Pollutant Monitoring Solutions in Water and Sewerage Networks: A Scoping Review

Ensuring water quality standards in water and wastewater distribution systems is crucial to protect public health and ecosystems. Environmental monitoring technologies have evolved rapidly owing to the use of portable devices and digital platforms. The integration of digital sensors, Internet of Things (IoT) systems, and technologies such as Arduino and Raspberry Pi enables real-time monitoring of emerging contaminants (CECs) in water and wastewater networks, overcoming the limitations of traditional methods. This review provides an overview of integrated systems based on lab-on-a-chip, Raman spectrometry, and colourimetry for pollutant detection in water and wastewater networks. Our comparative analysis highlights that lab-on-a-chip devices enhance analytical efficiency (achieving detection limits in the sub-ppb range for certain heavy metals), Raman spectrometry—especially SERS—provides ultra-trace sensitivity and molecular specificity, and colorimetric sensors offer cost-effective, rapid field deployment albeit with moderate sensitivity. The novelty of this work lies in integrating these findings to illustrate how IoT-enabled sensor platforms can complement traditional methods for real-time water quality monitoring. The PRISMA framework and Rayyan platform were used for systematic literature selection, analysing 72 recent references. These findings indicate that lab-on-a-chip systems enhance analytical efficiency but face selectivity and reagent stability challenges. Raman spectrometry offers high specificity but has high operational costs, while colorimetric sensors are practical for rapid field analysis. Future research should focus on optimising analytical protocols and validating them in real-world settings, as suggested by recent studies monitoring specific contaminants in different aquatic matrices.