Wetenschap - 31 januari 2002

Ghanese eat contaminated vegetables

Ghanese eat contaminated vegetables

Ghanese people are not worried about their health when they buy their vegetables on the market. The vegetables look very good, says MSc student Bernard Keraita, who graduated this week. But he believes that this beauty is only skin-deep. In reality many vegetables are irrigated with highly contaminated water and thus pose considerable health risks.

Keraita, who is from Kenya, went to Ghana to do research for his MSc in Soil and Water. There he investigated the use of waste water by farmers, probably the cause of many health problems in this country. "A lot of untreated waste water from towns and villages flows into the rivers, and farmers use this water to irrigate their crops."

You can't detect the contamination by looking at the vegetables, says Keraita. "As the waste water that is used is full of nutrients, the ripe vegetables will usually look very good. What you can't see are all the unhealthy pathogens in the tissue of the vegetables."

A major problem in Ghana is that there are very few facilities for waste water treatment. In the second largest city Kumasi there are two big sewage plants but only one operates. At least half of the city's waste water flows directly into the environment. "The technology of the sewage plants is too complex for the Ghanese. Western engineers install them but when they are gone and the system breaks down, nobody is able to correct it. There is also no money to replace broken components."

Ideas

How can the Ghanese people reduce the health risks with minimal effort? Keraita has some ideas. He believes farmers should wait with harvesting for at least two weeks after irrigation. Most pathogens in the water will not survive in the crops for so long, he thinks.

Also, many farmers can reduce irrigation, Keraita believes. "Many have very small plots that do not require much work, so having nothing else to do, they tend to irrigate the whole day." The problem is that farmers do not really care about the health risks of their crops, says Keraita. The only other option then is for the buyers to remove the outer leaves of the vegetables, reducing the health risk, but not completely.

Hugo Bouter

Re:ageer