A Review of Recent Advances in Microplastic Research and ROVs to Aid the Development of an Integrated Solution for Microplastic Pollution

Abstract

Microplastic pollution poses a critical threat to aquatic ecosystems, especially marine ecosystems along with freshwater ecosystems, as these infiltrate food chains and disrupt aquatic life. Despite ongoing efforts to mitigate this issue, the complexity of microplastic detection and filtration in underwater environments presents several challenges, including the limitations of current filtration technologies and the lack of efficient, low-cost identification systems. This review synthesizes recent research on key technologies and methodologies for addressing these challenges, including habitat monitoring with robotic systems, microplastic filtration using various principles, and underwater acoustic network synchronization to enhance data collection. Additionally, this study explores emerging techniques for optical detection of microplastics and methods for assessing microplastic distribution at varying depths. Gaps in the existing literature, particularly in the areas of biodegradation and real-time detection, are highlighted. By integrating findings from these diverse fields, this paper aims to serve as a starting point for a combined system that utilizes filtration techniques, deep-learning detection algorithms, and synchronized communication networks to improve the efficiency of microplastic identification and removal in aquatic environments.

Introduction

Microplastic Pollution and Its Impacts:
Microplastics—plastic particles smaller than 5 mm—are increasingly contaminating aquatic ecosystems, posing serious threats to marine life and human health. Originating from degraded larger plastics or microbeads in products, these particles are persistent in the environment, carrying toxic chemicals and accumulating in the food chain. Around 5.25 trillion microplastics are estimated to be circulating in the oceans, mostly from land-based sources.

Marine organisms often ingest microplastics, which can cause organ damage and spread through the food web. Humans are exposed via seafood, bottled water, and sea salt. Microplastics can carry harmful pollutants like PCBs and BPA, potentially leading to endocrine disruption, cancer, and other health issues. Freshwater systems are also affected, acting as conduits for pollution into marine environments.

Detection and Monitoring Technologies:
Traditional detection methods (e.g., FTIR, Raman spectroscopy, and density separation) are accurate but slow and labor-intensive. Advances include AI-based systems like YOLOv5 with DeepSORT, achieving up to 97% accuracy in real-time microplastic tracking. Portable sensors using infrared detection and energy-efficient underwater robots offer scalable, real-time monitoring capabilities.

Multimodal smart sensors and standardized indices (like MPPLI and MPCF) enhance accuracy and facilitate comparative assessments. However, environmental variability and limitations in detecting very small particles (under 1 mm) remain major challenges. Future progress requires improved AI adaptability and integration of detection systems with pollution indices.

Removal Techniques:

1. Filtration Systems:

   • Membrane Bioreactors (MBRs), Ultrafiltration (UF), and Reverse Osmosis (RO) can remove up to 99.9% of microplastics.

   • Dynamic Membranes (DMs) offer fast and efficient filtration in wastewater treatment.

2. Hybrid Technologies:

   • Combine physical and chemical methods (e.g., coagulation, electrocoagulation, photo-Fenton reactions) for improved removal of small particles.

   • Hybrid MBR systems consistently show the highest removal efficiency.

3. Biological & Green Methods:

   • Use algae and bacteria for biosorption and biodegradation.

   • Though slower, these methods are sustainable and can be integrated with filtration systems for long-term solutions.

4. Chemical Treatments:

   • Include advanced oxidation processes (e.g., Fenton reactions) and coagulation-flocculation to aggregate and break down microplastics.

Challenges include difficulty capturing very small particles, high costs, and energy demands. Future directions focus on optimizing hybrid systems, developing recyclable and bio-based membranes, and improving scalability.

ROV (Remotely Operated Vehicle) Technologies:
ROVs are vital tools for underwater microplastic detection and sampling. Key design features include:

• Structural durability and waterproofing for deep-sea conditions.

• Brushless motor propulsion for 6-DOF mobility.

• Raspberry Pi and ROS-based control systems for real-time video, sensor integration, and navigation.

• Acoustic communication systems ensure reliable data transmission underwater.

• Application-specific tools, like robotic arms or sediment samplers, allow precise environmental assessments, such as collecting seabed samples with minimal disturbance.

Conclusion

The widespread presence of microplastics in aquatic environments presents a multifaceted threat that extends beyond ecological disruption, with implications for public health and global environmental sustainability. This review has critically examined current methods for the detection, monitoring, and removal of microplastics, while also exploring the technological advances in ROV design and underwater communication systems that support these efforts. Advances in detection, particularly real-time monitoring technologies, have improved our capacity to track microplastics, but significant challenges remain, especially in detecting smaller particles and addressing the limitations posed by environmental conditions. Similarly, while filtration and hybrid treatment systems show considerable promise for microplastic removal, issues of scalability and operational cost continue to hinder widespread implementation. The use of ROVs has expanded our ability to conduct underwater research and environmental monitoring in challenging environments, while new developments in underwater communication technologies have enhanced the transmission of data necessary for effective control and analysis. However, the next phase of research must focus on integrating these approaches to create more robust, energy-efficient, and scalable solutions. Future innovations should concentrate on developing hybrid systems that combine the strengths of various detection, removal, and monitoring methods, while ensuring cost-effectiveness and operational efficiency. By addressing these key challenges, future work can pave the way for more comprehensive strategies to mitigate the global issue of microplastic pollution, protecting both aquatic ecosystems and human health.

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Copyright

Copyright © 2025 Abdul Ahad Khan, Ajinkya Paralkar, Arya Joshi, Himanshu Bhiwapurkar, Umesh Carpenter. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.