In the past decade, there has been a boost in the industry development in Vietnam, which is the cause of increased heavy metal release in the environment. The study presents the results of voltammetric analysis of heavy metals (Cu, Zn, Cd, Pb) and arsenic in water, sediments and 38 macrophyte species from the coastal area of Northern and Central Vietnam. The effects of sampling station location, depth, and algal divisions/species on elemental concentrations in the macrophytes were tested. Among the macrophyte species, the highest elemental concentrations were found in the red alga Laurencia sp. (As - 72 mg·kg