Giving fruit buyers the pip
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Cape Town - Polluted rivers in deciduous fruit-growing areas could result in consumers having to pay more for local fruit and wine.
A Council for Scientific and Industrial Research (CSIR) study has calculated that polluted river water costs the deciduous fruit industry R98-million a year and the wine grape industry R188m a year.
These costs could be passed on to consumers.
Irrigation farmers drawing water from the Berg River and its tributaries have been concerned about the polluted river for years.
The CSIR was asked to find a solution to algae, just one of the pollutants in South African rivers. Quantifying the monetary costs of algae to deciduous fruit farmers is the first step in a 10-year study.
CSIR economist Willem de Lange, one of the team of scientists, said the request for help had come from the industry and the Department of Science and Technology had funded it.
“This is a long-term study and we’re monitoring all pollutants. There are data loggers all over the river and we can trace pollutants back to origin.”
De Lange, who published the findings in the Water Research Commission magazine Water Wheel, calculated that the costs to the industry amounted to 3.1 percent of the pre-harvest costs for plums and 5.2 percent for wine grapes. He said while these percentages may appear small, they were in fact “substantial” in an industry that had extremely small profit margins for producers.
“It is likely that these impacts could be given through to consumers, which could imply that consumers pay more for their fruit if nothing is done to curb the impacts of pollution,” De Lange said.
The study was done on water from the Dwars River, a tributary of the Berg. Although algae does not pose a direct threat to the crops, it costs the farmers because it clogs irrigation equipment.
This not only decreases the volume of irrigation water, but increases costs of maintenance on equipment. If it is not cleaned frequently, the lower or uneven irrigation water could affect crop yield.
The study looked at the amount of time staff had to spend cleaning equipment because of algal clogging, the cost of electricity, servicing and labour. This was calculated for times when the irrigation water had low and high algal loads.
Now that the costs have been quantified, it has created a budget for an algae management strategy that will be financially worthwhile.
Part of the reason for the high algae loads is increased amounts of nutrients, particularly phosphates.
Agrologist Francis Yeatman said yesterday some of the phosphates came from high amounts of fertilisers used in agriculture, and some from sewerage works not properly functioning.
“A problem is ‘recipe farming’, where a maize farmer simply applies a standard blend and quantity of fertiliser, instead of doing soil samples and identifying what the crop needs and applying only that. Instead fertiliser is being poured on to the land, in many cases unnecessarily, and it is contributing to algal blooms in rivers,” Yeatman said.
The other big cause came from soaps and detergents.
“The biggest user of phosphates in South Africa is the detergent and soap industry,” he said.