Pressure on animal testing has traditionally been the purview of mammalian toxicological science, but in the past few years, needs have also emerged in the realm of environmental safety.  The issue has been primarily driven by European legislation, including the UK Animal Protection Act, the 7^th Amendment to the EU Cosmetics Directive, selected legislation in Germany, and the adopted European chemical legislation known as REACh.  Additional ecotoxicity data are sought in many of these legislative efforts, while also promoting non-animal testing / alternative strategies.  There is a clear need to develop alternatives that are quicker and use fewer animals.  As with higher vertebrate animal alternatives, the balance sought is to reduce animal use without impairing or increasing uncertainty in risk assessment.