Heavy metals are of particular concern as environmental contaminants due to their toxic effects when accumulated within organisms. Under the European Union Water Framework Directive (WFD) 2013/39/EU, cadmium (Cd), nickel (Ni) and lead (Pb) were identified as priority metals of ecological concern which must be mediated to achieve a good environmental status. Widespread implementation of these regulatory policies requires the use of accurate monitoring and analytical techniques, which are often costly, and are a barrier to compliance in some cases. As such, there is a need to further develop and validate low-cost and easy-to-use monitoring and analytical protocols. Passive sampling devices (PSDs) allow for the accumulation of an analyte over time, providing a time weighted average of analyte concentrations in a water body. For heavy metals in solution, the most prominent PSD is the Diffusive Gradients in Thin Films (DGT) device. DGTs measure a fraction of labile metals, often considered to be equivalent to the bioavailable fraction. Such PSDs require definition of appropriate Environmental Quality Standards (EQS) prior to their wider use in a regulatory context. Electrochemical analysis techniques such as stripping voltammetry may be used to analyse trace metals and are cheaper to use and run than traditional metal analysis instrumentation, and can be easily modified to optimise for certain analytes. In this thesis, the potential for the application of PSDs and stripping voltammetry in monitoring programs was advanced. A review of current trace metal monitoring techniques and comparative studies using DGT were presented. Stripping voltammetry was examined as a method of analysis of coastal and estuarine water samples. The impact of biofouling on DGTs was also examined in marine and transitional waters across the Atlantic coast, evaluating speciation and extent of fouling. Taken together, these findings help inform future trace metal monitoring and remediation programs.