There are increasing concerns over the harm being done by so-called 'forever chemicals', and research has now linked some of these substances with weakened bones in children. Per- and polyfluoroalkyl substances (PFAS) have been given their nickname because they stick around so persistently in the environment . They've been used in manufacturing and other industries for decades, and are basically impossible to avoid . In a new study, researchers from across the US and Canada looked at health