The contamination of water by heavy metals is a danger to both mankind and nature. The presence of heavy metals, including zinc, copper and nickel, above certain limits can lead to massive biological and ecological destruction. Traditional, laboratory-based methods of detecting heavy metals are accurate but expensive and take too long, so they are not suited for real-time monitoring. This paper describes a low-cost, Internet of Things (IoT) enabled heavy metal detection system that uses a TCS3200 colour sensor in conjunction with selective chemical reagents. The sensors indirectly detect the presence of zinc sulphate (ZnSO₄), copper chloride (CuCl₂) and nickel sulphate (NiSO₄) through the comparison of reagent-induced colour changes (i.e., colourimetric). The sensor data is processed by an ESP32 microcontroller, which communicates with the ThingSpeak Cloud for real-time monitoring and visualisation. The results of experiments show that the proposed system is reliable for the detection of metals based on colour intensity differences and can be used for both academic and preliminary field work validation.
M et al. (Sat,) studied this question.