Scientists have assembled a remarkable record of water value in the Thames that stretches reverse larger than 140 days. Over the 140 years of the new time series, this nitrogen part of river chemistry is seen to climb persistently. The contamination will almost positively have distorted the biology of the river, irregular the balance of plant life in the Thames.
Obviously visible in the new time series are major land-use changes during the 20th Century that gave vast nitrate kicks to the hydrology of the Thames sink. Ploughing fields opens up organic matter to corrosion and the release of nitrogen held in the soils. This will ultimately wash throughout to the river, as will nitrogen practical to those fields in the form of fertilizers.