In recent years there has been a rising interest in the environmental sector of natural sciences, as an increase in pollution in the environment has been observed. The industrial activity to sustain an ever-growing human population leads to the uncontrolled release of pollutants, e.g lead. As a result, rigorous limits have been set for the maximum allowed concentration for each pollutant in the environment. Since the content of pollutants occurring in natural ecosystems should be kept as low as possible, there is an ongoing search for analytical methods with ever-lower detection limits. For that, ion-selective electrodes (ISEs) are constantly investigated as they poses several desired properties for an environmental sensor. Namely, they are portable and relatively inexpensive and with maintenance limited to a minimum. The environmental analysis of ions requires the sensor to operate at low and ultra-low concentrations of analyte.  Thus, extending the sensitivity range of the ISEs by lowering the detection limit is required. In this presentation, the newest measurement protocols and application of ISEs for lowering the detection limit and measurements of ionic pollutants in natural waters will be discussed.