Health of UK Rivers – Water Quality and Ecology

Professor Gary R. Fones discusses the arguments for improving river water quality, focusing on the health of UK rivers.

Professor of Environmental Aquatic Chemistry.
Fellow of the Royal Society of Chemistry.
Chartered Environmentalist (CEnv).
Core member of the NERC Peer Review College.
Research interests include water and sediment quality monitoring using in-situ passive samplers for trace metals, nutrients, and polar organic contaminants.
Studies the impacts of pollution on river water quality and ecology.
Works closely with several UK water supply companies on integrating passive sampling monitoring into their river catchment management strategies.

Healthy rivers play a crucial role in mitigating climate change.
Rivers protect communities from flood and drought events and enhance ecosystem and biodiversity resilience.
Most UK and Ireland rivers are not in a healthy state.

Almost all land-based activities impact rivers.
Rivers reflect the chemical and physical characteristics of their local catchments.
Rivers have been polluted, channelized, and fragmented.
Their condition reflects centuries of catchment activities.

Obvious pollutants include plastic bottles, crisp packets, single-use vapes, and wet wipes.
Murky soil and grey wastewater from combined sewage overflows (CSOs) are also visible pollutants.
Clear waters can still contain microplastics, industrial chemicals, hydrocarbons, fertilizers, pesticides, and pharmaceuticals.
Untreated sewage and treated wastewater (containing pharmaceuticals, pesticides from flea treatments, nutrients, and household cleaning products) pollute rivers.

The Environment Agency assesses water chemistry and other health measures under the WFD.
Rivers are divided into shorter stretches called river waterbodies to monitor health changes along their length.
Headwaters are often healthier than downstream stretches due to cumulative pollution.
River health is measured by combining chemical and ecological status.

Chemical health is determined by the presence or absence of chemical pollutants through water sampling.
Ecological health considers the living organisms in the river and the degree of modification.
The presence, absence, and abundance of species indicate general river health.
Ecological health assessment includes:
- Hydromorphology
- Physico-chemical elements
- Biological elements (fish, macro-invertebrates, macrophytes, and diatoms)

Main sectors impacting rivers:
1. Agriculture and rural land management (62%)
2. Water industry (54%)
3. Urban and transport (26%)
Activities causing failure:
1. Poor nutrient management (fertilizer) (34%)
2. Continuous sewage discharge (36%)
3. Poor livestock management (25%)
4. Poor soil management (16%)
5. Barriers (13%)
6. Urbanization (11%)
7. Intermittent sewage discharge (11%)
8. Private sewage treatment (8%)
9. Groundwater abstraction (6%)
10. Transport drainage (5%)
11. Land drainage (5%)
12. Industry discharge (4%)
13. Misconnections (4%)
14. Farm Infrastructure (4%)
15. Flood protection (3%)
16. Invasive non-native species (3%)
17. Mining (3%)
18. Drought (3%)
19. Septic tanks (2%)
20. Contaminated land (2%)

In 2022, the Environment Agency assigned a 'Does not require assessment' status to all river stretches for chemical health.
In 2019, all rivers assessed failed chemical health standards due to uPBTs (ubiquitous, persistent, bioaccumulative, and toxic chemicals).
Examples of uPBTs:
- Mercury (now banned).
- Brominated diphenyl ethers (pBDE).
- Tributyltin (now banned).
- Polyaromatic hydrocarbons (PAHs).
Emerging pollutants include pharmaceuticals, fungicides, and pesticides used on pets.
Chemicals can persist for decades.
Perfluorooctane sulfonic acid (PFOS) levels in freshwater fish in England are, on average, over 300 times the safe level for aquatic life, despite being banned 15 years ago.
Per- and poly-fluoroalkyl substances (PFAS) are a group of chemicals known as ‘forever chemicals’.

Focus on organic contaminants (polar and non-polar) or 'emerging substances'.
Examples include pharmaceuticals, personal care products, polar pesticides, degradation products, biocides, and flame retardants (PFAS).
These substances are often not included in routine monitoring.
Infrequent spot sampling can miss these contaminants.
Passive sampling is suggested as an alternative.

Pesticides and pharmaceuticals can have adverse effects on human health, including:
- Carcinogenic effects
- Cytotoxic effects
- Genotoxic effects
- Effects on the immune, respiratory, reproduction, cardiovascular, and central nervous systems

Point Source Pollution: Water pollution from a single, discrete place, such as a pipe.
Diffuse Pollution: Pollution from widespread activities, such as runoff from farmlands, forests, roads, and construction sites. Includes nutrients, pesticides, chemicals, manure, and sediments.

Recent research focuses on the River Itchen and River Test.
121 compounds quantified in the Test and Itchen.
Toxicity (PNEC) identified for:
- Imidacloprid and 2-hydroxy-terbuthylazine
- Azithromycin, diclofenac, and alprazolam
- Venlafaxine and o-desmethylvenlafaxine
- Caffeine
These compounds have a detrimental impact on ecosystems and fly life.

2021 had lower mean diversity of mayfly, stonefly, and caddisfly species (EPT) compared to the original Riverfly Census.
EPT (Ephemeroptera, Plecoptera, and Trichoptera) are aquatic invertebrates.
20 or more EPT species in a sample indicate high water quality.
Chalkstreams have lost an average of 41% of mayfly species compared to 1998 values.
75% of sediment pollution in English rivers comes from agricultural activities.
26,200 tonnes of phosphorus are lost into the aquatic environment each year.
Over 350,000 chemicals and mixtures of chemicals are registered for production and use.

What is being done to improve UK river water quality?
- 25-year plan.
- Environment Act.
- Water quality in rivers reports.