Assessment of imazapic presence in surface water and groundwater in paddy field area

Abstract

Herbicide is a well-known artificially synthesized substance used in paddy fields as an effective way to increase the quantity and quality of rice production by controlling the weedy rice in the field. In Tanjung Karang area, a new paddy strain was introduced to avoid weedy rice problem which requires farmers to apply herbicide containing imazapic and imazapyr which kills the weedy rice only but does not affect the new paddy strain. However, imazapic has the possibility to cause several health problems and also disrupting aquatic ecosystem. Hence, this research aims to carry out an extraction procedure and detection for imazapic residues in surface water and groundwater to assess its distribution in the study area. In this study, samples were collected from the surface water and groundwater for two consecutive seasons of paddy cultivation. After several clean-up and extraction procedure using solid-phase extraction (SPE) method, the water samples were analyzed using High Performance Liquid Chromatography-UV (HPLC-UV) for the presence of Imazapic residue. In 52.6% of the surface water samples and 51.8% of the groundwater samples, presence of imazapic residues was detected. This is a concern as it may possibly cause harm to the farmers. Results showed significant difference for the level of imazapic concentration detected in surface water during main season and off season (p-value=0.005, CI = - 0.39, 0.11). Thus, it can be concluded that the concentration of imazapic residue detected during main season (o.71 ug/ml) was higher compared to the samples collected during off season (0.57 ug/ml).