Science-Based Guidance and Framework for the Evaluation and Identification of PBTs and POPs: Summary of a SETAC Pellston Workshop

There is a growing sense of urgency among scientists and environmental policy-makers concerning the need for improving the scientific foundation supporting international regulations for identifying and evaluating persistent,bioaccumulative, and toxic (PBT) substances and persistent organic pollutants (POPs) in the environment. The current national and international regulations define PBTs and POPs in terms of fairly strict criteria that are based on the state of the science in the late 1970s and early 1980s. Since then, an evolution in the state of the science has produced new insights into PBT substances and an array of new methods to identify PBT chemicals. The development of regulatory criteria has not kept up with the rapid development in environmental chemistry and toxicology, and as a result, scientists often find themselves in the situation where guidance on PBT and POPs criteria is limited and, in some respects, out of date. With this background,a Society of Environmental Toxicology and Chemistry (SETAC) Pellston Workshop brought together experts from academia,government, and industry to reach consensus on the significance of advancements in our understanding of the behavior and potential impact of POPs and PBTs in the environment, the current understanding of the state of the science, as well as recommendations for policy-makers to improve and coordinate national and international regulations on this issue. The workshop builds on the outcome of a previous Pellston workshop, held in 1998, which focused on the evaluation of persistence and long-range transport of organic chemicals in the environment, and is linked to other recent Pellston workshops, among them the Tissue Residue Approach for Toxicity Assessment workshop held in 2007. The results of this workshop are conveyed in a series of 9 articles, published in this issue of Integrated Environmental Assessment and Management, and describe the coordination of science, regulation, and management needed to more effectively achieve a common goal of managing chemicals on our planet

Experiments in Predicting Biodegradability

. We present a novel application of inductive logic programming (ILP) in the area of quantitative structure-activity relationships (QSARs). The activity we want to predict is the biodegradability of chemical compounds in water. In particular, the target variable is the half-life in water for aerobic aqueous biodegradation. Structural descriptions of chemicals in terms of atoms and bonds are derived from the chemicals' SMILES encodings. Definition of substructures are used as background knowledge. Predicting biodegradability is essentially a regression problem, but we also consider a discretized version of the target variable. We thus employ a number of relational classification and regression methods on the relational representation and compare these to propositional methods applied to different propositionalisations of the problem. Some expert comments on the induced theories are also given. 1 Introduction The persistence of chemicals in the environment (or to environmen..