Heavy metal pollution in water and sediment endangers human health and the environment. To battle this problem a purification strategy, in which arsenic, zinc and copper are removed from water and sediment, was developed. This strategy encompasses a biological device in which E. coli bacteria accumulate metal ions from solutions, after which they produce gas vesicles and start floating. This biological device consists of two integrated systems: one for metal uptake and storage, the other for metal induced buoyancy. The uptake and storage system consists of a metal transporter and metallothioneins (metal accumulators). The buoyancy system is made up of a metal induced promotor in front of a gas vesicle gene cluster. The combination of both systems will enable the efficient cleaning of polluted water and sediment in a biological manner.