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Rumbidzayi Zinyuke Manicaland Bureau
The use of sewer water for irrigation purposes has become increasingly common in urban areas as people seek to grow vegetables for their own consumption and for sale at local markets.

While urban farming has been sustaining many families, the use of sewer water for irrigation might be putting more people at risk of contracting diseases.

This practice has been going on for decades in some areas, but the advent of the Covid-19 pandemic has forced health experts to relook the risks associated with it.

According to research, infected people excrete the pathogen, which finds its way into the sewer pipes that are eventually feeding the urban farmers before getting to treatment plants.

The use of untreated waste water to irrigate crops is widespread with nearly 30 million hectares worldwide being irrigated in this manner, exposing millions of farmers, vendors and consumers to health risks.

The raw, untreated waste water is preferred for its higher concentration of nutrients that cancels the need for expensive fertilisers.

Destiny high density area near Chikanga, Mutare is only one of the many places where urban farmers are vandalising sewer pipes and manholes to harvest the waste water in Zimbabwe.

And despite several attempts by local authorities to curb this, they always come back.

These farmers come to their fields daily to water their vegetables using buckets and they are selling the same vegetables at the decentralised produce markets in Chikanga, Hobhouse, Sakubva and Dangamvura.

But with no protective clothing, the farmers might have knowingly exposed themselves to various diseases and unknowingly to Covid-19. The same could be happening to consumers of their produce.

Mutare City Health services director Dr Anthony Mutara said it might be possible for Covid-19 to be transmitted through human waste although there is no evidence to support this yet.

“The assumption is that people are not ingesting human waste but if we look at the trend in urban farming, they are using sewer water that has not reached the treatment plant. Some unverified studies have shown that human excreta is about 10 times more infectious than any other body fluid (saliva and sweat) others say it is less. So when people eat the vegetables grown using this raw sewage or handle the water during farming, there might be high risk. We haven’t been able to quantify the risk associated with this but there is need for more research,” he said.

Research institutions across the world are carrying out waste water surveillance to trace coronavirus and evidence shows that local authorities might be able to detect a coronavirus outbreak early through the monitoring of sewer water.

Researchers in the UK have also warned that sewerage systems could pose transmission risk after the virus was found in human excreta 33 days after the patient had tested negative for the respiratory symptoms.

Although there have not been evidence that the virus detected in the waste can infect people, other studies show that there is increased risk in parts of the world where open defecation is still rampant.

What remains is that fruits and vegetables that are irrigated with waste water and not properly disinfected could be an indirect route of infection.

Unfortunately, for residents consuming vegetables coming from Destiny and many other areas across the country, there is not enough evidence yet to show if they are at risk of contracting the deadly disease by simply eating fresh fruit and vegetables.

They can only hope something is done soon to curb the practice.

• This story is part of our Covid-19 Newsletter currently being accessed under the Coronavirus Watch section on The Herald Website