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Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: screening test, other
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1987
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to
Guideline:
other: OCDE. Méthode proposée pour la determination de la biodegradabilité des agents de surface utilises dans les detergents synthetiques. Direction de I'Environnement. Paris, 1976.
Version / remarks:
Other guideline mentioned: OCDE, Pollution by Detergents. Determination of the biodegradability of anionic synthetic surface active agents». Paris, 1971.
GLP compliance:
not specified
Oxygen conditions:
aerobic
Inoculum or test system:
sewage, industrial, non-adapted
Remarks:
secondary effluent from a wastewater treatment plant
Details on inoculum:
secondary effluent from a sewage treatment plant
Duration of test (contact time):
ca. 21 d
Initial conc.:
ca. 5 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
test mat. analysis
Details on study design:
a) Selection test.

A certain amount of cationic surfactant is dissolved in a mineral solution to give a final concentration of 5 mg / l of active substance. This solution is inoculated with a small volume of a secondary effluent from a sewage treatment plant and is incubated at 25 ± 1 ° Calabrigodelaluz. The determination of the surfactant concentration is carried out on days 5 and 8 of incubation, and then every two days until the corresponding difference between two sampling takes separated by a period of 4 days is less than 0.15. mg / l. The degradation percentage curve is plotted as a function of time and the result of the test is given by the percentage of the first sample taken corresponding to the point of inflection of the curve. The effectiveness of the biological process is controlled by means of two hard and soft surfactant standards. The result is valid if the percentage of degradation of the soft pattern is between 90 and 95% over a period of 14 days maximum, the hard pattern should not degrade more than 35%. The duration of the test can not pass in any case of the 19 days. For products that do not have a defined inflection point in the degradation curve, the result is obtained at the end of the test, that is, on the 19th day of the test.

b) Confirmation Test.

A synthetic residual water based on mineral salts, peptone, meat extract and urea is used, with a concentration of cationic surfactant of 5 mg / l. This water feeds continuously, by means of a metering pump with a flow of 1 liter / hour, an aeration chamber of 3 liters capacity, which gives a retention time of three hours. The inoculation is also done with a small amount of secondary effluent of good quality from a sewage treatment plant, performing the test at a temperature that must not fall below 18 ° C or exceed 25 ° C. It is necessary to regulate the rate of aeration flow in such a way that the sludge content of the chamber is constantly in suspension and the dissolved oxygen is at least 2 mg / l. After an adaptation period, the normal operating period is 21 days, during which the percentage of degradation is calculated daily from the concentration of surfactant in the synthetic wastewater feed and the corresponding effluent collected. after 24 hours. The percentage of degradation of the product under test is calculated as the average of the values obtained during the 21 days of normal operation. In no case will the duration of adaptation time exceed 6 weeks. The D.Q.O. is determined periodically to check the proper functioning of this laboratory de-oiling plant. of the synthetic wastewater of feeding and of the effluent. Equally It is done with the content of active sludge in the aeration chamber so that they do not exceed 2.5 g / l.
Reference substance:
not required
Preliminary study:
19 days
Test performance:
21 days
Key result
Parameter:
% degradation (test mat. analysis)
Remarks:
preliminary test
Value:
ca. 96
Sampling time:
19 d
Key result
Parameter:
% degradation (test mat. analysis)
Remarks:
Final test
Value:
ca. 95
Sampling time:
21 d
Validity criteria fulfilled:
not specified
Interpretation of results:
readily biodegradable
Conclusions:
Benzyldodecyldimethylammonium bromide is biodegraded by sewage sludge >95% after 19 to 21 days.
Executive summary:

In a study following OECD (1976) test method, the substance constituent benzyldodecyldimethylammonium bromide is biodegraded by sewage sludge >95% after 19 and 21 days.

Endpoint:
biodegradation in water: screening test, other
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
No datail is available on the substance, but relevant read across is identified. Please refer to Attached Justification enclosed document.
Reason / purpose:
read-across source
Preliminary study:
19 days
Test performance:
21 days
Key result
Parameter:
% degradation (test mat. analysis)
Remarks:
by analogy with benzyltetradecyldimethylammonium chloride
Value:
ca. 92
Sampling time:
21 d
Interpretation of results:
readily biodegradable
Conclusions:
By analogy with benzyltetradecyldimethylammonium bromide in a study following OECD (1976) test method, the substance constituent is biodegraded by sewage sludge >92% after 19 and 21 days.
Executive summary:

By analogy with benzyltetradecyldimethylammonium bromide in a study following OECD (1976) test method, the substance constituent benzyltetradecyldimethylammonium chloride is biodegraded by sewage sludge >92% after 19 and 21 days.

Description of key information

Substance biodegradability is based on its constituents properties.

In a study following OECD (1976) test method, the substance constituent benzyldodecyldimethylammonium bromide is biodegraded by sewage sludge >95% after 19 and 21 days.

By analogy with benzyltetradecyldimethylammonium bromide in the same study, the substance constituent benzyltetradecyldimethylammonium chloride s biodegraded by sewage sludge >92% after 19 and 21 days.

Therefore substance is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

[Type of water: freshwater]