The farm is irrigated with water from an old diesel-run pump, which draws the brown murky water from the contaminated river and sprinkles it on the neat row of pepper, tomatoes and okra.

Vegetables irrigated by this contaminated water could have traces of heavy metals and chemical residue, such as arsenic and mercury, that research by the Water Research Institute (WRI) has found in the river.

The World Health Organisation (WHO) points to the possibility of the chemicals causing a range of conditions, including cancers, heart disease, brain, kidney and liver diseases, muscle and general weakness.

Farmers along the river said it was the only source of water for cultivation. "We do not have any other source of water. For years, we have been using this water to cultivate our crops," they said.

"We know you want to expose us by showing how we use this dirty water to grow leafy vegetables, but everybody across this stretch on the central and western parts of the Birim uses the same water. We are not doing anything wrong," one of them said.

Pollution of water bodies

Ghana has various water bodies and large areas of forest reserves. The country also has several mineral deposits, especially gold, which generate large revenues for the state.

However, the growing menace of Chinese and other illegal gold miners has led to the pollution of most of the water bodies and has also impacted negatively on the country’s agricultural activities.

These unlicensed miners use unapproved methods to excavate the land indiscriminately and also destroy the forest cover which absorbs the earth’s carbon dioxide (CO2) and exposes the land to erosion.

They also use harmful substances which end up in the nearby rivers, major source of water for both domestic and agriculture purposes for the rural folks, a situation that makes them vulnerable.

 Law enforcement

Ghana’s mining laws require that mining companies treat water used for mining activities before they are discharged, but in the case of the illegal miners, water bodies are their central place of operation, a situation that makes communities living along rivers vulnerable to the risks of the dangerous chemicals. 

Most communities, where these minerals can be found, are not easily accessible by rail or road and are sometimes too dangerous and risky to access on foot.

This makes policing and checking of illegal activities a daunting task to the security and law enforcement agencies.

But according to a remote sensing technology expert, there is a solution which does not need boots on the ground.

 The use of remote sensing technologies and hyper-spectral cameras can be the smartest solution to this complex problem, as it has a positive implication on land management, food security and disaster (such as fires and floods) management.

Adopting remote sensing applications

According to Mr Francis Kudjoe, the only Ghanaian graduate of the International Space University in Israel, the only way for the government to curb illegal mining is to adopt the use of remote sensing applications, such as drones and other Unmanned Aerial Vehicles (UAVs) with appropriate sensors and hyper-spectral cameras to track down such activities.

He said the use of the technology in the mapping of the country’s land resources would offer a cheaper and more flexible option for surveillance, reconnaissance in remote areas and inhospitable terrain endowed with gold and other natural resources of high economic value.

He said the technology would also assist in advocacy, policy formulation and information to the government on the state of unlawful activities that destroy the country’s vegetation.

Mr Kodjoe indicated that the application had been used in other parts of the world to support water resource management, to detect forest fires, map vegetation cover and study structural changes of a landscape.

He added that it enabled the user to obtain a bird’s eye view of target areas on the ground.

He observed that the implementation of the space application strategies for ground monitoring would prevent indiscriminate and illegal mining and environmental degradation in Ghana.

“With remote sensors, Ghana can plan its land and natural resources, be able to tell where there is gold or oil and create buffer zones along river bodies and forest reserves. It would also help the country in allocating concession to investors or private individuals who want to mine,” he said.

The Space expert said hyper-spectral cameras aboard unmanned aerial vehicles, which had the capacity to fly at high altitudes above human vision, could track and map areas of operation of the illegal gold miners to enable security officers to arrest them.

Acquiring a space vehicle

Touching on the cost of a space vehicle with remote sensing facilities, he said the cost was equivalent to a jet fighter plane or a helicopter.

He was also quick to add that Ghanaians needed to developed interest in studying space science, adding that the technology could be used in all sectors of the country’s economy: commerce, banking, telecommunication, aviation, shipping and broadcasting.