A comparative study of test methods for assessment of the biodegradability of chemicals in seawater--screening tests and simulation tests
- Water Quality Institute, Horsholm, (Denmark)
A comparative study has been performed on test methods for assessing the biodegradability of chemicals in seawater environments. A simple shake flask die-away test with natural seawater and 14C-labeled chemicals added in microgram/liter concentrations is proposed as a simulation' test. The analytical parameter used in this test is residual dissolved 14C activity. The performance of the simulation test has been compared with the performance of similar screening tests with dissolved organic carbon analysis and test compounds added in mg/liter concentrations to nutrient-enriched seawater. All chemicals investigated that passed the screening tests were also degradable in the simulation test and some results with simulation tests were positive; even screening tests were negative, while some compounds, including maleinhydrazide, known to be degradable in soil, remained undegraded in either type of test. Disappearance times after the ended lag time were smaller in screening tests than in simulation tests, but the rates of biodegradation cannot be meaningfully compared, as zero-order kinetics in combination with an exponentially growing population of degraders prevail in screening tests, while first-order kinetics and frequently a constant activity of degraders (cooxidation) prevail in simulation tests where the test material is a secondary substrate only. In screening tests, lag times are sometimes excessively long and highly variable. Whether the lag times could be decreased and their variability narrowed by supplementation with a cosubstrate (yeast extract) or by inoculation with seawater that had been preadapted to the test material was investigated. In most experiments such test modifications had no significant effect but in one experiment with 4-nitrophenol, inoculation with 1% preadapted seawater decreased the lag phase from greater than 35 to 9 days.
- OSTI ID:
- 5324278
- Journal Information:
- Ecotoxicology and Environmental Safety; (United States), Vol. 23:2; ISSN 0147-6513
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANILINE
BIODEGRADATION
BENZOIC ACID
GLYCOLS
NITROPHENOL
PETN
CARBON 14 COMPOUNDS
COMPARATIVE EVALUATIONS
FEASIBILITY STUDIES
MEASURING METHODS
SEAWATER
SIMULATION
TRACER TECHNIQUES
WATER POLLUTION
ALCOHOLS
AMINES
AROMATICS
CARBON COMPOUNDS
CARBOXYLIC ACIDS
CHEMICAL EXPLOSIVES
CHEMICAL REACTIONS
DECOMPOSITION
ESTERS
EVALUATION
EXPLOSIVES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MONOCARBOXYLIC ACIDS
NITRATES
NITRIC ACID ESTERS
NITRO COMPOUNDS
NITROGEN COMPOUNDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PHENOLS
POLLUTION
WATER
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
560300 - Chemicals Metabolism & Toxicology