The American Chemical Society National Meeting and Expo is a chance to connect and share ideas with thousands of chemical professionals from around the world. More than 12,000 papers and posters will be presented over the course of the meeting and there will also be the opportunity to meet with more than 200 exhibitors who are showcasing new technological developments in the industry, as well as attend free workshops.
Visit us at Booth 2426 to talk with our team and learn how Charles River can support your chemical registration program and expedite your time to market. We hope you’ll also be able to join our head of environmental fate and metabolism, Chris Lowrie, for his presentation as part of the AGRO: Creative Thinking in Designing Efate Studies & Data Analysis to Meet Agrochemical Regulatory Challenges session.
Sunday, August 25, 11:10 a.m. Ballroom 20B-D Theater 4
Presented by Chris Lowrie
The surface water mineralization test is a laboratory-based simulation test designed to determine the mineralization rate as well as the route and rate of degradation of a chemical in fresh water. The test methods are outlined in OCED TG 309. The data from such studies can be used in both the environmental risk assessment and in the PBT assessment depending on the submission and industry sector. Using the EU as an example, where a degradation rate (DT50) in surface water is >40 days, the active ingredient or chemical fulfils the persistent criterion. If greater than 60 days, then the substance would be classified as vP. It is reasonable to assume that the DT50 in a study with water only would be longer than that observed for the water compartment of a water sediment study (described in OECD TG 308), since the dissipation route to sediment has been eliminated. A badly designed study can therefore have implications downstream when it comes to fulfilment of persistence criteria and the PBT assessment. Modification of the mineralization study to include light (or light / dark cycles) and suspended sediment is allowed according to the test guidance. A series of real study examples will be presented that describe the techniques used to appropriately modify the study conditions. The simplest study design is a pelagic test which is suitable for chemicals which are rapidly mineralized in water or where the degradation rate is rapid. Modification of the test with light/dark cycles using diffuse light provides energy to the test system which is sufficient to promote some biological growth, without impacting the degradation rate through photolytic process. Further modification of the test system with suspended sediment at low concentrations (<0.1 mg/L) is possible and can be a useful addition to provide appropriate biological activity and a surface for the test substance to adhere to. This can be a beneficial technique when the substance adheres to the test apparatus. The presentation will demonstrate that a modified study design need not be complicated, but any modification must be relevant. The endpoint of the study should be considered during design and where modification with light or sediment is preferred, then appropriate controls must be incorporated to determine the influence of the modification on the rate and route of degradation.
For more information on our participation at this event or to schedule a meeting with our attending scientists, please contact us at [email protected].