Topping It Off

Insecticides are essential to preventing malaria, dengue, and sleeping sickness. With funding from the President’s Malaria Initiative (PMI), the Africa Indoor Residual Spraying (AIRS) Program works in 12 countries to combat malaria through spraying the interior of houses with insecticide. To ensure insecticides are disposed of safely without harm to humans, animals, and the environment, AIRS, in compliance with PMI’s Best Management Practices for IRS, builds soak pits in the ground where wastewater containing insecticide is safely discarded. These soak pits contain a layer of charcoal and other materials that filters, adsorbs (a process in which liquid or gas is not absorbed but forms on the surface) and then degrades the insecticide so that only clean water seeps into the ground.

Although the soak pits were fenced off to prevent people and animals from accessing the area, the pits remained open to the air. AIRS found that people would break through the fences to collect the contaminated charcoal from the pit and use it for cooking. Fences also failed to keep animals, such as birds and bees, from accessing the contaminated wastewater.

“Soak pits have not traditionally been covered during the spray season or in between seasons. We realized we could decrease the likelihood of human or animal contact with contaminated water or materials by installing soak pit covers,” said Peter Chandonait, AIRS Environmental Compliance and Safety Manager.

The locked metal covers also inhibit the growth of weeds and prevent debris from getting into the pit. Before soak pit covers were introduced, workers would go to every site and remove weeds, ensuring the soak pit was ready to be used again for the next spray campaign. This process can be costly and time consuming since some countries have more than 60 soak pits that are scattered across several regions. In addition, removing the weeds can disturb the careful layering of materials and the distribution of water flow that is critical to proper functioning of the soak pit.

In Benin, AIRS piloted the use of padlocked metal covers on soak pits to reduce the environmental and health risks of the insecticide and to protect project assets.   Photo Credit: Peter Chandonait

In Benin, AIRS piloted the use of padlocked metal covers on soak pits to reduce the environmental and health risks of the insecticide and to protect project assets. Photo Credit: Peter Chandonait

Now a covered soak pit needs to be opened only once for a cursory inspection before the start of each IRS campaign, or when it is time to replace materials, saving time and money.

Introduced first in Benin in 2013, and now used in Mali and Zimbabwe, soak pit covers are becoming a standard practice for the AIRS program.

With the pits covered, the risk of human exposure is minimal, and PMI has further improved the environmental safety and compliance of IRS.