Persistent organic pollutants (POPs), sometimes referred to as "forever chemicals" are organic compounds that are immune to environmental degradation through chemical, biological, and photolytic processes. Because of their persistence, POPs bioaccumulate with potential adverse impacts on human health and therefore the environment. The effect of POPs on human and environmental health was discussed, with the intention to eliminate or severely restrict their production, by the international community at the Stockholm Convention on Persistent Organic Pollutants in 2001. Many POPs are currently or were within the past used as pesticides, solvents, pharmaceuticals, and industrial chemicals. Although some POPs arise naturally, for instance , volcanoes and various biosynthetic pathways, most are man-made via total synthesis. POPs typically are halogenated organic compounds (see lists below) and intrinsically exhibit high lipid solubility.