How Safe is Your Sukuma Wiki?

You might want to find out where the vegetables come from before you eat your next meal.
Most likely, you purchased them from your favorite “Mama Mboga” or your neighborhood store, but did you know that by doing so, you can be exposing yourself to heavy metals that are bad for your health?
Following extensive testing of samples from numerous food markets throughout the city as well as two major supermarkets, the Star’s investigation revealed that you are better off purchasing sukuma wiki (kales) from your local market than at a supermarket.
The one kilogram of kale samples were obtained from the markets in Gikomba, Marikiti, Korogocho in Kariobangi, Kangemi, and Githurai, as well as from the Naivas and Nakumatt supermarkets in Westlands and Lavington.

Both the Kenya Plant Health Inspectorate Service (Kephis) and a private laboratory, Analab Limited, subjected them to laboratory examinations.
For verification purposes and to identify a trend in the concentration of metals in sukuma wiki in Nairobi marketplaces, testing were conducted in two independent labs.

The tests were done to find out if (and how much) lead, mercury, iron, copper, and cadmium were present in the kale that was purchased at the main markets and supermarkets in Nairobi.

According to laboratory tests carried out at Kephis, the kale purchased from the two nearby supermarkets had 0.13 mg and 0.15 mg of mercury, respectively.

This exceeds the 0.1 mg per kg limits advised by the World Health Organization. The samples from the markets had levels that were within WHO-acceptable standards, ranging from 0.007 mg per kilo to a high of 0.1 mg per kilo.
But there was also more mercury in the kales from the Kariobangi market, 0.11 mg per kilo.
Samples from the Kangemi, Gikomba, Githurai, and Marikiti markets, at 0.06, 0.07, 0.05, and 0.05mg per kilo, respectively, fell below the allowed limits.

This exceeds the 0.1 mg per kg limits advised by the World Health Organization. The samples from the markets had levels that were within WHO-acceptable standards, ranging from 0.007 mg per kilo to a high of 0.1 mg per kilo.
But there was also more mercury in the kales from the Kariobangi market, 0.11 mg per kilo.
Samples from the Kangemi, Gikomba, Githurai, and Marikiti markets, at 0.06, 0.07, 0.05, and 0.05mg per kilo, respectively, fell below the allowed limits.

Analab tests revealed that the samples’ mercury concentrations were within the prescribed WHO limits at 0.01 mg per kilo. However, the majority of Nairobi’s marketplaces’ kales contained appreciable amounts of lead.
Kales from Westlands’ Kangemi market had a level of 0.20 mg per kilo, while those from Kariobangi’s Korogocho market had a level of 0.17 mg per kilo. The highest lead concentrations were found in kales from the Gikomba market, which had 0.23mg per kilo, and Githurai market (0.08mg per kilo).
Wakulima/Marikiti marketplaces in the Central Business District, on the other hand, displayed substantially lower lead concentrations than the others, at 0.01 mg per kilo.

Despite the fact that animals and plants typically have relatively low levels of total mercury, repeated exposure from eating tainted food can be harmful since methylmercury is toxic to the nervous system, kidney, liver, and reproductive organs.
According to a fact sheet published on the WHO website in March 2017, mercury poses a serious risk to public health because even low levels of exposure can harm human development, especially in developing infants.
Anyone exposed to considerable amounts of mercury over time may experience toxic effects on their nervous, digestive, immune, lungs, kidneys, skin, and eyes, significantly impairing these functioning and jeopardizing their health.

The Minamata Convention on Mercury, whose 74 Parties have agreed to reduce the hazards to human health and the environment from the unintentional release of mercury and mercury compounds, entered into force in August 2017.
On October 10, 2013, Kenya ratified the convention, making it legally obligated to prohibit new mercury mines, restrict the use of mercury in small-scale and artisanal gold mining, manufacturing processes, and the creation of common goods including cosmetics, lightbulbs, batteries, and dental fillings.

Eight Kenya National Bureau of Statistics employees and two merchants are currently being tried for attempted murder for enabling the importation of subpar fertilizer containing mercury. The case is still pending. This demonstrates Kenya’s dedication to preventing the harmful usage of mercury.

The 10, who included former Kebs CEO Charles Ongwae, were accused of bringing in 5.8 million kg bags of inferior fertilizer that was purportedly contaminated with mercury. However, as of this writing, a January 2019 order to retest the fertilizer has not been carried out.
The Star also conducted tests on the kale from the two supermarkets and the open-air markets for the presence of lead and cadmium, two heavy metals that are known to have detrimental effects on human health.

According to a joint assessment on food standards from the UN Food and Agriculture Organization and the WHO, children between the ages of 1-4 years were exposed to an average of 0.03 to 9 g of lead per kilo of body weight per day through their diet. It varied for adults from 0.02 and 3g per kg of body weight every day.
Lead exposure can come from a variety of places, although it typically results from industrial use. During mining, smelting, processing, usage, recycling, or disposal, lead and its compounds may enter the environment.
Batteries, cables, pigments, plumbing, solder, steel goods, food packaging, glassware, ceramic items, and insecticides are some of the principal uses for lead.

According to the WHO, lead exposure for the general adult population who do not smoke occurs mostly through food and drink. According to WHO’s International Programme on Chemical Safety, “Food, air, water, and dust or soil are the main potential sources of exposure for newborns and young children.”

It is regrettable, according to Agriculture CAS Andrew Tuimur, that legislation governing food safety standards in Kenya are not upheld.
Tuimur forbade Kenyans from planting kale alongside the roadways in order to prevent the release of gases that could contaminate the air with lead.
“Traders must make sure that kales are transported in closed trucks. Vegetables being sold on the side of the road should not be purchased. Markets near roadways should be enclosed or pushed away from them, the expert advised.
Dr. Richard Oduor, a senior lecturer at Kenyatta University, spoke on the subject and noted that even persons who appear healthy might have high blood levels of lead.

The majority of the time, signs and symptoms do not manifest until harmful amounts have accumulated. “The poisoning can result in serious physical and mental impairment,” stated Dr. Oduor from the department of biochemistry and biotechnology.
A very uncommon element, cadmium is mostly utilized in industrial paints and rechargeable batteries. Wastes containing cadmium, such as food, soil, and grass, can release the metal into the air, land, and water if they are not properly disposed of.
The heavy metal would be absorbed by plants growing in high cadmium soil, and if these plants subsequently reach the human food chain through agricultural crops, they could have a negative effect on the health of anyone who consumes them.

Human carcinogen status for cadmium. If it builds up in the kidneys, it might cause renal impairment. The WHO suggests a cadmium upper limit of 0.2 mg per kilo.
According to the test results, there were no cadmium levels in the samples.

How do these dangerous substances get into food? Head of the Plant Protection Service at the Ministry of Agriculture, Dr. David Mwangi, said they primarily come from soil and water.
This is more likely to occur if the food is grown in areas where factory waste has contaminated the land or irrigation water, the expert said.
Inorganic fertilizers, particularly those containing phosphates, have been discovered to contain trace quantities of heavy metal contaminants. Ongoing exposure to these fertilizers may cause food crops to absorb these toxins, which could have disastrous effects on human health.

The contamination may have come from the soil, the manure used, or during transport of the kale from the farm to the market, according to a lab technician from Kephis who was not authorized to speak to the press.
The lab technician advised regular testing to guarantee the sukuma wiki’s security at all times.
Kale and other vegetables are in low supply because of the widespread, extended drought. As a result, more vegetables are now being grown with irrigation, which is how many shops obtain their food.

In Kenya, irrigation is generally unregulated. It might be a source of heavy metal contamination, particularly when sewage and wastewater are involved.

Githurai market greengrocer Anne Waihiga stated that Murang’a is the primary supplier for her and other market vendors. The Wakulima market receives supplies from Nyeri, Kiambu, and Nyahururu in Central Kenya, according to dealer Joseph Ngunjiri.
There are numerous vegetable fields in Kiambu, according to Dr. Eliud Kireger, director general of the Kenya Agricultural and Livestock Research Organization. They are located in areas bordering Kiambu that extend all the way to Thika along rivers and streams. Urban farmers in the city, like those in Utawala, also provide the markets with vegetables.
However, some of these farmers occasionally purposefully damage the sewer lines. They utilize sewage water as fertilizer, but it contains pathogenic microorganisms, according to Dr. Kireger.

Because chemicals from industrial parks are mixed with sewage water, it also contains heavy metals. Chemicals containing paint and lead from car washes are flushed into the drainage system. We ultimately eat the vegetables once they have absorbed all of these.
He asserted that it is unlawful for people to irrigate their lawns using sewer water. “We need to create a traceability system where one can determine where the product originates from if they buy kale or vegetables from a supermarket,” he stated.
“The government should develop a mechanism so Mama Mboga can track the source of her vegetables and make sure the farm doesn’t use a lot of chemicals,” the author continued.

Dr. Kireger also emphasized the problems associated with farmers utilizing agrochemicals referred to as acaricides (pesticides used to kill mites, ticks and pests).
According to him, these compounds are dangerous to consume because they are quickly absorbed by veggies.
The main issue in Nairobi and the surrounding area is that wastewater, which includes unclean water from car washes and industrial effluent, ends up in the streams that feed into the rivers used for agriculture. The plants, which ultimately wind up on our tables, absorb all of this waste, according to Dr. Kireger.
According to testing by this publication, the leafy kale eaten in Nairobi may contain dangerous metals that could potentially counteract any health benefits.

The samples were purchased from three of the largest food markets in the city, which also supply a number of supermarkets, hotels, and restaurants as well as hundreds of Mama Mbogas and greengrocers.
These markets are well-liked for being close to important transportation hubs and being reasonably priced. As a result, they are now Nairobi residents’ and nearby towns’ favorite source of veggies.
When the markets opened for business in the morning, samples from those markets were purchased. The samples were transported to the testing facilities in sterile, plastic woven bags. After ten working days, we obtained the test results.


After tomatoes and onions, sukuma wiki is the third most popular vegetable, according to a 2015 study of consumers and retailers. According to reports, tomatoes, onions, carrots, cabbage, spinach, and potatoes were also very popular veggies.
According to 82% of study respondents, tomatoes are the vegetable that high-end and middle-class customers in Kenya’s three largest cities—Nairobi, Nakuru, and Mombasa—consume the most. Following spinach and suku wiki at 42% is onions in second place, according to the research.
According to the survey, supermarkets are the preferred outlet for high-end and middle-income consumers to buy both food (including vegetables) and non-food items.

According to the study, supermarkets are preferred by Kenyans for their “quality items” (84%) and convenience (76%), while petty traders and street sellers are preferred by 65% of the studied households due to their lower costs.
Only 45% of respondents travel to supermarkets to buy veggies, the research stated, despite the fact that over 90% of respondents do so for both food and non-food goods (95% for food and 96% for non-food).
Other sources of veggies for purchase include kiosks (38%) open markets (36%), and dukas (30 per cent). In addition, respondents purchase veggies from petty traders (13%) and street sellers (22%).

What do you think?

Written by Esther Oyugi

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