Lord de Mauley (Whip, House of Lords; Conservative) replied that:
"Forty-one per cent of river water bodies and 64 per cent of lakes in England and Wales assessed under the Water Framework Directive (WFD) currently fail to meet the phosphate standards for good ecological status. This is based on WFD classification data for the period 2006-08 and was used for the River Basin Management Plans, published in 2009. The main reasons for failure of the phosphate standards are sewage effluent discharges and run-off from agricultural land. There are standards for over 50 other water quality parameters in freshwaters and the sources of pollution causing failures."
We're running out of freshwater and the freshwater that we have is polluted! Agriculture accounts for around 61% of the nitrate in rivers (ADAS report to Defra 2007) and around 26% of phosphates (White and Hammond report to Defra 2006).