Abuja and Zaria — The quantity of chemicals in preserved beans sold across the country is unsafe for consumers, as its long term effects could lead to cancer and kidney-related diseases among others, Daily Trust investigation reveals.
Checks also show that some of the pesticides have been banned in other countries but are freely used in Nigeria despite the fact that they portend grave danger to consumers.
Many farmers and grain merchants in Nigeria employ various insects control measures, including the use of chemicals, Daily Trust reports.
It was gathered that grain merchants resorted to pesticide control measures in order to mitigate losses as beans (cowpea) are highly susceptible to pest infestation, leading to huge post-harvest losses, lower food quality, and poor food safety.
Laboratory analysis carried out by Daily Trust shows that consumers of grains preserved with pesticides, including beans are at risk due to their harmful effects.
Further checks show that aside from acute effects, which include abdominal pain, dizziness, headache, nausea and vomiting, long term effects of consuming grains preserved with pesticides could lead to cancer and kidney diseases.
Samples of beans were randomly obtained from markets in six states across the geopolitical zones, including Abuja, and tested in a laboratory at the University of Agriculture Makurdi, Benue State.
The laboratory analysis revealed that the amount of pesticide residue on preserved beans sold in the markets is high and therefore harmful to humans.
An alarm on the availability of beans preserved with poisonous substances and sold to unsuspecting buyers in Nigerian markets was earlier raised in September last year by the Consumer Protection Council (CPC), Daily Trust reports.
It followed the information that had gone viral on social media about some retailers reported to be using a particular insecticide, sniper, to preserve beans.
The CPC's Director-General, Babatunde Irukera, was quoted as saying: "CPC has confirmed credible information that retailers, mostly in the open markets, are using pesticides to preserve beans. They use 2.2 Dichlorovinyl Dimethyl Phosphate (DDVP) compound otherwise marketed and known as sniper, to preserve beans."
The CPC had advised consumers to extensively parboil their beans before consuming them and to make sufficient inquiries before buying beans.
But the advice seems unheeded as Daily Trust checks revealed that farmers and marketers still use pesticides to protect beans from attacks, particularly from weevils, a sub-family of beetles that typically infest various kinds of beans or seeds, living most of their juvenile lives inside a single seed.
It was gathered that by their composition some of the chemicals used in cowpea preservation are potentially injurious when human beings are unduly exposed to them by inhalation, absorption, direct skin contact, or ingestion.
Experts lamented that sometimes the right amount of pesticide is not used. They also noted that some traders take their beans to the market even before the expiry date of the chemical used in preserving it. Actions they maintained could result in serious health hazards such as abdominal pain, dizziness, headache, nausea, and vomiting. According to them, long term health risks associated with the consumption of pesticides through stored food or other means include diseases of the kidney, prostate, breast, pancreas, liver, lungs, and skin cancer.
Among the harmful chemicals used in preserving the beans samples analysed by Daily Trust are; Permethrin, Malathion, a-Endosulfan, b-Endosulfan, Aldrin, Dieldrin, Lindane, and Heptachlor.
The laboratory analysis based on Gas Chromatography (GC) shows that the highest concentration of recovered chemical residue on preserved beans (amounting to 0.047mg/kg) was found in Permethrin followed by a-Endosulfan and b-Endosulfan with a recovered chemical residue of 0.44 mg/kg. Malathion had a recovered chemical residue of 0.01mg/kg.
Pesticides with Maximum Residue Limits (MRL) were found in Aldrin and Dieldrin (0.014mg/kg) each Lindane (0.009mg/kg and Heptachlor (0.004mg/kg).
Harmful pesticides analysed
Checks by Daily Trust show that one of the harmful pesticides used for beans preservation in Nigeria, Permethrin, is listed as a "restricted use" substance by the US Environmental Protection Agency (EPA) due to its high toxicity to aquatic organisms.
It is used both as a medication and insecticide. As a medication, it is used to treat scabies and lice while as an insecticide, it can be sprayed on clothing or mosquito nets to kill the insects that touch them.
Another pesticide, Malathion, an insecticide in the chemical family known as organophosphates kills insects by preventing their nervous system from working properly. When healthy nerves send signals to each other, a special chemical messenger travels from one nerve to another to continue the message.
The nerve signal stops when an enzyme is released into the space between the nerves. Malathion binds to the enzyme and prevents the nerve signal from stopping. This causes the nerves to signal each other without stopping. The constant nerve signals make it so the insects cannot move or breathe normally and they die.
Checks show that humans, pets, and other animals can be affected the same way as insects if they are exposed to enough Malathion as the same amount will be taken into the body whether one breathes or swallows it. Malathion is also said to be readily taken into the body through the skin, though the amount absorbed depends on where the exposure occurs on the body. Malathion can become more toxic if it has been sitting for a long time, especially in a hot place.
Humans could also be exposed to residues of Malathion, if they consume food that had been treated with this pesticide, Daily Trust checks show.
Another analysed pesticide, Endosulfan is a chlorinated hydrocarbon insecticide of the cyclodiene subgroup, which acts as a contact poison in a wide variety of insects and mites. It is used primarily on food crops like tea, fruits, vegetables, and grains.
Endosulfan is said to be a highly toxic substance and carries the signal word 'DANGER' on the label while its toxicity is said to be partly dependent on the manner with which the pesticide is administered.
While several chronic effects are said to have been noted for animals exposed to endosulfan, checks also show that the pesticide is most likely to affect kidneys, liver, blood chemistry, and the parathyroid gland.
Experts speak on implications
An Associate Professor in the Faculty of Agriculture at the Ahmadu Bello University (ABU), Zaria, Dr. Nafiu Abdu, who carried out an independent analysis of the sampled test result, said pesticides applied in the sampled beans were more than the acceptable limit for human consumption.
Dr. Abdul explained that pesticides generally have direct and indirect effects on human health.
"These effects may be acute effects that occur immediately, which include skin rashes, blisters, blindness, diarrhea, dizziness, nausea and sometimes death or chronic adverse effects that occur years after exposure. These include cancer, reproductive disorders, including sterility, still birth, abortion and infertility as well as distortion of the central nervous system et cetera," he said.
He, however, said pesticides application could be above the acceptable limit for human consumption, but that may not necessarily translate to being harmful.
"What determines the harmful effects of crops mixed with pesticides for storage is Health Risk Assessment. Therefore, health risk assessment has to be conducted before we can categorically say that the crops are harmful.
"The health risk assessment demands a long procedure that involves a lot of calculations. Parameters such as hazard quotient, average daily intake et cetera must be determined before concluding that such crops are risky for humans' health," he said.
On his part, a Consultant at the Ahmadu Bello University Teaching Hospital (ABUTH), Dr. Abdulazeez Umar, said the major issue is the failure of farmers and traders to respect the guidelines of using such pesticides.
"Every pesticide has a duration that must expire before humans can safely consume crops preserved with it. Failure to respect this largely brings about the health hazard. For example, crops preserved with some pesticides must take one or two or more years before they can be safely consumed. However, because some people are desperate to make money, they bring such crops to market sometimes in less than three months.
"This brings about instant death after consumption on many occasions. Again, this is why you hear stories that many people have died after consuming beans at a party, for example. Similarly, chronic exposure can result in Neurodegenerative disorders, kidney failure, autoimmune diseases et cetera," he said.
Why I avoid inorganic chemicals in preserving beans- Farmer
A Makurdi based large scale cowpea (beans) farmer, Vitalis Tarnongo said he uses organic resources in preserving his beans due to the harmful effects of using inorganic items (chemicals).
"I am very much aware of the harmful effect of preserving beans with chemicals such as sniper and rat poison. These can cause several health challenges to consumers such as cancer, heart failure, low sperm count and infertility.
"This is why I personally avoid those harmful chemicals and go for organic resources in preserving my beans. I am also aware that some of these chemicals are banned elsewhere but are freely used in Nigeria," Tarnongo said, adding that he also partners with the Federal University of Agriculture, Makurdi, on the use of organic chemicals in beans preservation.
Chemicals pose grave danger - Consumer Protection Council
The Federal Consumer and Competition Protection Commission (FCCPC) confirmed that beans preserved with sniper and other harmful chemicals pose grave danger to consumers.
In response to Daily Trust inquiry, the Head of the Public Relations Unit of FCCPC, Mr. Ondaje Ijagwu, said the Commission had been mounting regulatory measures to protect consumers from badly preserved beans.
"FCCPC recognises the grave danger posed to consumers by the use of sniper and other harmful chemicals to preserve beans. As such the Commission strongly advocates for a joint regulatory initiative to find a lasting solution to the menace," he said.