A Hydrosphere Research client was routinely experiencing chronic toxicity to the water flea test species. Their IC25s would range from 60 to 70%. This resulted in test failures and additional testing.
Dr. Smart at the Smart Group noticed that the pH in client’s sample would typically increase over each 24-hour test period. Dr. Smart suspected that this was a contributing factor to their toxicity. In order to control pH drift, Hydrosphere designed a study using sealed glass chambers with the test organisms and small amounts of carbon dioxide.
The results were dramatic. Since implementing this study design, the pH drift has been corrected and the client has passed every test with IC25s greater than 100%. Below is an example of the effectiveness of this study design.