A collaborative study by WRc and Queen Mary University of London has delivered new insight into the occurrence and seasonal behaviour of microplastics in UK freshwater systems. Through a multi-season monitoring programme across the River Avon, the project established a high-resolution, polymer-specific approach to microplastics assessment.
The work provides water companies and environmental stakeholders with a clearer understanding of how microplastics vary across locations and time, supporting evidence generation for AMP8 and emerging regulatory frameworks, and enabling more informed environmental management and planning.
Microplastics are now widely recognised as a persistent contaminant in freshwater environments, attracting increasing attention from regulators, policymakers, and the public. However, progress in managing this issue has been constrained by a lack of structured, comparable datasets, particularly within UK rivers.
Freshwater systems act as key transport pathways, receiving inputs from wastewater treatment works, urban runoff, and wider catchment activities. Yet much of the existing evidence is limited in resolution, often lacking seasonal coverage or detailed material characterisation.
To address this, WRc and Queen Mary University of London undertook a 10-month, multi-season study across three River Avon sites: Malmesbury, Chippenham, and Bath; applying high-resolution analytical techniques alongside contamination-controlled sampling to generate reliable, comparable monitoring data. A complementary laboratory study also explored interactions between selected microplastics and human cells to provide early insights into potential health relevance.
A major barrier to effective microplastics management is not the detection of particles, but the lack of actionable insight derived from monitoring data. Current approaches often fail to capture how microplastics behave across systems, limiting understanding of source contributions, transport pathways, and environmental significance.
This is further complicated by inconsistencies in analytical methods and reporting formats, making it difficult to compare results across studies or build a coherent evidence base. For water companies, this creates uncertainty in assessing treatment performance, identifying priority areas, and responding to increasing regulatory and public expectations.
As requirements under AMP8 and WINEP evolve, there is a growing need for monitoring approaches that deliver consistent, high-quality data that can support interpretation, prioritisation, and decision-making, even in the absence of formal regulatory thresholds.
To address these challenges, the study applied a structured, multi-season monitoring framework supported by Laser Direct Infrared (LDIR) spectroscopy, enabling rapid, particle-level identification of microplastics. This approach provided detailed information on polymer type, particle size, and morphology, capturing a level of resolution not typically achieved in routine monitoring.
Sampling was conducted across three representative river locations and seasons using ISO-informed, contamination-controlled protocols, ensuring consistency and comparability across datasets.
Crucially, the study moved beyond simple particle counting by incorporating polymer-resolved analysis and contextual interpretation, allowing clearer insight into variability across sites and conditions. This enabled the identification of patterns and areas of elevated concern, demonstrating how monitoring data can be translated into meaningful environmental intelligence.
The study produced a multi-season, polymer-resolved dataset for microplastics across the River Avon, highlighting clear spatial and seasonal trends. Microplastics were detected at all sites, with concentrations highest in winter and lowest in autumn, reflecting the influence of hydrological conditions.
Malmesbury (upstream) showed consistently higher levels, while Bath (downstream) recorded lower concentrations, indicating the role of catchment characteristics and treatment influences.
Nine polymer types were identified, dominated by polyamide (PA) and polytetrafluoroethylene (PTFE), with the majority of particles occurring as small fragments (<50 µm). These characteristics are important as smaller particles are more likely to interact with aquatic organisms and move through treatment systems.
Screening-level interpretation of the data indicated periods and locations of elevated environmental concern, particularly during higher-flow winter conditions, providing a practical basis for prioritising further monitoring and investigation, and supporting environmental decision-making.
The study provides a practical demonstration of how microplastics monitoring can evolve from fragmented data collection to structured, decision-relevant evidence generation. By revealing clear spatial and seasonal patterns across a UK river catchment, the work supports more targeted investigation and improved understanding of environmental pressures.
Importantly, the findings highlight how high-resolution data can inform treatment evaluation, catchment management, and regulatory engagement, helping organisations prepare for increasing scrutiny under AMP8 and future policy development.
Building on this success, the methodology has been translated into WRc’s Microplastics Analytical Platform (MAP), a scalable framework for consistent monitoring, interpretation, and reporting across water systems. MAP provides a pathway for organisations to move from uncertainty to proactive, evidence-based management of microplastics in line with evolving regulatory and societal expectations.