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Whole-sediment toxicity identification evaluation tools for pyrethroid insecticides: II. Esterase addition
Donald P Weston1, Erin L Amweg
1Department of Integrative Biology, University of California, 3060 Valley Life Sciences Building, Berkeley, California 94720-3140, USA. dweston@berkeley.edu
Environmental Toxicology and Chemistry
|October 19, 2007
Summary
An esterase enzyme effectively reduced pyrethroid toxicity in whole sediment tests. However, the method requires further development due to water quality changes and potential misinterpretations.
Area of Science:
- Environmental Toxicology
- Analytical Chemistry
Background:
- Pyrethroid insecticides pose environmental risks.
- Toxicity identification evaluation (TIE) procedures are crucial for assessing contaminant impacts.
- Esterase enzymes offer a potential method for pyrethroid TIE.
Purpose of the Study:
- Validate an esterase enzyme-based TIE procedure for whole sediment samples.
- Determine the efficacy and specificity of the esterase technique for pyrethroids.
- Assess potential interferences and confounding factors in sediment toxicity testing.
Main Methods:
- Standard sediment toxicity tests using the amphipod Hyalella azteca.
- Spiking laboratory and field-collected sediments with pyrethroids.
- Addition of esterase enzyme to overlying water.
- Testing effects of esterase on non-pyrethroid contaminants (DDT, chlorpyrifos, cadmium).
Main Results:
- Esterase addition significantly reduced pyrethroid toxicity in spiked sediments.
- The enzyme did not affect toxicity of DDT or chlorpyrifos.
- Cadmium toxicity was reduced, likely due to complexation, not enzymatic activity.
- Esterase consistently reduced pyrethroid toxicity in 12 field-collected sediment tests.
- The procedure altered water quality and provided nutritional benefits to test organisms.
- Complexation of pyrethroids with esterase or microbial growth contributed to protective effects.
Conclusions:
- The esterase addition technique shows promise for whole-sediment pyrethroid TIE.
- Further procedural development is necessary to mitigate confounding factors.
- Independent validation is required to prevent misinterpretation of results.
