Cocktail of pesticides in vegetables – study

As soon as the plants sprout, Augustine Otim, a resident of Pugwinyi village, Gwengdiya Parish, Awach Sub-county in Gulu District, starts spraying his half-acre tomato garden, sticking religiously to 7 to 10- day intervals.

In a bid to earn north of Shs10 million from his harvests, Mr Otim always pushes the envelope. This is not just when it comes to tilling the land. He uses five spoonfuls of a powdered fungicide known as Mancozeb instead of the recommended three. Infections, he tells Saturday Monitor, are stubborn.

“If you put more, you are sure to get rid of them completely,” he reasons.

A stone’s throw away, a half-acre green pepper garden belonging to Raymond Ocira also generously uses the fungicides, Profenofos and Cypermethrin. Mr Ocira says the wet conditions that were prevalent in May and early June “aid[ed] pests and both viral and fungal infections on vegetables.”

With an annual growth rate of 20 percent, horticultural production is quite popular in Uganda. Tomato and green pepper farming have proven to be handy cash cows. Large quantities of pesticides have, however, fuelled their growth.

Empirical evidence shows that these pesticides pose long-term health effects such as predisposing people to cancer, especially when used carelessly.

Globally, there are more than 1,000 pesticides used to prop the food chain. Each pesticide has different properties and toxicological effects.

The Uganda National Association of Community and Occupational Health (UNACOH) for instance recently indicated that horticultural farmers in Uganda use up to 45 highly hazardous pesticides to boost crop production.

The 2022 UNACOH report noted that tomatoes were the horticultural crop most doused in pesticides.

“When we peeled the tomatoes and took off the outer skin, a lot of the chemicals remained on the peelings. It reduced the chemical concentration on the tomatoes by 69.7 percent. Washing with warm water reduced it by about 38 percent and with cold water by 30 percent,” Mr Aggrey Atuhaire, the agricultural component coordinator at UNACOH reveals, adding that they worked with about 400kg of tomatoes from 30 farms and 41 markets dotting four regions of the country.

Tomato toxicity

In the four specimens, Mr Atuhaire said  they found eight different chemicals. Mancozeb, he added, “had the highest concentration” followed—in no particular order—by Malathion, Profenofos, Cypermethrin, Lambda-cyhalothrin, Metalaxyl, Chlorpyrifos and Dichlorvos.

In western Uganda, while all samples collected from four markets in Ntungamo and Kamwenge exhibited chemical levels within the normal range, samples collected from two markets in Masindi exhibited chemical levels extremely above normal.

In the eastern districts of Budaka, Bugiri, Kumi, and Pallisa, samples collected from five of the 10 markets exhibited contamination levels above the normal range. Ditto the central region where samples from markets like Nakasero, Kalerwe, Nakawa, and Kasubi exhibited abnormal levels of contamination with chemical residues.

In the north, samples from Adjumani, Nebbi, Gulu, and Kitgum districts had the highest concentration of chemical residues compared to the rest of the regions.

What next?

To address the problem, the researchers recommended that the government spearheads efforts to establish pesticide waste management and disposal plans. A pesticide residue monitoring plan for drinking water and food in all districts should be set in motion, they further recommended.

By 2020, up to 41 highly hazardous pesticides had been legally registered for sale and use in Uganda. Of the 41, insecticides were the most widely applied pesticide (51.1 percent) followed by herbicides (21.3 percent) and fungicide (12.8 percent).

More than 80 percent of pesticides sold in Uganda fall under GHS 1a and 1b categories marked by the World Health Organisation to be highly hazardous pesticides with acute toxicity, carcinogenicity, mutagenicity, and reproductive toxicity.

In August 2022, Makerere University scientists unveiled software to protect consumers from toxic chemicals in food that can cause cancer, brain disease and other complications.

Using the software dubbed Kebera Organics, a consumer can only scan the food commodity and get either of the three signals: red, yellow or green.

Red means it’s dangerous, yellow means the contamination is at a moderate level and green means it is safe.

In a 2022 report, the United Nations Environment Programme (UNEP) highlighted the need for transformative actions and better management of pesticides as global demand and use increases.

“Focusing on methodologies, tools, approaches and policies that directly strengthen pesticide management, to minimise the adverse effects to our health and the environment, is key for a sustainable, safe, clean future for all,” it stated.

Govt responds

The global demand, production and use of pesticides have expanded steadily during the past decades, with the combined global sales values continuing to annually grow at about 4.1 percent.

The outlook in Uganda keeps worsening. While the global organic market is worth $100 billion (Shs367 trillion), Uganda’s share of the market stands at just $50 million (Shs183 billion).

“If you walked into a market in Gulu City here randomly, you will find green pepper, tomatoes, eggplants, etc. smelling fresh with these chemicals,” Mr Cosmas Onen, the Gulu City health and safety officer tells Saturday Monitor, adding, “The problem is that the consumers also do not wash well these foods before eating yet the residues of such chemicals on the food exceeded European Food Safety Authority maximum residue limits and they get poisoned without knowing.”

Whereas the government is doing a lot of sensitisation among farmers on management and disposal of the chemical containers, Mr Paul Mwambu, the commissioner for crop inspection and certification at the Agriculture ministry, says consumers still pay the price of ignorance among farmers.

Mr Mwambu says: “The biggest challenge we have is that on each of the containers of pesticides there is a label explaining the danger, safety precautions, how to dispose of and the content of the pesticides, but some of our farmers may not know how to read and those who know how to read do not take care to read the instructions that are there.”

He adds: “Even where they read and understand, they do everything out of carelessness. The government cannot be everywhere, but it is all of us, the sub-county chiefs, parish chiefs, LC and once we realise that it is important, then each of us has a role to play.”

The Agriculture ministry also claims that they have now conditioned agro-input dealers who trade in the chemicals to collect the empty containers for proper disposal.

“We are compelling the dealers to make sure that the containers are collected. The other one is voluntary where the community comes up because of realisation of the dangers and they do the collection,” Mr Mwambu says.

After spraying, we even teach the farmers how to clean the residues in the bottle. After that, some of those highly hazardous containers should be collected and taken back to the manufacturers or distributors, he added.

He adds that dealers in agrochemicals are now being taken through the pesticide safe use training, which now requires anyone dealing in the business to hold a minimum of O-Level certificate to be able to guide the farmers.

“Others are also trained on the alternative ways of disposal. Some of these containers, if they are not safely kept away from the community, some households may use them to store things like salt, milk, sugar and even carrying water or food, which causes a very high risk to household members,” he says.

Water contamination

The researchers also examined how the chemicals contaminated water facilities used for domestic consumption.

They found exceedingly high levels of chemical residues from pesticides when they collected samples from 86 domestic water sources from 17 districts across the four regions.

The samples were collected at the start of the planting season in April 2018 and June 2018 when at the backend of the harvesting period.

In April, only seven chemicals were discovered in water sampled from the 86 water sources. By June the number of chemicals had spiked to 25.

Of all the 18 water sources sampled in the north (Gulu, Nebbi, Adjumani and Kitgum), the researchers discovered 13 chemical residues.

The east (Kapchorwa, Kumi, Palisa, Budaka and Bugiri) tallied 12 chemicals from 29 water sources; the west (Masindi, Kamwenge, Bushenyi and Ntungamo) 11 chemicals from 19 water sources; and the central region (Wakiso, Kayunga, Rakai and Sembabule) 11 chemical elements were detected in the 20 water sources that were sampled.

Of all the chemicals found in the water, Glyphosate had the highest concentration at 53 percent.

This was followed by Aldicarb (16 percent), Dichlorvos (15 percent), Atrazin (10 percent), and Chlorfenvinphos (six percent).

The report blamed the food and water contamination on overdosing of pesticides by farmers, and the indiscriminate disposal of empty pesticide containers, among others.

“Almost up to 44 percent of farmers were overdosing on the chemicals to achieve maximum results while more than 55 percent of the sampled farmers harvested the fruits immediately upon spraying,” the report reads in part, adding that exposure to multiple pesticides resulted in neurobehavioural outcomes among smallholder farmers in the sampled areas.