MSI99P3225 | |
Ng Kee Kwong, K F Umrit, G Nowbotsing, M Gopaul, A K | |
Ground and surface water contamination by herbicide residues used in sugar cane fields in Mauritius | |
Periodical article | |
1999 | |
Sug.Cane | |
3: 14-18 | |
En | |
En | |
Residues of the nine herbicides, namely atrazine, diuron, hexazinone, 2,4-D, linuron, ioxynil, paraquat, oxyfluorfen and picloram, which are all used in weed control in sugarcane (Saccharum hybrid sp.) agriculture were monitored at fornightly intervals during 1995 and 1996 in ground and surface waters in Mauritius. The groundwater came from 20 boreholes representing the 10 main groundwater basing of Mauritius while the surface water was sampled at 25 locations along rivers forming part of the Grand River North West catchment area. The data showed that only the residues of atrazine, hexazinone and diuron could be detected in the freshwater sources in Mauritius. More than 60 percent of the groundwater samples analysed (> 50 percent for river water) in fact did not contain any detectable level of herbicide residue. Even when present, the levels of the residues were mostly within ghe range of 0.05 to 0.5 ppb with their highest recorded concentrations rarely exceeding the maximum limits of 3 ppb atrazine, 14 ppb diuron and 210 ppb hexazinone recommended for drinking water sources in the 1991 Environment Protection Act of Mauritius or by the United States Environment Protection Agency. The frequency of appearance of the herbicide residues varied from site to site and was not related to the piezometric depth of the groundwater basin. High rainfall events had a greater impact than time of herbicide application on the appearance of herbicide residues in the ground and surface waters. The present study therefore showed that no freshwater source in Mauritius is sheltered from possible contamination by these herbicides. The public fear and mistrust of herbicides are however not justified as the level of herbicide residues in the water does not in general pose a risk to human health. | |
sugarcane herbicides weed control water pollution pollution atrazine diuron hexazinone 2,4-D linuron ioxynil paraquat oxyfluorfen picloram | |
Mauritius | |
Environmental management | |
Agrochemicals movement | |
1999-08-04 | |
En | |
Mauritius Sugar Industry Research Institute, Agricultural Chemistry Department, Réduit, MU | |
CAT | |
CHEM |