Environmental protection has advanced in leaps and bounds over recent years and today we undoubtedly live in a much cleaner world than we did a generation ago. But look closely and all is not what it seems. Rather than reducing pollution, we are, in fact, still bathed in a sea of chemicals. What is more, most of them originate not from factories or agriculture but from our own homes, in the form of drugs and consumer products. Tackling these diffuse sources presents one of the main environmental challenges of the 21st century.