Imagine drinking a cup of water
straight from a river in the village
over Christmas, thinking that it is
refreshing and pure.
What if, instead of just clean water, it came loaded with chemicals — specifically, sex hormones?
That is exactly what new research has found in rivers across western Kenya and the Rift Valley, which millions of people rely on for their daily needs.
These sex hormones, including powerful estrogen compounds are making their way into the water, largely because the human body does not fully absorb them.
After being excreted, they end up in wastewater and rivers, researchers said. Their study, published in Environmental Pollution journal, paints a concerning picture.
“Contamination of water resources with endocrine-disrupting steroids may not only impact aquatic ecosystems but also pose health risks to humans,” wrote the researchers, who include dons from Moi University.
They warned that exposure to some of these compounds can lead to feminisation in men, such as enlargement of male breasts.
They can also lead to early puberty in adolescents, menstrual cycle disruptions in women and increased risks of hormone-related cancers.
Some hormones have been linked to male fish developing female characteristics and masculinisation of female fish, in other parts of the world, they said.
The researchers tested water from five rivers —Rang’wena, Sare, Rangwe, Asao and Lambwe — and five waste water treatment plants in Migori, Kisumu, Kericho, Homabay and Kisii counties.
Their study, titled, “Occurrence and potential risk of steroid hormones in selected surface water and wastewater treatment plants in western Kenya”, was published last week.
The study was led by Isaac Cheruiyot and Faith Kandie, from the Moi University’s Department of Chemistry and Biochemistry.
Cheruiyot and his colleagues also found traces of steroids from family planning contraception.
“Contamination of water resources with endocrine disrupting steroids may not only impact aquatic ecosystems but also pose health risks to humans,” they said.
At least 63 per cent of married women and 70 per cent of unmarried women in Kenya use such medication, according to the Demographic and Health Survey 2022.
These drugs contain synthetic hormones such levonorgestrel and 17α-ethinylestradiol, which, when excreted, are not effectively removed by wastewater treatment plants.
Most Kenyans in the sampled areas drink untreated water from the rivers. The contamination is not unique to Kenya.
The authors said steroids occurred at similar or higher concentrations in Kenyan effluents and river samples compared to those found in European rivers and WWTPs.
However, unlike in Europe, river water is directly used as source of drinking water in Kenya.
“Over 56 per cent of the Kenyan population consumes water from rivers as they lack access to clean piped water,” the authors noted.
Cheruiyot and his colleagues identified a total of 43 steroid compounds, with 24 found in both rivers and waste water treatment plants. In rivers, estradiol, a natural female sex hormone produced by the ovaries, was the most frequently detected hormone, found in 64 per cent of samples.
Other detected hormones included estrone, estriol and androsterone. Sex hormones are are chemical substances produced by the body to regulate sexual and reproductive health in males and females.
“The hormone estradiol is excreted via human and animal urine and is released into water sources primarily through wastewater discharges,” the study explained.
“In 16 per cent of cases during the dry season, estrogenic concentrations exceeded safety thresholds, indicating likely impacts on exposed organisms,” the researchers said.
The glucocorticoid mometasone furoate had the highest median concentration among all detected hormones in rivers.
This hormone, commonly used in anti-inflammatory medications, reflects the broader issue of pharmaceutical contamination.
