4. A Non-Toxic Environment

4. A Non-Toxic Environment. Photo: Göran Nyrén/Johnér Bildbyrå.The occurrence of man-made or extracted substances in the environment must not represent a threat to human health or biological diversity. Concentrations of non-naturally occurring substances will be close to zero and their impacts on human health and on ecosystems will be negligible. Concentrations of naturally occurring substances will be close to background levels.