Angola’s Central Agro-Food Laboratory has refused a request to do a safety analysis on samples of raw sewage taken from a Chinese-owned vegetable farm that uses human faeces as a fertiliser.

The call for an examination of the sewage samples followed public outcry over the biosafety of vegetable products from the farm, which are sold widely in horticultural markets around the capital Luanda.

Central Agro-Food Laboratory director Cleunice da Costa said the institution could not examine the samples because its mission does not include the analysis of human faeces.

He said the laboratory, which is owned by the Ministry of Agriculture and Rural Development, is mandated to analyse soil samples and test domestic and imported food products, as well as organic and inorganic fertilisers, to ensure public health safety.

Luanda Provincial Director in the ministry Mario de Ceu said the government would ensure the samples are sent for testing elsewhere in order to determine the next course of action. Such measures may include the closure of the farm if the use of raw sewage as a fertiliser compromised its horticultural products and threatened public health or environmental safety.

Reports on the use of human faeces as fertiliser at the Chinese-owned farm were circulated on social media by residents who were annoyed by air pollution, especially the putrid smell of wet faeces coming from the farm. They alerted the Luanda health department, which triggered government intervention in the matter.

PATHOGENS

According to Wikipedia, while the use of faeces as fertiliser may be an attractive and seemingly cheap option in the face of increased demand, the use of unprocessed human faeces (also known as “night soil”) is a risky practice because it contains various disease-causing pathogens.

“Nevertheless, in some developing nations, it is still widespread. Common parasitic worm infections, such as ascariasis, are linked to night soil use in agriculture, because the helminth eggs are in faeces and can be transmitted from one infected person to another,” reads part of the analysis on the dangers of using human excreta as a crop fertiliser.

Although the disease risks can be reduced by the use of proper faecal sludge management techniques like composting, the residue can only be used for fertilising flower beds and not vegetable gardens because sludge treatment processes do not include the removal of heavy metals.

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