Recent tests carried out by the Zimbabwe Organic Producers and Promoters Association (ZOPPA) and UK-based NGO Garden Africa on fresh produce available in Harare have found a cocktail of pesticide residues. Individually the pesticides are not over the maximum residue levels but the organisations believe the findings should still be of interest for consumers in the city.

The persistence of a pesticide in the ecosystem and the dose or rate of application will determine how much pesticide remains in food at the time of harvesting or point of sale. These traces of pesticides, which remain in food at the time of sale, are referred to as pesticide residues.

Samples of tomato, carrot, okra, cabbage and fine beans were collected from three Harare supermarkets and Mbare Musika to give an indication of chemicals that are routinely used in agricultural production, and marketed in and around Harare.

The results, even of this small sample taken during a low pesticide-use period, found four pesticide residues, three of which were found in one sample. Of the four pesticides found, one is classified as a high-risk hazard by the WHO, and another is listed by the US Environment Protection Agency for testing for suspected endocrine disruption. All are carcinogens, with development and reproductive toxicities. One contains a highly toxic compound causing neurological toxicity. The pesticides found were the two insecticides Flubendiamide and Imedacloprid and the fungicides Tebuconazole and Boscalidnicobife.

A similar but more in depth FAO study of tomatoes and kale in Bulawayo, collected and analysed over three seasons, found that only 8% of the tomato samples did not have any chemicals, 46% had one chemical, 8% had two chemicals, 15% had three chemicals, 15% had four chemicals and 8% had nine chemicals. For kale, 9% of samples had one pesticide residue detected, 30% had two pesticide residues detected, 39% had three pesticide residues detected, 17% had four pesticide residues detected and 4% had five pesticide residues detected.

Research is increasingly finding that, even if within acceptable levels as a single compound, pesticide cocktails dramatically increase toxic effects. The question is what is the impact of multiple usage on human health and why isn’t this being tracked in the food chain?

These findings come contrary to the common belief among the general populace that fruit and vegetables in Zimbabwe are largely organic, i.e. grown without pesticides. There are a number of distinctions between conventionally grown crops and those that have been produced organically. The latter does not allow the routine use of chemicals, which include the pesticides listed above. Zimbabwean producers have a huge role to play in safeguarding human health.

The point of the study was not to discourage consumers from eating their 3-a-day of fresh produce, but rather to encourage them to find out where their food is coming from and to know what they are eating.