As people increasingly turn to antibiotics, the drugs are finding their way into water resources, resulting in pollution and related health complications.
In a study conducted by the University of York in the UK, researchers found that rivers in countries such as Ghana, Nigeria and Kenya have antibiotic levels that have surpassed the safe limit.
The York study analysed levels of 14 commonly used antibiotics in rivers of 72 countries. Sixty-five per cent of them were found to have varying levels of antibiotics.
These include metronidazole, which is used to treat skin and mouth infections; clarithromycin, which is used as a treatment for respiratory tract infections like bronchitis; and Ciprofloxacin, which treats infections of the skin and urinary tract.
The researchers collected the data from 711 sites including well-known rivers such as Danube in Austria, the Thames in Britain, the Nairobi River in Kenya, the Mekong, a trans-boundary river in Southeast Asia and the Tigris in Iraq.
They established that high-risk sites are typically next to wastewater treatment plants, waste or sewage dumps as well as in areas experiencing political turmoil.
Trimethropin, which is used to treat urinary tract infections, was the most prevalent antibiotic in rivers as it was detected at 307 of the 711 sites tested.
Nairobi River, for example, is filled with vaccines owing to dumping of raw sewage into it. The river’s antibiotic levels were 100 times the safe level, the study found.
According to the AMR Industry Alliance, a private sector concern that seeks to curb antibiotic resistance, safe levels range from a low of 20 nanograms per litre (one nanogramme is a thousand-millionth of a gramme) to a high of 32,000 nanograms per litre.
Experts say that the study provides evidence that millions of people may be ingesting worrying levels of antibiotic-laden water without their knowledge.
This exacerbates the problem of resistance to common diseases, which the United Nations terms “a global crisis.”
The York University research shows the level of antibiotics present in rivers, streams and other water bodies is higher in areas near solid and wastewater treatment plants or sewage dumps. This is where municipal waste — which has high levels of human urine and faecal matter — collects.
This means that the inability to treat sewage especially in urban areas results in the presence of the antibiotics in water that is consumed by people and animals downstream.
Alistair Boxall, professor of Environmental Science at York University termed the study’s findings “eye-opening and worrying.”
According to Prof Boxall, pollution can be addressed by investing more in the development of infrastructure for waste and wastewater treatment, tightening anti-pollution regulations and cleaning up already contaminated sites.
“Solving the problem is going to be a mammoth challenge,” he said.
Reports show that most, if not all African countries are unable to effectively handle urban waste. This has led to increasing levels of pollution in the continent’s rivers and attendant health problems.
In Kenya, many of the country’s top rivers, especially those that pass across major cities and towns, have poisonous water flowing along their courses. This is more pronounced in Nairobi.
“It is sad that people living downstream of Athi River, whose tributaries pass through Nairobi, use the water for domestic and farming needs,” said Violet Matiru, an ecologist and former employee of the Kenya Wildlife Service.
She said that this has been like a “death sentence” for these people whose interests are hardly catered for by environmental agencies in Kenya.
“All of us must address pollution…because whether we live upstream or downstream of rivers, whether we are rich or poor, we all suffer the negative effects of water pollution.”
In Tanzania, reports show that the Misimbazi River in Dar es Salaam is heavily polluted with waste water from industrial, urban and agricultural sources.
A study by environmental scholar Ghanima Chanzi titled Heavy Metal Pollution Assessment along Msimbazi River, Tanzania shows that as the river flows from Mbezi Luis and Kinyerezi suburbs on its way to the Indian Ocean, it suffers from dumping of industrial and human waste leading to chromium VI levels that are 75 times the allowed limits. Chromium is used in steel production.
Although authorities in Tanzania are yet to ascertain the net effects of river pollution on human health, there are suspicions that this could be negatively affecting residents who use the River Msimbazi’s water to irrigate their vegetable gardens.
Indeed, the European Medicine Agency and the Tanzania Bureau of Standards have separately warned that the water in the river is dangerous to human health and unfit for domestic and agricultural use.
The greatest difficulty is that with about 5.3 million people, Dar es Salaam’s sewerage and waste water treatment systems can only handle 10 per cent of waste water generated every day.
However, reports show that the Dar es Salaam Water and Sewerage Authority plans to invest some $600 million to spruce up the city’s sewerage system and raise its capacity by 30 per cent by 2020.
In South Africa, the Water Research Commission warned in a 2016 report that the level of chemicals in the water consumed by millions of people was a huge threat to public health and that it has greatly endangered the wildlife dependent on it.
Studies done in the country in 2014 also showed that water in Rietvlei Dam, on which over 27 per cent of residents of Pretoria have depended for domestic water since 1933, has chemicals that not only pose cancer risks but also destroy water fowl and cause sexual changes in fish.
Prof Riana Bornman from the University of Pretoria, as was quoted in the media saying that when researchers tested male animals and fish that depend on the Rietvlei Dams water, they found that industrial and agricultural chemicals had led to the formation of oestrogenic chemicals that caused “the feminisation of male creatures.”
In a 2012 study, researchers reported that men exposed to DDT — in an area where it was sprayed to combat malaria — had impaired semen, a weak association with sperm chromatin defects (that are linked to natural reproductive malfunctions such as spontaneous abortion as well as assisted reproductive), as well as higher risks of birth defects in children born to mothers whose houses were sprayed.
Zambia on the other hand suffers the added challenge of how to deal with the negative effects of mineral production in the form of spillage into water sources.
In 2015, residents of Hippo Pool Village who depend on the Kafue River sought the intervention of a British court against a multinational copper mining firm, Vedanta Resources Plc, accusing it of poisoning their water bodies and converting Mushishima and Kafue into “rivers of acid.”
The residents produced documents in court that showed how the company, whose Zambia-based subsidiary is known as Konkola Copper Mines — had spilled sulphuric acid and other toxic chemicals into the water sources, leading to sicknesses and destruction of farmlands.
Experts say that municipal waste is not as serious a problem as the effects of large amounts of industrial pollutants that enter into water supply systems.
Chemicals such as arsenic, coal ash and mercury for example, lead to acid rain and thermal pollution. Further, researchers say that exposure to chemicals can lead to diseases such as cancer, birth defects and even death.