(2-methoxyphenyl)azo]-2-naphthol in sediment obtained from2 different lakes (i.e, Herrick and Kingfisher) was determined to be 4.0 and 2.2 days with an average first order rate constant of 7.2 × 10-3and 1.3 × 10-2, respectively. Based on this half-life value, it indicates that 1 -[(2 -methoxyphenyl)diazenyl]-2 -naphthol is not persistent in sediment.

Key value for chemical safety assessment

Half-life in sediment:
4 d

Additional information

Biodegradation in water and sediment study was carried out for determining the half-life of test chemical 1-[(2-methoxyphenyl)azo]-2-naphthol (CAS no 1229 -55 -6) under anaerobic conditions (George L. Baughman and Eric J. Weber, 1994). Sediments were obtained from 2 different lakes (i.e, Herrick and Kingfisher) near Athens, GA. The sieved sediment (5-15 cm deep) was stored in the dark, under lake water, in sealed, 2-gal glass or plastic bottles until used.Organic carbon content of sediments was determined at the University of Georgia Soil Testing Laboratory by the Walkley-Black method and by three other combustion methods, including that of Lee and Macalady.Ingeneral, the methods gave comparable results. The percent organic carbon for each lake sediment was as follows: Beef Pond, 3.05 ± 14%(n=9); Herrick, 1.52 :l:56% (n=31); KingfIsher, 7.46:l: 45%(n=10); Oglethorpe, 1.99 :l: 48%(n=7). Sediments were scraped from the top few centimeters of the lake bottom at a water depth of less than about 50 cm and sieved, at the lake, through a 0.5 mm sieve.The desired amount of sediment (based on wet weight and moisture content of filter cake) in lake water was sealed and allowed to remain quiescent for 2-4 days prior to dye addition. During dye addition (in ACN) and mixing, the sediment was maintained under N2 until placement in 20-mL scintillation vials. No attempt was made to measure redox potentials in the compacted sediment of either kinetic or product studies. However, under the study conditions, the reddish Georgia clay sediment quickly became the light gray color that is characteristic of reducing environments.Vials were sacrificed for analysis by shaking, sonicating, and filtering. To a portion of the filter cake was added a volume of ACN equal to twice the sediment moist weight. The vial was then shaken and sonicated and the slurry was filtered.Test chemical was identified by analytical methods such as HPLC and GC. For all kinetic experiments, rate constants for dye loss,kL,were obtained as the slope of a regression of the logarithm of dye concentration versus time.Products of the azo dye, SR 1, were expected to be o-anisidine and l-amino-2-naphthol resulting from reductive cleavage of the azo bond. However, these compounds could not be identified by HPLC because they coeluted. After GPC cleanup, each product was detected by GC-MS with both spectra and retention times identical to those of purchased materials.The half-life value of test chemical 1-[(2-methoxyphenyl)azo]-2-naphthol in sediment obtained from2 different lakes (i.e, Herrick and Kingfisher) was determined to be 4.0 and 2.2 days with an average first order rate constant of 7.2 × 10-3and 1.3 × 10-2, respectively. Based on this half-life value, it indicates that 1 -[(2 -methoxyphenyl)diazenyl]-2 -naphthol is not persistent in sediment.