Cassava from reclaimed mine lands dangerous – Study reveals

A joint study by researchers from Koforidua Technical University and the Kwame Nkrumah University of Science and Technology (KNUST) has revealed alarming levels of cyanide and lead in cassava grown on reclaimed gold mining lands in Pameng and Gyadam in Ghana’s Eastern Region.

The findings have raised serious public health concerns, especially because staple food crops like cassava are not routinely tested before they reach markets, homes, chop bars and restaurants across the country. The study highlights how dangerous chemicals used in illegal mining can remain hidden in food, long after mining activities have stopped.

Illegal small-scale mining, commonly known as galamsey, has over the years destroyed farmlands, polluted rivers and streams, and damaged forest reserves. Even after mining pits are filled and trees replanted through reclamation, toxic substances such as mercury, cyanide and heavy metals remain trapped in the soil.

“They are washing mining residue into streams and rivers, which go deep into the surrounding environment, farmlands, and into underground water. And so, by poisoning the water sources, we are poisoning the entire farming area, where we live, and spreading contaminants across. And this is backed by research,” said journalist and environmental advocate Erastus Asare Donkor.

Although the government has invested heavily in land reclamation, with estimates suggesting it could cost up to $10 billion to fully address the effects of galamsey, scientists say reclamation does not immediately remove toxins from the soil. Over time, these chemicals slowly leach into crops grown on such lands.

Cassava, one of Ghana’s most important food crops, is at the centre of the study. With more than 70 percent of farmers involved in cassava production and over 22 million metric tonnes produced annually, the crop is consumed daily in various forms such as fufu, gari and kokonte. Despite its importance, cassava’s white flesh gives no visible sign of chemical contamination.

Pameng and Gyadam, two communities with a long history of illegal mining, are also major cassava-producing areas. Although mining pits in these areas have been reclaimed and farming resumed, the research shows that dangerous chemicals remain in the soil and are absorbed by the cassava.

“The nutritional quality of cassava roots from the reclaimed and non-mine sites was comparable; however, those from reclaimed mine sites had unacceptable levels of cyanide and heavy metals, indicating possible safety issues concerning their consumption,” said the lead researcher, Dr Yaw Gyau Akyereko.

The research team used standard laboratory methods to compare cassava from reclaimed mining sites and non-mining areas. They tested for nutrients such as protein and fat, as well as toxins like lead and cyanide. The results showed that while nutrient levels were similar, toxic substances were dangerously high.

Cassava from reclaimed mining sites recorded cyanide levels ranging from 61.05 to 156.07 mg/kg, while those from non-mining areas ranged from 41.76 to 79.04 mg/kg. All these levels exceeded safe consumption limits.

“The toxic heavy metals are dense and difficult to remove or wash away. After consumption, consumers have tendency of undergoing through oxidation; radicals that can cause cancers, paralysis-linked neurological disease, and dysfunction. Infants may suffer from anaemia, constipation and fatigue; mental issues and dysfunction of the respiratory system,” Dr Gyau Akyereko explained.

Farmers in the affected communities say they have long suspected that mining activities were affecting their produce. Samuel Kwabena Owusu, a farmer in Pameng, said galamsey forced him to stop planting for months because of fear of chemical contamination.

“When the galamsey started, we stopped planting cassava for ten months, plant after ten months, because if we rush, we may suffer from the chemicals they use,” he said.

He added that even though the contamination is not visible, the impact is clear in reduced yields and poor crop quality.

“When the dirty oils they use seep into the soil, they go deep, and whatever you plant gets destroyed. We used to harvest big quantities, but when galamsey came, the harvests became small, and now you can’t harvest much like before,” he noted.

The concern goes beyond farming communities, as contaminated cassava is sold in markets and consumed widely. Many consumers say they are shocked by the findings, as they had no idea such risks existed.

A regular fufu consumer, Ofori, said, “Even though chemicals may be in the cassava crops, we will reduce how often we eat fufu, but not stop entirely. Cassava is largely consumed, so stopping completely would be difficult. What is needed is to address the root cause and deal with this properly.”

Experts say the lack of routine testing of raw food crops by regulatory bodies like the Food and Drugs Authority leaves consumers exposed. Dr Gyau Akyereko believes time is a critical factor in reducing contamination but insists farming should be restricted on reclaimed lands until safety is assured.

“There hasn’t been any further study to ascertain. But based on our findings, the longer the reclamation period, the lower the levels of cyanide and lead. Until the time we have concluded that the land is safe to use, it’s important that there is a temporary ban on cultivation on reclaimed lands,” he said.

He also suggested soil treatment methods such as adding lime, restoring microorganisms and planting remediation crops to help reduce heavy metal levels naturally.

Environmental advocate Erastus Asare Donkor has warned that Ghana is risking a major public health crisis if illegal mining and chemical pollution are not stopped.

“I have said this so many times that we are playing with fire. When it comes to contaminating our food chain, it is happening and it is real. I have seen some government ministers trying to downplay or belittle this practise. But this is a very dangerous practise we are joking with, we are toying with. If we do not end cyanide leaching by small-scale illegal miners across the country, we are in for a very dangerous precedent,” he cautioned.

The study has renewed calls for stricter enforcement against illegal mining, improved land reclamation standards and stronger food safety monitoring. As scientists, farmers and consumers all raise concerns, the message is clear: Ghana’s food chain may already be under threat, and urgent action is needed to protect public health…CONTINUE MORE READING>>>