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The River Thames Has a Drug Problem

As London’s urban population continues to grow, improper wastewater management increases exponentially. Every major and growing city has experienced at one point or another an imminent need to update its sewer systems in order to accommodate the waste influx. In London, this issue is acutely prominent due to improper disposal of sanitary products and the widespread use of pharmaceutical and recreational drugs. Particularly, a 2019 study out of King’s College London (KCL) found traceable quantities of cocaine in the River Thames.

The KCL research team studied the effects of cocaine and other sewage pollutants on the Thames’ marine wildlife. Some wildlife experts believed the cocaine found by the KCL team would cause marine life to exhibit a “high” somewhat similar to that experienced by humans. However, the KCL scientists stated there wasn’t enough cocaine in the river to actually induce such a reaction. In a similar study on the effects of cocaine-polluted water on eels, Italian researchers injected large quantities of cocaine into a study tank, resulting in the eels exhibiting a hyperactive reaction. The Italian eels were exposed to a much higher level of cocaine compared to those found in London. However, if the city continues down a path of high cocaine usage, the Thames could see cocaine quantities comparable to those utilized in the Italian eel study. In total, London citizens use around twenty-three kilograms of cocaine each day. This equates to 567,445 doses daily. In recent years, powdered cocaine has permeated more than just the upper class society; now, more and more people in middle income brackets use cocaine recreationally due to price decreases of the Class A drug. Some believe the increased usage can be attributed to the relatively high work hours in England. One anonymous interviewee claimed, “You can do coke tonight and go to work tomorrow and no one will know.” Cocaine is so prevalent in the social life of London that bars have even designated specific areas for patrons to get high. 

Researchers in a 2019 study on pharmaceuticals in the Thames found forty-four pharmaceutical and two lifestyle drugs in the collected samples. The discovery of lifestyle drugs, like hormonal birth control, in the Thames pushed lawmakers and government officials to require the purification of the water system in a 2012 bill. The main active chemical in contraceptive pills, ethinyl estradiol (EE2), severely alters fish health by causing an intersex condition in which male fish miraculously support eggs in their testes. Consequently, fish populations have declined in the Thames. Because the Thames is so closely tied to the groundwater system, and wastewater treatment centers can spill into drinking water, EE2 can end up in drinking water, thus causing currently unknown health effects on humans. Many Londoners rely on aquifers consisting of groundwater as their main drinking water supply. Widespread sewage pollution in the Thames and accidental leaks from the sewer tanks can drain down into groundwater, especially when heavy rainfall and higher high tides cause the river to flood. Such floods consequently contaminate London’s drinking water. 

Sewage pollution has always been an issue in the Thames. Way back in 1865, Joseph Bazalgette argued for the creation of sewers in London after the Great Stink of 1858. Previous to Bazalgette’s sewer proposal, sewage and other waste matter flowed freely down the Thames as the only means of disposal. When the summer of 1858 brought record-breaking heatwaves, the sewage began to smell awful, prompting Bazalgette to encourage a new way to deal with the increasing sewage. Sewage mismanagement can lead to serious human illnesses. For example, Bazalgette connected the malaria outbreaks in military troop encampments to the lack of waste-matter removal and treatment. Such outbreaks can happen again on a larger scale if Thames Water continues to mishandle London’s sewage. London did follow Bazalgette’s suggestion and created a new system of waste disposal, which is still in use today.

Bazalgette outlined utilization of ‘lost’ rivers to guide the sewer system; these rivers were lost as people filled in and built over them. These lost rivers would flow into a larger system that eventually led to east London balancing tanks, or tanks used to balance out the rivers’ unpredictable flow rates. The system was designed to overflow into the Thames when severe storms and heavy rainfall hit the city, which only occurred a few times a year during the Victorian era. Now, however, these weather events happen weekly, and the system has fifty annual overflows into the Thames. The sewers are currently a “combined” system; rainwater, runoff, and regular sewage all flow through it. The Thames Tideway project plans to implement a £3 billion new tunnel under the existing sewer system for the overflow sewage that the current system releases into the Thames, and then build parallel “sustainable drainage systems” for runoff and rainwater. Tideway claims this new system will be able to deal with the ever increasing sewage in a more environmentally-friendly manner.

City workers and scientists have recently begun finding large “fatbergs” in the sewer tunnels, which reinforces Bazalgette’s assumption that London sewers will have to increase in size in order to accommodate growing populations. Fatbergs consist of various sanitary items that were improperly flushed down toilets, and of grease and animal fat Londoners pour down their sink drains. Used condoms, diapers, wet wipes, and tampons combine with the grease to form large clumps in the sewers. Over time, as more items accumulate, the clump hardens into a cement-like substance, and causes major drainage problems. In September of 2017, for example, Thames Water found a massive 250-meter long fatberg in an east London sewer; it took them three weeks to remove it. For perspective, the fatberg was nearly three football fields long, and as heavy as an adult blue whale. London could follow in the footsteps of other countries and lessen the load on the sewer system by putting small waste bins next to toilets for toilet paper and other sanitary products, and place signs in bathrooms to remind foreigners not to flush anything other than human refuse. 

Considering London’s projected future population growth, its sewers will not be able to handle much more sewage, as it is already struggling with the current amounts. Thames Tideway’s plan will solve the problem in the short term, but in another century, the system will need another upgrade. 



Bazalgette JW. (1865). On the main drainage of London: and the interception of the sewage from the River Thames. W. Clowes and Sons, London. 

Groundwater. The Geological Society. Retrieved from

Kale, S. (2019, January 30). The white stuff: why Britain can’t get enough cocaine. The Guardian. Retrieved from 

Lydall, R. (2019, October 10). Londoners snort 23kg of cocaine a day… twice as much as any other European city. Evening Standard. Retrieved from

‘Monster’ fatberg found blocking east London sewer. (2017, September 12). BBC News. Retrieved from 

Thames Water fined £2.3m for Henley fish-death pollution. (2021, March 2). BBC News. Retrieved from 

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White D, Lapworth DJ, Civil W, and Williams P. (2019). Tracking changes in the occurrence and source of pharmaceuticals within the River Thames, UK; from source to sea. Environmental Pollution: 249: 257-266.

Wyatt, T. (2019, January 21). Record cocaine levels in Thames probably not making fish high, experts say. The Independent. Retrieved from 

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