New Research Highlights Threat from Pollutants in Rivers Test & Itchen

Pollutants in Test Itchen Rivers

Portsmouth University Research Paper on Polar Organic Contaminants in the Rivers Test and Itchen

This article provides an overview of the research led by Portsmouth University into the level of pollution by polar organic contaminants in the Test & Itchen. The Test and Itchen Association part funded this vital research with a grant of £3450. 

Researchers deployed Chemcatcher passive samplers across these rivers to quantify these contaminants and assess the risks they pose to the aquatic environment. These samples were then analyzed using mass spectrometry techniques and some statistical weighting to give time and spatial trends.    

The study underscores the urgent need for concerted efforts to mitigate the impact of polar organic contaminants on the Rivers Test and Itchen.

Full text of the Research

What are Polar Organic Contaminants?

Polar organic contaminants are chemicals that have polar molecular structures, meaning they have regions with positive and negative charges. These chemicals are often water-soluble and can easily enter aquatic environments through various pathways, including agricultural runoff, wastewater discharge, and industrial processes. Common examples include pharmaceuticals, personal care products, pesticides, and herbicides. Because of their polarity, these contaminants can persist in water bodies and pose risks to aquatic life, leading to potential ecological and health impacts.

Highlights & Key Findings

  • Researchers targeted 121 compounds which could be  quantified using the sampling technique
  • Waste water treatment plant effluents were the main contributor of pharmaceuticals
  • Five compounds were found at or above their predicted no effect concentrations
  • Presence of imidacloprid could impact macroinvertebrate communities

Extent of Contamination

Over a year-long study, 121 polar organic compounds were identified and quantified across 17 sites along the rivers. The study found that wastewater treatment plants (WWTPs) were the primary source of these pollutants, with significant contributions from agricultural runoff and urban activities. Notably, the River Test exhibited higher concentrations and a greater diversity of contaminants compared to the River Itchen.

The presence of several pharmaceuticals, including antidepressants like venlafaxine and antibiotics such as sulfamethoxazole, was consistent across seasons, highlighting their continuous discharge into the rivers. The study also detected the insecticide imidacloprid, which poses a significant risk to macroinvertebrate communities.

Five contaminants exceeded their predicted no-effect concentrations (PNECs), indicating potential ecotoxicological impacts.

  •   2-hydroxy-terbuthylkazes – a herbicide/biocide used to treat cladding on buildings.
  •  Alprazolam – anxiety drug – a designer drug.
  •  Azithromycin – antibiotic for humans and animals.
  •  Diclofenac – pain killer – harmful to reproductive function in fish.
  •  Imidaclopid – dog flea treatment – harms all invertebrates.

Venlafaxine also exceeded the EU Watch list concentration – it is a veterinary and human tranquilizer. 

Among these, the presence of imidacloprid, even in low concentrations, raised alarms due to its harmful effects on aquatic life. The study also noted the persistence of banned herbicides like atrazine and simazine, which continue to enter the rivers through groundwater.

Pollutants threaten River Test

Temporal and Spatial Variations

The study revealed significant temporal and spatial variations in contaminant concentrations. Seasonal trends indicated higher levels of certain pollutants, such as herbicides, during autumn and winter, corresponding to their application periods in agriculture. In contrast, pharmaceuticals showed more consistent presence throughout the year.

Spatially, sites downstream of WWTPs consistently showed higher contaminant levels, underscoring the need for improved treatment processes to reduce the discharge of these harmful substances. The River Test, in particular, displayed greater pollutant loads, likely due to its larger number of WWTPs and agricultural activities within its catchment area.

Environmental and Ecological Implications 

The study’s findings highlight the complex mixture of pollutants present in our chalk streams, raising concerns about their cumulative effects on aquatic ecosystems. The detected contaminants have been linked to various adverse effects, including endocrine disruption, behavioral changes in aquatic organisms, and reduced biodiversity. The presence of imidacloprid, in particular, could lead to declines in macroinvertebrate populations, which are crucial for the health of these rivers.

T&I Comment on the Research

The findings are not a surprise as there is a growing scientific consensus that these chemicals are causing significant harm in the environment.  They underscore the reason that all rivers in the UK are failing the Water Framework Directive score for chemical health.  It is most probably safe to say there is a direct correlation between chemical health and the poor ecological score for UK rivers. All too often the government and regulators have not taken this threat to our rivers seriously enough.  The past loop holes allowing neonicotinoid to be used despite bans in Europe are just such an example.  

Recommendations for Action

It is clear that human life has become dependent on some of these chemicals.  Until such time as alternatives can be found, then we are going to have to face the cost of cleaning up our act.  So we think the following recommendations are a good start point.

Given the findings, several recommendations have been proposed to protect the Rivers Test and Itchen:

  1. Banning of the most dangerous chemicals: unless there is no alternative to protect human health, then ban the chemicals found to be harmful to the environment. We support The Rivers Trust’s call for an immediate ban on Imidacloprid.
  2. Agricultural Practices: Reducing the use of harmful pesticides and herbicides, particularly those that are persistent in the environment, is crucial. Promoting organic farming practices and implementing buffer zones along riverbanks can help minimize agricultural runoff.
  3. Regular Monitoring: Continuous monitoring using passive sampling techniques like Chemcatcher should be implemented to track pollutant levels and identify sources of contamination. This will enable timely interventions to protect these sensitive ecosystems.
  4. Improved Wastewater Treatment: Urgent research funding and policy commitment to upgrading WWTPs to better remove dangerous chemical polar organic contaminants, particularly pharmaceuticals and human care products, is essential. This could include advanced treatment technologies like activated carbon filtration or ozonation.
  5. Public Awareness and Policy Advocacy: Raising awareness among local communities, policymakers, and stakeholders about the risks posed by these contaminants is vital. Stronger regulations and enforcement are needed to control the use of hazardous chemicals and ensure the protection of these rivers.

Water quality monitoring River Test

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