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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Administrative data

Endpoint:
biodegradation in water and sediment: simulation tests
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1978

Materials and methods

Principles of method if other than guideline:
Natural Water Biodegradation and Photodegradation Monsanto shake flask system for CO2 evolution testing (W.E. Gledhill, App. Microbiol. 30, 922 (1975))
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
[ethane-1,2-diylbis[nitrilobis(methylene)]]tetrakisphosphonic acid
EC Number:
215-851-5
EC Name:
[ethane-1,2-diylbis[nitrilobis(methylene)]]tetrakisphosphonic acid
Cas Number:
1429-50-1
Molecular formula:
C6H20N2O12P4
IUPAC Name:
{ethane-1,2-diylbis[nitrilobis(methylene)]}tetrakis(phosphonic acid)

Study design

Details on source and properties of surface water:
TEST DETAILS: Natural waters were obtained from the Meramec River (Kirkwood Park) (pH 7.4, TOC 12 mg/l) and Lake No. 34 - Busch Wildlife Area (pH 8.0, TOC 17 mg/l). These were allowed to settle for 2 days and the supernatant liquid used in 500 ml portions for the test.
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
Six water samples were spiked with a stock solution of the test substance to give a test concentration of 2 mg/l (active acid). Control flasks were similarly spiked with either C-14 labelled linear dodecylbenzene sulfonate (LAS) or glucose (glucose used only for lake water exposure as positive
control). Two of the replicates were then sterilised by the addition of 25 mg HgCl2.
An open reservoir containing 10 ml of 0.5N aqueous KOH was suspended in each flask. After sealing, one set of flasks was placed on a rotary shaker and agitated at 80 rpm at ambient temperature (22 °C) in the dark. A second set was taken to an outdoor platform and exposed to natural sunlight and temperatures.

Results and discussion

Any other information on results incl. tables


Table 1: Percent degradation values at 60 days for reference substances and test substance in river water and lake water

Type of suspension

% degradation at 60 days

River Sterile

Lake Sterile

River Sterile plus light

Lake Sterile plus light

River microbial

Lake microbial

River Microbial plus light

Lake Microbial plus light

Reference Linear dodecylbenzene sulfonate 

3.67

1.19

3.60

1.92

32.08

6.34

1.88

15.35

 

 

 

Reference                       Glucose (Lake only)

-

0.31

-

1.15

-

58.82

-

46.66

 

 

 

Test substance

0.16

0.23

2.61

5.61

6.35, 1.88

6.71, 5.82

11.45, 12.09

19.31, 14.80

 


The effect of temperature variation in the sunlight exposures is an unknown factor. Water temperature reached as high as 44 °C during the test. This may have had a significant impact on the microbial population and distribution.

In general, the lake water appeared somewhat more active than the river water with respect to Dequest degradation.

For LAS, the reverse was true. Much more acclimation from previous exposure to LAS in the river than the lake would be
expected. The reason for the higher activity of the lake water to Dequest is unknown.

Applicant's summary and conclusion

Conclusions:
A degradation rate in river and lake waters of ca. 2 - 7% after 60 days was determined in a reliable study conducted according to generally accepted scientific principles. In the presence of natural light, 11 - 20% degradation was observed over the same time period.

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