Chemical pollution is harming wild fish
Chemical pollution is one of the main causes of degradation and biodiversity loss in aquatic ecosystems.
But why are chemicals such a problem for salmon, trout and their waters?
More than 300,000 inventoried/regulated chemicals are currently used in industry, household and agriculture - which ultimately end up in our waters.
While European water bodies are contaminated with complex mixtures of ten thousands of chemicals, chemical status is defined on the basis of only 45 substances.
Concentrations of chemicals in the water may not reflect the true burden on river life, as chemicals may accumulate in tissues and be passed up the food chain.
Chemicals can harm river life lethally, where exposure causes direct death, and/or sublethally, where physiological pathways and natural behaviours are disrupted.
Where does chemical pollution come from?
The composition of chemical inputs differs according to types of land use around river catchments...
Agriculture, industrial activities and human conurbations all contribute different chemical mixtures to rivers.
Chemical inputs to rivers can be from diffuse sources, such as pesticide run off from farmland.
Chemical inputs to rivers can also be from point sources, such as pharmaceuticals from waste water effluent.
What are we doing to tackle chemical pollution?
Current monitoring* covers only a tiny fraction of the chemicals entering our waterways, extensively ignoring biological impacts and ‘cocktail’ mixture effects.
SPEAR is a way of calculating chemical impact on rivers by looking at the presence and absence of water invertebrate species.
Currently SPEAR is not used in the UK, but proposed boundaries to incorporate it into Water Framework Directive calculations do exist.
Using our data, we are encouraging the use of SPEAR nationally in monitoring our watery places for chemicals.
*of priority substance-based chemical status according to the Water Framework Directive (WFD)
We have put together a case study on the River Wensum to demonstrate the value of using invertebrates to better understand chemical pressures on UK waters. SPEAR values derived from our Riverfly Census species-level monitoring and chemical spot samples from WFD Watch List monitoring on the River Wensum were compared.
Despite all the chemicals being within their Environmental Quality Standard Targets in 2016, the invertebrate communities in the upper Wensum catchment showed consistent chemical pressure from 2015-2017.
This highlights that current monitoring is not reflecting the true impact of chemicals in our rivers.
We believe that businesses should not be allowed to damage the environment- they should return water in at least the same state as they receive it.
Across our campaigns, we have many examples of historic discharge permits, for businesses still operating today, that are not fit for purpose.
You can browse our news articles below to find out more about our work in this area.
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