Passive sampling (Chemcatcher) was applied to monitoring several heavy metals (Cd, Cu, Zn and Ni) in Nhue river (Vietnam). (1) The experiment was investigated sampling rate (Rs, Lh-1) of Chemcatcher defined as the equivalent volume of water extracted per unit time which is affected by temperature and turbulence suitable for Vietnam condition,. | Design an experiment using passive sampling technique for monitoring heavy metals: a case study in Nhue river, Vietnam