A woman buys vegetables at a market in Kampala yesterday. Researchers at Makerere University say they have detected worrying levels of cancer-causing agents vegetables grown near dumpsites. PHOTO/FRANK BAGUMA


Kampala vegetables, milk linked to cancer

What you need to know:

  • Researchers say the items  have concentrations of metals such as iron, cadmium, chromium, lead and nickel higher compared to WHO limits.

Researchers at Makerere University have said they have detected worrying levels of cancer-causing agents in milk, vegetables and fruits from Kampala farmers.

The six-member team said it assessed heavy metal contamination in water, crops and sampled cow milk near selected dumpsites.

The study was done between March and December 2021, with samples picked from Mukono, Wakiso and Kampala. 

The researchers say 42 crop, 14 milk and 37 water samples from the dumpsites were analysed at Makerere University’s Department of Food Technology, and the Department of Geology and Petroleum Studies laboratories.

“The mean concentrations of [metals such as] iron, cadmium, chromium, lead and nickel in all sites were higher compared to World Health Organisation (WHO) limits for heavy metals in vegetables and fruits,” the report reads in part.

The researchers say these findings were hardly surprising because dumpsites in the Kampala Metropolitan area are poorly designed, overloaded and receive wastes of different characteristics, including the hazardous type.

Some of the toxic agents seep out from electronic wastes, steel and iron metals and other wastes from construction sites, the researchers further note.

The mix-up of the agents is consumed directly or indirectly through drinking water and eating contaminated plants. 
Domestic waste in grazing areas also makes contamination in milk rife.

Vegetables that are grown in the area also absorb toxic metals that are consequently ingested by humans.

Spike in cancer cases
The revelation comes on the back of the Ministry of Health’s proclamation that death rates from non-communicable diseases such as cancer and heart diseases in the country increased from 33 percent in 2016 to the current 41 percent.

The lead researcher, Mr Abdullah Ali Halage, an assistant lecturer in the Department of Disease Control and Environmental Health at Makerere University School of Public Health, says these metals have various effects on consumers from cancer to heart diseases.

“We need some of these trace metals such as zinc, iron and manganese for the normal functioning of our body. They are micro-nutrients. But beyond some level, they become dangerous and poisonous to our body,” he says.

He adds: “Cadmium and lead are not needed by the body even in very little concentration. They almost affect all our body parts such as the nervous system, the heart and blood vessels, and they cause cancer.”

The study funded by the government focused on determining the presence of those metals. The researchers say they intend to study the exact impact of the substances on humans living near dumpsites and feeding on crops grown in the neighbourhood.

The other researchers included Dr Robert Mugabi, Dr Joel Kinobe, Assistant Prof Ahamada Zziwa and Mr James Muleme from the Makerere University School of Public Health, School of Food Science and Bio-Engineering, and the Department of Civil and Environmental Engineering.

According to the report, the most abundant heavy metals from the leachate (water seepage from dumpsites), and crops in all selected dumpsites were in the order of iron, manganese and zinc.

“However, in milk samples, the concentrations were highest in the order of zinc, nickel and iron. The mean concentration of manganese, lead and iron was above the acceptable limits of the WHO, and the national standards for leachate in all sites,” the report adds.

Way forward

In their recommendation, the researchers note that “heavy metals must be monitored regularly in leachate, milk and crops by the local authorities and the environment and food standards agencies since they are likely to lead to detrimental effects to human beings if consumed for a long time.”

They also recommended that the Ministry of Health, the district health teams and non-government organisations working on public health issues should sensitise the population about the possible dangers of consuming milk and crops grown around the dumpsites.

Dr John Ssempebwa, a senior lecturer in the Department of Disease Control and Environmental Health at Makerere University, says there is an urgent need to control all the activities within the areas surrounding the waste disposal sites.

“Animals are being grazed there and farmers are growing their crops in these areas. We need to make sure these activities are restricted and prevented from taking place in these areas,” he says.

Mr Sammy Ejoga, the health inspection and education officer at Kampala Capital City Authority, who represented the agency at the launch of the report at Makerere University in Kampala on Thursday, said they will take action to prevent the damaging effects of the wastes on people and the environment.

“These results will inform us about our management of wastes, especially in the landfills. As you are aware, Kitezi landfill [one of the locations where the study was conducted] is at full capacity and it is supposed to be shut down soon and we are going to relocate to a new landfill in Mukono,” he said.

For now, Mr Ejoga said: “…we are going to put into place some of the measures [to minimise the seepage of the heavy metals]. We have a treatment plant that treats leachates, although it is not focusing on heavy metals. It is a key issue that we should take up based on the recommendation of the study.”

The research---Crops analysed
●   Amaranthus (dodo)
●   Bitter berries (Katunkuma)
●   Yams
●   Pumpkins
●   Pawpaws
●   Pastures for animals such as elephant grass

Study areas
●    Mukono dumping site
●   Entebbe dumping site (Wakiso)
●   Kitezi dumping site in Kampala


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