The1 application of voltammetric methods to the determination of some compounds of environmental1 importance is described. In addition, a comparison of electrochemical (EC) detection and ultraviolet (UV) detection for the quantification of phenolic compounds in beers following separation by high performance liquid chromatography is also illustrated. A field study is described in which differential pulse anodicj stripping voltammetry (DPASV) at a mercury I film electrode (MFE) was used to measure the levels of dissolved cadmium, lead and copper in the Irish Sea. Difficulties encountered with DPASV measurements in rough weather suggest that the method is not suitable for field analyses. In contrast, cold vapour atomic absorption spectroscopyl is Ideally suited to the quantification of mercury In field analyses. A speciation scheme was developed to separately measure inorganic, dimethyl- and trimethyl-lead species in mixtures. Quantification was carried out using DPASV. By using a plating potential of -1.2V the three lead species are simultaneously measured. When the plating potential is decreased to -0.6V only inorganic and dimethyl-lead are measured. On addition of a complexing agent and using the latter plating potential, dimethyllead can be measured in the presence of inorganic lead. The HPLC method used for the separation of phenolic compounds is a modification of a previously described method. A comparison was made between a UV detector and an EC detector in series. In general, the EC detector offered lower limits of detection for most of the phenolic compounds studied. Analysis of beers indicated that EC detection was more suitable than UV detection with respect to sensitivity and selectivity.