Electroanalytical procedure and sorption studies for imazaquin in different soils

ABSTRACT

The objective of the present work is to determine sorption coefficients of the herbicide imazaquin using the differential pulse polarography in the major soil classes occurring in the State of São Paulo, Brazil. This study contributes to the predictions of pesticide fate and transport mechanisms in the environment as well as its exposure and interactions with different soil materials. Imazaquin was analysed directly in soil samples (scan rate 2 mV s^–1, mercury drop size 0.37 mm, and pulse height 50 mV) and the detection limits varied from 42 to 58 g L^–1 for different soils. Imazaquin showed the K_F values varying from 0.8 (for the sandy soil) to 35.5 L kg^–1 (for the medium textured soil), with a significant dependence on the soil pH, organic matter content, and clay minerals. The study demonstrates the practical utilisation of the electroanalytical methodology to determine the imazaquin adsorption in soil and consequently assess the impact of this herbicide in the environment, especially for the evaluation of the potential risk of surface and groundwater contamination.

KEYWORDS:

• Differential pulse polarography
• imazaquin
• sorption
• tropical soils

Acknowledgements

The authors thank the financial supports from the Brazilian Agricultural Research Corporation (EMBRAPA), the Brazilian National Council for Scientific and Technological Development (CNPq) under grant no. 550188/2002-9 (CT/Hidro), 132144/2002-6 and 304951/2013-7 and University of Macau Multi-Year Research Grant and Macau Science and Technology Development Fund (MYRG2014-00112-FST and FDCT/063/2013/A2).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors thank the financial supports from the Brazilian Agricultural Research Corporation (EMBRAPA); the Brazilian National Council for Scientific and Technological Development (CNPq) [grant number 550188/2002-9], (CT/Hidro) [grant number 132144/2002-6], and [grant number 304951/2013-7]; and University of Macau Multi-Year Research Grant, and Macau Science and Technology Development Fund [grant number MYRG2014-00112-FST], and [grant number FDCT/063/2013/A2].