Maria Staines

Maria Staines


I am extremely passionate about researching aquatic pollution from wastewater treatment storm overflow discharge. I graduated with a Distinction in MRes Environmental Science (2020) and a First Class in BSc (Hons) Environmental Science (2019), both from the University of Portsmouth. My MRes thesis was titled “Assessing nutrient pollution by wastewater treatment storm overflow discharge in Langstone Harbour estuary and the River Thames catchment, UK”. Through this project, I developed a keen interest in Catchment Science and observed the sources, pathways, contamination, and ecotoxicological consequences of nutrient pollution, with focus on storm overflow discharges.

This project was designed to determine whether, and to what extent, storm overflow discharge events cause nutrient pollution, and to highlight its importance in the aquatic environments. The goals of this study were to determine the short-term variability of nutrients in the context of high nutrient loads, and to examine the impact of storm overflow discharge events. From my results, it became clear that the untreated sewage in storm overflow discharges likely caused the fluctuating nutrient concentrations near the storm outfalls.

After graduating from my MRes, I worked as a Science Graduate for 2 years at Thames Water where I managed various projects. This includes monitoring and interpreting storm overflow discharge data and managing the Unconsented Combined Sewer Overflow (CSO) programme. My varied roles not only gave me the opportunity to become well-rounded in the water industry, but also to develop strong data management and interpretation skills.


It is from my industry experience and MRes project that I have found the excitement to explore the potential hotspot of riverine plastic pollution by CSO discharges.

Maria Staines

PhD title: “Combined Sewer Overflows: A Hotspot for Riverine Plastic Pollution?” – a CASE partnership with Anglian Water

Project Background

Tackling the global challenge of plastic pollution is at the forefront of current scientific research efforts. Nevertheless, research to date has focused upon the marine environment and there remains major gaps in our understanding of the origin, transport and fate of plastics in river systems, hindering our ability to evaluate the ecotoxicological consequences upon freshwater ecosystems. CSOs are potentially important hotspots for riverine microplastic and endocrine disrupting plasticiser pollution through the release of untreated, or partially treated, sewage effluent from wastewater treatment works (WWTWs). Concerns posed by CSOs are highlighted in the new Environment Act 2021 and this PhD project will seek to address fundamental questions regarding the nature and impact of microplastic and plasticiser material being released from CSOs.

Research methodology

Focusing upon a targeted selection of Anglian Water WWTWs encompassing a range of contrasting treatment systems, this project will integrate hydrological and analytical sciences to develop a novel quantitative evidence base on plastic pollution in riverine environments impacted by CSO discharge. Through an extensive field and laboratory campaign, I will first gather evidence on the abundance and composition of microplastics and plasticisers in water and sediments upstream and downstream of CSOs, before developing a scalable and transferable mapping tool to identify the concentration and loading of microplastics and plasticisers from CSOs into rivers across the wider Anglian Water region.

Awards and prizes

Awarded the Master’s Scholarship from the University of Portsmouth (£3000) for academic excellence.

Other information

Science Graduate at Thames Water (2020-22)

Gained an insight into the inner workings of the water industry through various roles:

  • Environmental Permitting & Regulations Specialist

Managed surveys and used GIS skills to interpret qualitative and quantitative water quality data for 71 unconsented CSO sites, which require new environmental discharge permits. Also, led the environmental permitting Compliance Assessment Summary of 364 sewage treatment works, which was presented to the Executive Board.

  • Water Quality Transformation Scientist

Liaised with the regulator to address complex catchment challenges for drinking water treatment works and managed the water quality improvement projects. Additionally, planned, implemented, and project managed the microbiological trial for rapid coliform enumeration.

  • Flow & Event Duration Monitoring Scientist

Responsible for analysis and graphical presentation of extensive flow and storm overflow (including CSO) discharge event duration datasets. Interpreted this data to determine environmental compliance of sewage treatment works.