“Emerging contaminants” are chemicals that have been detected in global drinking water supplies at trace levels and for which the risk to human health is not yet fully known. They include pharmaceuticals, personal care products, pesticides, herbicides and endocrine-disrupting compounds.
These pollutants have likely been present in our drinking water as long as people have been using them, but advances in analytical technology and instrumentation have made it possible to now detect these contaminants.
Source: https://blogs.scientificamerican.com/guest-blog/emergingcontaminants-taint-drinking-water-supply