My First PhD Paper is Published!
Last month, I was thrilled to see my first PhD paper, “Spatial and temporal (annual and decadal) trends of metal(loid) concentrations and loads in an acid mine drainage-affected river,” published in Science of the Total Environment.
The journey to publishing this paper wasn’t easy, but it’s so rewarding to finally share this work. This research investigates how contaminants from acid mine drainage (AMD) behave over space and time, using the Carnon River in the UK as a case study.
The Carnon River carries a legacy of contamination from centuries of mining. One of the most notorious sources of contamination is the County Adit—an underground gallery spanning over 60 km of historic mine workings. It’s considered one of the most contaminated water bodies in the UK, continuously discharging AMD into the river. Mining in the Carnon River catchment dates back to the Bronze Age and continued intermittently until 1991, when the Wheal Jane mine closed. This long history of mining has left a substantial impact on the river system.
What Did We Study?
Our research explored the sources, loads, and transport mechanisms of arsenic (As), copper (Cu), zinc (Zn), iron (Fe), and sulfur (S) in the Carnon River. To understand how contaminants behave in the Carnon River, we worked with two datasets:
- A detailed 12-month sampling campaign, capturing seasonal variations in riverine geochemistry and discharge
- 22 years of monitoring data collected by the Environment Agency (England), revealing long-term trends.
By analysing these datasets, we were able to examine how these contaminants behave as a function of space and time and how they impact both the river and the estuary where it meets the coast.
What Did We Find?
This study highlights the importance of monitoring AMD-affected rivers, as their behaviour can vary significantly over time and space. Such variability is critical to understanding their long-term environmental impacts, as these rivers can continue contaminating fluvial and coastal systems for decades or even centuries after mining has ceased.
Here are some key findings from the study:
- Legacy AMD discharges create long-term liabilities for receiving rivers.
- Over 22 years, As and Fe output to the coastal zone has increased, underscoring the lasting impacts and persistence of mining contamination.
- The release of Cu and Zn is closely linked to river discharge, while pH and redox conditions (Eh) influence the mobility of Fe, S, and As.
- The Carnon River’s output of metal(loid) to the estuary is comparable to other AMD-affected rivers globally.
- Diffuse sources, such as smaller discharges and runoff, play a significant role in contributing metal(loid)s to the river.
Why Does This Matter?
Understanding the behaviour of metal(loid) contaminants in AMD-affected rivers is essential for managing their long-term environmental impacts. These rivers don’t just impact their immediate surroundings—they can transport these contaminants to coastal environments, affecting ecosystems and communities far downstream. The insights gained from this study demonstrate the value of using both contemporary and historical datasets to capture the full picture of contamination dynamics.
A Picture Tells a Thousand Words
Below is a striking image of AMD from the County Adit meeting the Carnon River. It’s a vivid reminder of the ongoing challenges posed by legacy mining contamination.
Looking Ahead
This work underscores the need for continued monitoring and management of AMD-affected rivers to mitigate their impacts. While we can’t undo the mining legacy of the past, we can work towards better monitoring and mitigation of its impacts. How many other rivers around the world tell a similar story? As we learn more about these systems, we gain the information to develop the tools to protect ecosystems and communities from their impacts.
If you’re curious to dive deeper, check out the full paper in Science of the Total Environment (https://doi.org/10.1016/j.scitotenv.2025.178496). I hope it sparks as much interest in this field as I’ve felt throughout this journey!