A first assessment of glyphosate, 2,4-D and Cry proteins in surface water of South Africa
Abstract
Agriculture plays a vital role in the South African economy, as well as in the production of maize for
food. Genetically modified maize is transformed to encode for crystalline (Cry) proteins found in Bacillus
thuringiensis (Bt) and is referred to as Bt maize. Ingestion of specific Cry proteins causes the death of
target insects that cause harm to maize plants. Bt crops, along with herbicides such as glyphosate and
2,4-dichlorophenoxyacetic acid (2,4-D), are widely adopted as part of the South African farming regime that
aims to increase crop yield and reduce costs of production. As chemical compounds used in agriculture often
end up in water sources, their presence should be monitored. There are many such monitoring programmes
worldwide, but not in South Africa. We screened surface water sources in a maize-dominated agricultural
area in the North West Province in South Africa for the presence of Cry1Ab, glyphosate and 2,4-D using
enzyme-linked immunosorbent assays (ELISAs). Cry1Ab was not detected at any site; glyphosate was below
the limit of detection at most of the sites but one sample had quantifiable traces of glyphosate; and 2,4-D was
detected at all the sites. The concentrations of 2,4-D exceeded those for drinking water according to European
guidelines, thus highlighting the need for regular monitoring of these compounds. Many people depend on
untreated water resources, which may be contaminated by toxic agricultural chemicals. This report is the first
on levels of these target compounds in South African water systems
URI
http://hdl.handle.net/10394/33520https://www.sajs.co.za/article/view/5988/8888
https://doi.org/10.17159/sajs.2019/5988