Contaminants of Emerging Concern: Introduction to a Featured Collection 1

The environmental occurrence of trace organic compounds such as pharmaceuticals, personal care products, pesticides, and hormones, and their potential adverse effects on aquatic and terrestrial life and on human health is an issue that concerns not only scientists and engineers, but also the general public. Such trace organic compounds are being found with increasing frequency in the environment on a global scale (Halling-Sorensen et al., 1998; Kolpin et al., 2002; Ashton et al., 2004; Moldovan, 2006; Gulkowska et al., 2007). Research has shown that there is a wide variety of sources and pathways for these compounds to enter the environment (Campagnolo et al., 2002; Bound and Voulvoulis, 2005; Clara et al., 2005; Glassmeyer et al., 2005; Lindqvist et al., 2005; Brown et al., 2006; Conn et al., 2006; Larsson et al., 2007; Watkinson et al., 2007). Detection capabilities for organic compounds in the environment continue to be refined and detection levels continue to become ever lower. This has lead to the documented presence of many targeted compounds in water resources around the world including in sources of public drinking water (Wiegel et al., 2004; Focazio et al., 2008). Recent studies have focused on questions concerning contaminant environmental fate and behavior (Loffler et al., 2005), as well as wastewater and drinkingwater-treatment efficacies (Stackelberg et al., 2004; Westerhoff et al., 2005). As the evidence mounts that some of these contaminants can have human or ecological health effects (Smital, 2008) there is a need for both better understanding of their fate in environmental systems and better communication of what the results of scientific investigations mean to the general public.