On January 26, 2021, the Organization for Economic Cooperation and Development (OECD) will hold a webinar on Guidance Document on Aquatic and Sediment Toxicological Testing of Nanomaterials (No. 317).  The webinar will discuss the scope and use of the guidance document, which addresses practical aspects of carrying out valid tests on nanomaterials, and modifications or additions to OECD Test Guidelines procedures intended to improve the accuracy of test results.  Registration for the webinar is open.