Pharma in our taps
Where there are people, medicines end up in wastewater. Regulations restricting drugs in wastewater (or drinking water) is limited. Researchers at the University of Johannesburg (UJ) in South Africa recently developed a method to detect HIV drugs in wastewater and in rivers.
The method is simple and cost-effective and can also be used when testing potable water from water treatment plants.
According to Prof Philiswa Nomngongo, the DSI/NRF SARChI Chair: Nanotechnology for Water, UJ, many people in the rural areas of Africa still use streams and river water for drinking, bathing, washing dishes and to do their laundry. Nomngongo grew up in Flagstaff, a village in the Eastern Cape of South Africa.
“Kids who play in the water often get skin rashes,” she says. “People with water tanks bath in the rainwater or use the water to do their dishes and laundry. They would then release the wastewater into the closest river. Downstream, someone else drinks water from the same river,” she adds.
In the dry season, most rivers in South Africa are shallow and only a few meters wide, until flash floods arrive in summer. During the winter months livestock walks through the water and drinks from it, which further contaminates the quality. Even if the water looks clean after the rain, it is still contaminated.
Upstream from the city
People who live in large towns and cities may think that upstream contamination doesn’t affect them. After all, water treatment plants protect them, removing heavy metals, bacteria, viruses and more from their tap water.
But the tap water in large towns and cities often originate from rivers upstream. Medicines and pharmaceuticals slip through almost all water treatment plants. These medicines end up in rivers supplying drinking water to cities and towns downstream.
Pharma in our own taps
“Clear water does not always mean clean water. As researchers we know the challenges with pollutants. Water treatment plants cannot remove pharmaceuticals. And we release pharmaceuticals into wastewater daily,” says Nomngongo.
“In the big cities, people often get rid of their medication once they feel better. The easiest way to do it is to flush it down the toilet without thinking that it might come back to us through our own tap.”
Treatment plants only do so much
“The technologies at wastewater plants remove some pollutants, but not all of it,” says Dr Mpingana Akawa. She lives near the Orange River in Namibia. Akawa conducted experimental work for research as part of her PhD studies at the University of Johannesburg.
“Pharmaceuticals are regarded as emerging organic pollutants. We need to remember that most pharmaceuticals are not regulated.
“Hence there are no limits on how much should be in the effluent of a wastewater treatment plant before it is discharged into the environment.
“Because they are not regulated, these factors are not monitored before treated wastewater is released, which is problematic,” says Akawa.
Stuck between need and pollution
“Pharmaceuticals in wastewater are released into rivers every day, and it is difficult to monitor and regulate,” says Nomngongo.
Most water treatment plants are not designed to remove pharmaceuticals, which are present in the water at extremely low concentrations.
We also need to find a balance between medical treatment and collective water management.
“Mothers living with HIV have to use Nevirapine to prevent transmitting the virus to their babies. If you started regulating antiretroviral’s (ARVs), how would you regulate Nevirapine in wastewater? We need to choose between a medical need and pollution,” Nomngongo adds.
The wastewater from our homes is treated at a wastewater treatment plant in multiple stages. The treated water is then released into the closest river.
Most of these plants are therefore located close to a river or stream. If the water is not treated effectively, the river becomes polluted.
“ARVs are present in cities and in rural areas, and it’s not only HIV medication being used but also other pharmaceuticals. Only some of the medication is absorbed by the human body. The rest is excreted through urine or faeces. All this will eventually end up in surface water, such as rivers, which we drink,” says Nomngongo.
Monitoring rivers and wastewater
To complete their research, Nomngongo and Akawa’s needs to regularly monitor rivers and the effluent of wastewater treatment plants. Their methods detect two widely used antiretroviral drugs, nevirapine (NVT) and zidovudine (AZT).
The method they developed is simple, quick, and cost-effective. It requires equipment one would find in most chemistry laboratories.
Their study is published in Environmental Nanotechnology, Monitoring and Management.
“The sample preparation method was described in previous studies by other researchers. Previous studies have also monitored antiretroviral drugs in water using other methods,” says Akawa.
In this study, water samples are pre-concentrated before analysis. The composite water samples were taken from the river, upstream and downstream from a wastewater treatment plant.
“The ARVs are present at low concentrations. This means you must increase the sample concentrations to analyse with the instrument.
If you just take water from the river, and you go to the HPLC (High-performance Liquid Chromatograph), you won’t be able to detect anything. The instrument will not be able to pick up the ARVs at that very low concentration,” says Akawa.
Results in an hour
The method includes making an environmentally friendly adsorbent, which takes about two days. One of the ingredients is activated carbon made at UJ from waste tyres. The ingredients and the manufactured adsorbent can be stored at room temperature.
“Once the method is calibrated, it takes about an hour to analyse three composite water samples from a glass bottle in triplicate, says Akawa.
“The data from this study can be used as a reference when governments and legislation bodies set up guidelines for the maximum allowable levels for the ARVs nevirapine and zidovudine,” concludes Akawa.
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