Sukuma Wiki, a popular vegetable in many households in Nairobi, could be a ticking time bomb, as investigations reveal shocking details.
According to local media reports, Nairobi residents have in one way or another been exposed to heavy metals which could have adverse effects to their health.
Vegetables obtained from Supermarkets are on the spot after lab tests revealed high level of mercury, higher than the recommended levels by World Health Organisation (WHO).
The analysis, reportedly conducted in a government and private laboratories for verification purposes, sought to compare the presence and levels of heavy metals – lead, mercury, iron, copper and cadmium – in vegetables from supermarkets and those from local market centres.
The Star used 1 kilogram samples from Naivas supermarket in Westlands, Nakumatt supermarket in Lavington and local samples from Gikomba, Marikiti, Korogocho, Kangemi and Githurai markets.
They were subjected to tests in the Kenya Plant Health Inspectorate Service (Kephis) and at a private laboratory, Analab Limited.
A report from Kephis revealed that the samples from the two supermarkets contained 0.13mg per kilo and 0.15mg per kilo of mercury respectively, which is higher than the recommended 0.1mg per kilo according to WHO.
Kales obtained from Korogocho market in Kariobangi recorded high mercury level at 0.11mg per kilo.
Samples from other local markets, Kangemi, Gikomba, Githurai and Marikiti were within the WHO limit at 0.06, 0.07, 0.05 and 0.05mg per kilo respectively.
Results from Analab indicated that the samples had mercury levels of 0.01mg per kilo, which is within the stipulated WHO limits.
However, the levels of lead in the vegetables was significantly high from most markets in Nairobi.
Kales from Kangemi market in Westlands had a level of 0.20mg per kilo of kales, while Korogocho market in Kariobangi had 0.17mg per kilo. Githurai market had 0.08mg per kilo, and kales from Gikomba market had the highest levels of lead at 0.23mg per kilo.
Experts note, While total mercury levels in animals and plants are usually very low, repeated exposure through consumption of contaminated foods can be dangerous, as methylmercury is toxic to the nervous system, kidney, liver and reproductive organs.
From the tests, kales sold in Nairobi contain harmful heavy metals and continuous consumption of the vegetable may have adverse health effects to residents.
Heavy metals can end up on food through soil and water, Agriculture ministry’s Plant Protection Service head Dr David Mwangi says.
“This is likely to happen if the food is grown in places where the soil or irrigation water is contaminated with discharge from factories,” he said.
On the other hand, inorganic fertilizers, especially those with phosphates have been said to harbor small amounts of heavy metals.
According to a WHO report, mercury is a major threat to public health because even exposure to smaller amounts poses a threat to human development, especially of children in early stages of life.
The metal may have toxic effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes.
It’s considered by WHO as one of the top ten chemicals or groups of chemicals of major public health concern.
Agriculture CAS Andrew Tuimur warns farmers from growing kales on roadside, to avoid lead contamination from gaseous emissions.