Causes of pol­lu­tion

Countryfile Magazine - - Fishermen’s Jumpers -

SLURRY FROM COW HERDS

Causes in­clude over­flow­ing stores, con­tam­i­nated drains, bro­ken seals, burst sluices and gen­eral mis­man­age­ment of slurry spread­ing around sur­face wa­ters. Huwel Man­ley at Nat­u­ral Re­sources Wales says the in­ten­si­fi­ca­tion of dairy herds – prompted by spikes in milk prices – has made mat­ters worse, with more cat­tle pro­duc­ing more slurry that must be stored in in­fras­truc­ture that has not been en­larged or up­dated to hold it. “Slurry is very dam­ag­ing, it’s quickly bro­ken down by bac­te­ria and spreads phos­phates in rivers and dam­ages the ecology,” says An­gling Trust’s Mark Lloyd. “The good farm­ers are as frus­trated as we are. Oth­ers are strug­gling, they would like to do the right thing but face big cap­i­tal in­vest­ments.”

PES­TI­CIDES AND POUL­TRY POO

Dur­ing wet weather, these can be washed into rivers. High lev­els of phos­phates and ni­trates cre­ate al­gae that smoth­ers river beds. Free-range poul­try is an in­creas­ing prob­lem – chick­ens com­pact the grass on which they for­age, hard­en­ing the sur­face. Their fae­ces, con­tain­ing high lev­els of phos­phates, is eas­ily washed away by rain.

Pes­ti­cides cause prob­lems for wa­ter com­pa­nies. Dr Jodie Ret­tino at Sev­ern Trent Wa­ter says: “We shut down works on a num­ber of oc­ca­sions be­cause pes­ti­cides get into reservoirs. If we get three or four pes­ti­cides at a high peak, our treat­ment pro­cesses don’t work so well. Clean-up costs at a sin­gle wa­ter treat­ment works for pes­ti­cides can be around £4m a year.”

SED­I­MENT

Top­soil can be washed off land into rivers dur­ing bad weather. Plough­ing of grass­lands and the in­ap­pro­pri­ate choice and po­si­tion­ing of crops, such as maize (which has risen from 8,000ha to 180,000ha in just 10 years) and potatoes is a sig­nif­i­cant cause, along with poor drainage. In­ap­pro­pri­ate crop plant­ing in up­land ar­eas – maize, wheat and stub­ble turnip on steep slopes – has caused land­slips that clog up river cour­ses. Over­graz­ing by sheep on hills also leads to soil be­ing washed away. “The soil smoth­ers the gravel on the river bed and fills the gaps be­tween stones where fish lay their eggs,” says An­gling Trust’s Mark Lloyd. “That also stops eggs of all kinds of in­sects hatch­ing.”

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