Exploring novel ways of using species sensitivity distributions to establish PNECs for industrial chemicals: Final report to Project Steering Group 3 April 2013.

In all of what follows, we are concerned with the problem of estimating the HC5 (concentration hazardous to 5% of species) for a chemical based on the SSD (species sensitivity distribution) concept and using acute data. Data for the chemical will be a limited number of test results (LC50s or appropriate EC50s—hereafter all referred to as EC50s). An EC50 measures the toxicity of a chemical to a particular species or, equivalently, the sensitivity of the species to that chemical. The intention is that parts I, II and III of this report should be accessible to scientists with an expertise in applying species sensitivity distributions while the technical material in the appendices is aimed at computationally-expert Bayesian statisticians.