Cadmium (Cd) contamination in water and soil is a significant environmental concern exacerbated by crop uptake and bioaccumulation of Cd. Monitoring Cd levels in the environment is crucial to minimize human exposure and associated health risks. In this context, we have developed a novel method for synthesizing cadmium complex nanoparticles, which offers an environmentally sustainable and reliable approach with potential applications in various fields. This research presents an advanced Nano cadmium complex sensor to detect cadmium ions. The Nano cadmium complex was comprehensively characterized using multiple analytical techniques, including Dynamic Light Scattering (DLS), Zeta potential analysis, Atomic Force Microscopy (AFM), Fourier-Transform Infrared (FT-IR) spectroscopy, contact angle measurements, BET surface area determination, and pore size analysis. We explored the potential of the Nano cadmium complex as a Quartz Crystal Microbalance (QCM) sensor, chosen for its simplicity, cost-effectiveness, and high sensitivity, focusing on rapid cadmium detection. The developed Nano cadmium complex based-QCM sensor demonstrates high selectivity and sensitivity, capable of detecting cadmium at concentrations as low as 0.1 ppm. We evaluated the sensor's performance in identifying cadmium ions under varying pH levels and temperatures. Additionally, we assessed the cytotoxic effects of the cadmium complex nanoparticles. This method effectively detects Cd [II] ions in groundwater and industrial effluent wastewater samples, serving as a valuable environmental monitoring and protection tool. The research contributes to developing sensitive and specific sensors for heavy metal detection, addressing the critical need for efficient environmental contaminant monitoring systems.