Increased industrialization, population growth, growing urbanization, and overuse of natural resources are causing severe threats to the natural environment. Furthermore, the risk of contaminated drinking water in many regions of the world motivates the scientific researchers and technologists to develop advanced strategies and technologies for enhancing water quality, protection of long-term water resources, and sustaining the environment. Social communities are now focusing on eradication and removal of environmental contaminants, as environmental protection awareness programs are increasing gradually [[1], [2], [3], [4], [5]]. The environment and human health are seriously threatened by the uncontrolled and inadequately treated discharge of waste from various industries, such as the pharmaceutical, paper, textile, metal, paint, fertilizer, food, battery, and other sectors, as well as by several anthropogenic activities. In recent years, one of the main research hotspots has been the removal of hazardous contaminants from water. Typically, hazardous contaminants include antibiotics, heavy metal ions (HMIs), pesticides, pharmaceutical drugs, and phenolic compounds, which pose a serious threat to the human health and ecological environment owing to the possible biological and physiological toxicity [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14]]. When toxic chemicals are discharged into the environment, they pollute the atmosphere, damage human health, contaminate food supplies, and upset the balance of ecosystems. Agricultural and industrial sectors are discharging several pollutants into the surrounding environment, which are seriously contributing to the contamination of the environment. Heavy metal ions, pesticides, pharmaceuticals, and phenols are some of the important classes of environmental contaminants. Identifying chemical origins is one of the primary causes of detecting environmental contaminants [1,3,4,6,10,[15], [16], [17], [18]].

Significant interest has been exhibited in wastewater remediation, particularly in the degradation and removal of many types of hazardous contaminants, as well as very sensitive and selective monitoring of even trace amounts of these pollutants utilizing practical and environmentally friendly approaches. As a result, it is critical to detect dangerous chemicals even at low levels. With the increasing need for safe food and water, several traditional and conventional approaches have been created to meet the stringent environmental laws. These strategies are effective, however there are significant practical limits. Recent years have seen the development of numerous sensor-based techniques due to the apparent demand for quick and accurate assessment of a wide range of pollutants. In this context, significant emphasis has been dedicated to the design and construction of sensing technologies based on electrochemical methods of detection since they can offer multiple benefits such as portability, simplicity of use, comparatively affordable instruments, and quick response times [1,3,4,6,7,9,11,[14], [15], [16]]. Electrochemical sensors are regarded as appropriate tools for accurate identification of a wide range of analytes due to their portability, fast responsiveness, simplicity of design, and ability to detect target molecules specifically and sensitively in complicated sample matrices. Electrochemical sensing strategies have become progressively important in modern analytics owing to their ability to detect a wide range of substances precisely and efficiently. The creation of new electrochemical sensors with increased sensitivity, low limit of detection (LOD), and good selectivity is heavily dependent on specialized material selection, which is a crucial factor of sensor behavior [[1], [2], [3], [4],9,11,[15], [16], [17], [18], [19], [20]].

A sensor is a device that can determine various parameters and convert the reading results into accurate signals. The diversity, sensitivity, selectivity, accuracy, and stability of the data recorded are the most crucial parameters for sensors since they allow for appropriate environmental monitoring. Novel sensor device development with specific qualities, such as low cost, increased sensitivity, improved reliability, faster reaction, smaller size, simplified working principle, quick recovery, and on-the-spot assessment, has become more and more necessary [13,14,20]. A closer look into electrochemical sensors helps us better comprehend these useful tools that detect and analyze molecules of interest using electrochemistry and biological variables. Because of its many advantages and wide range of applications, electrochemical sensors have garnered a lot of attention. They detect electrical signals produced on the surface of electrode by chemical processes. A chemical or biochemical detection mechanism (the receptor) and a physicochemical converter that can transform the chemical or biochemical response into a quantifiable analyzing signal are the two functional units that typically make up these sensors. Over the past few years, several electroanalytical sensing systems have been developed for environmental pollutants detection. By capturing the output signals (such as current, potential, phase, charge, frequency, etc.) connected to chemical reactions that usually take place at the electrolyte-electrode interface, electrochemical sensing techniques make use of the connection between electricity and chemistry. Electrochemical techniques have been categorized into multiple approaches, including potentiometric, amperometric, voltametric, and coulometric procedures. Galvanostatic and potentiostatic methods are frequently employed among control modes of operation. Traditional electrochemical sensors have three components, a working electrode, counter electrode, and reference electrode. These electrochemical devices can create Faraday currents at various potentials, allowing for the simultaneous detection of several electroactive analytes. The interactions between these analytes and the transducer produce electrochemical impulses in the form of resistance, impedance, current, or potential [[1], [2], [3], [4],9,11,[15], [16], [17], [18], [19], [20]]. Furthermore, while some traditional remediation approaches, such as physical, chemical, or biological methods, have been reported to remove or detect or treat contaminants in real samples, they are insufficient to achieve the desired results for contaminant removal, detection, or treatment. As a result, transitioning to a more sustainable, cost-effective replacement is critical. In this context, outstanding performance nanomaterials have received a lot of interest. Nanotechnology is a field that can address the demand for technology that detects and break down contaminants at the atomic and molecular levels. Recent developments in nanomaterial science and technology have driven researchers to pave the path for building emerging cost-effective nanostructures to be used in various fields [[21], [22], [23], [24], [25], [26], [27], [28], [29], [30]]. Modification of the electrode using nanomaterials plays a crucial role in achieving effective detection. Direct electrochemical reduction is a promising technique for detecting pollutants. The application of electrode modifying materials is especially important. When nanoparticles are used to change the interface of the electrode, electrochemical sensor sensitivity improves dramatically, which is due to nanomaterials' excellent electrocatalytic capabilities and wide surface structures. Several reports have recently been published on sensors meant to detect pollutants using nanomaterial-modified electrodes. These sensors have characteristics that include ease of use, low cost, fast analysis, a large detecting range, and mobility. They allow rapid, precise, and sensitive detection of small quantities of the contaminants [29].

Electrochemical sensors are used widely to detect environmental contaminants, it is essential to develop materials with a specific recognition function and enhanced selectivity. Carbon-based nanomaterials have attracted considerable interest as progressive and potential electrochemical modifiers over the past few years due to their remarkable capabilities in electrochemical sensing applications. In addition to their elevated selectivity and sensitivity for identifying environmental pollutants, these materials have numerous significant advantages. Electrochemical sensors based on carbon-based nanomaterials are used in various scientific and technological fields, including energy management, biomedical, environmental pollutants recognition, biotechnology, and health care. It is vital to fabricate selective and sensitive electrochemical sensing platforms based on carbon-based nanomaterials to detect various environmental pollutants. In the recent years, substantial research advancements have been made in designing carbon-based materials to fabricate electrochemical sensing platforms for the detection of environmental contaminants. High-performing electrode materials play an important role in improving electrochemical sensor detecting capability. With the continuing development of nanotechnology, specifically the widespread application of innovative functional materials, it is crucial to broaden the scope of application and recognition range of environmental contaminants sensors. Fig. 1 shows the schematic illustration of the electrochemical sensor setup for the detection of environmental contaminants. Herein, we comprehensively reviewed and systematically analyzed the recent trends and advances of carbon-based nanomaterials for electrochemical sensing of environmental contaminants such as HMIs, phenolic compounds, drugs, and pesticides. Provided an overview of the emerging environmental contaminants. Synergistically discussed the significant roles of the carbon-based composite materials as the working electrode and modifier materials in the electrochemical sensing of environmental contaminants. Progress made in the carbon nanomaterials based electrochemical modifiers have substantially improved electrochemical performance of sensors for detecting the contaminants with notably low detection limits (pico to micro molar range), wide linear ranges, high stability, excellent selectivity, and appreciable sensitivities. Lastly, current challenges and potential research directions of electrochemical sensing of environmental pollutants employing carbon-based nanomaterials were outlined in conclusions and perspectives section. This work will be beneficial for the people dealing with the environmental contaminants detection and intending to enhance the electroanalytical performance or sensing of the trace levels of environmental contaminants detection in real samples.