Soil, Water/Sediment Metabolism Studies

About Soil, Water and Water/Sediment Metabolism Studies:

Soil, Water and Water/Sediment Studies are higher tiered biodegradation tests meant to simulate the natural environment in which a test substance is applied or enters into.  These studies differ from most standard biodegradation studies based on their complexity and the necessity to derive a pathway through the identification of metabolites over the time course of the study. 

Soil Transformation Studies:

Aerobic and anaerobic soil metabolism studies are applicable to pesticides applied in the field but arealso conducted with pharmaceuticals and general chemicals that may have the potential to be landfilled.Soil metabolism is a critical study in defining a compound’s persistence in the environment, since soil is abundant in microorganisms with P450 enzymes which are uniquely able to metabolize xenobiotics suchas pesticides and pharmaceuticals.  Smither Viscient has decades of experience conducting aerobic and anaerobic soil metabolism studies under EPA and OECD Test Guidelines using both US and European Soils as well as soils from other parts of the world.  Endpoints include DT50, DT75, DT90 along with the identity of any metabolites > 10% for US submission and > 5% at two consecutive time points for European submission.  This information is used to propose a metabolic pathway in soil.


Water /Sediment Transformation Studies:

Aerobic and anaerobic aquatic metabolism studies are applicable to pesticides that are susceptible to spray drift and run-off that can reach water bodies along with pharmaceuticals and general chemicals that are discharged to receiving streams or other bodies of water.   These studies can be conducted under aerobic or anaerobic conditions in order to simulate the natural environment, which is generally aerobic in the upper layers of the water bodies and often anaerobic under or near the sediment surface, especially in warm, stagnant waters.  Like soil metabolism studies, Smithers Viscient has decades of experience conducting these studies with locally collected waters and sediments from both fresh and salt water using both EPA and OECD Test Guidelines.  Other sources and even foreign sources of water and sediment can also be procured.  


Aerobic Mineralization in Surface Water:

The ‘aerobic mineralization in surface water – simulation biodegradation test’ is designed to determine a test substance’s likely hood of persistence in natural waters.  This test is conducted with relatively low concentrations of the test substance in an environment where the microbiota is in shorter supply than in the other soil and water/sediment tests described above.   As with the other studies above, similar endpoints are determined and major metabolites are reported along with a proposed pathway.


Equipment and Instrumentation includes:

  • Walk-in temperature controlled chambers
  • LSC counters
  • Agilent, Shimadzu, Waters HPLC systems
  • Metabolite characterization and identification instrumentation: Sciex 4000 QTRAP® and accurate mass Sciex Triple TOF 5600 Q® mass spectrometers