This article gives a review of the analytical and environmental criteria which must be considered and the relevant specific developments needed for direct, reliable voltammetric measurements of trace metal speciation in environmental systems. In particular, this article will focus on the tools which enable remote, long-term in situ measurements. The development of such tools is a challenging task. The strategies that can be used to achieve this goal are described for the development of innovative and versatile gel-integrated voltammetric microsensors, micro-/mini-integrated analytical systems, and submersible probes. The advantages of these new tools with respect to selectivity, sensitivity, reliability, spatial and temporal resolution of data, and thus efficient environmental monitoring of the biogeochemical cycle of trace metals are demonstrated by providing examples of measurements made in various aquatic samples in laboratory (water, soils, solid-liquid interface) and in situ in fresh and seawaters.