Combating the effects of soil pollution

Soil pollution is a serious challenge worldwide, resulting in environmental damage and potential health hazards to people and animals. This report examines affordable ways in which farmers can limit its effects on their crops and reduce further soil degradation.

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Human activities over thousands of years have left a legacy of polluted soils across the world. These activities include, amongst others, improper disposal of hazardous and urban waste, industrial processes, mining, military actions and armed conflicts, and unsustainable agricultural practices.

In sub-Saharan Africa, agriculture, mining, transport and energy generation are sources of soil pollution, with pesticide use by farmers considered the most significant contributor of soil contaminants. The application of fertiliser to enhance crop production has also been shown to be a source of soil pollution in the region.

Manure as a by-product of livestock production can result in soil pollution when the manure is disposed of in landfill areas or stockpiled on other bare soil surfaces. A study conducted at the Animal and Livestock Science experimental farm of the Federal University of Agriculture in Abeokuta, Nigeria, evaluated the levels of trace element accumulation in soil resulting from manure stockpiles of different types of animals.

The results indicated that soil pollution was most significant where poultry manure was disposed, followed by that of pigs and cattle.

CONSTRAINTS TO A FULL UNDERSTANDING

In parallel with sub-Saharan Africa’s rapid population growth, the estimated number of people living on less than US$1,90/day (about R30/ day) almost doubled between 1990 and 2015. With such poverty, people tend to produce their own food through subsistence or small-scale farming or forage wild vegetables, herbs and fruit.

In South Africa, vegetable gardens at schools took off as an initiative to relieve food insecurity and nutrient deficiencies amongst children. Unfortunately, analysis of soil samples in gardens close to gold-mine tailings indicated high concentrations of arsenic, lead and mercury.