Pesticides report 34. Pesticide runoff: Methods and interpretation of field studies (Technical Report)

Abstract

Republication of this report is permitted without the need for formal IUPAC permission on condition that an acknowledgement, with full reference together with IUPAC copyright symbol (0 1995 IUPAC), is printed.Publication of a translation into another language is subject to the additional condition of prior approval from the relevant IUPAC National Adhering Organization. Synopsis The objectives, design and interpretation of experimental measurements of pesticide losses in rainfall induced runoff from the surfaces of agricultural fields are reviewed. Microplot-and Mesoplot-scale experiments, which use artificial rainfall, and field-and watershed-scale experiments, which use natural rainfall, provide different but complementary information. The smaller-scale experiments are more controlled, replicable and easier to undertake but cannot represent those processes which vary over larger scales; thus they may not be representative of many real situations. Larger-scale field and watershed monitoring experiments provide realistic runoff concentrations, but they are more difficult and expensive. Because rainfall is uncontrolled, they are likely to provide unrepresentative data which are difficult to interpret and to extrapolate to other field and weather scenarios. A risk-of -runoff assessment of a pesticide may require information from a combination of these tests, together with the use of computer simulation modeling to integrate the results. CONTENTS CONCLUSIONS AND RECOMMENDATIONSThe goals and uses of the different experiments are well unde rstood The me t hods for t hese studies are well-developed J n t e m r m 'on of these studies. and the strendhs and w e h s s e s of each Recommenda tions for future research Scale. are unders tood

Field and Laboratory Dissipation of the Herbicide Fomesafen in the Southern Atlantic Coastal Plain (USA)

“…Surface runoff results were in agreement with numerous published studies with peak pesticide concentrations observed during runoff events closest to application and with concentration decreasing exponentially as DAT increased . Findings were also consistent with the behavior of three other preemergence herbicides, pendimethalin, metolachlor, and fluometuron at the study site. ,, In each case, runoff mass loss was more than 10-fold greater from the CT versus the ST plots.…”

Simple, Rapid and Sensitive Electrochemical Method for the Determination of the Triketone Herbicide Sulcotrione in River Water Using a Glassy Carbon Electrode

“…They belong to the triketone class and present acidic properties (p K a of about 3) which are determinant for their environmental behavior as well as for the analytical method development itself. Generally, several processes are responsible for the off‐site transport of pesticides to surface waters; surface runoff, spray drift and leaching are examples 4, 5. Indeed, natural waters are frequently exposed to exceeding pulse concentrations of pesticides, which makes the quality status of aquatic ecosystems and water resources a permanent issue.…”

Foliar and Soil Deposition of Pesticide Sprays in Peanuts and Their Washoff and Runoff under Simulated Worst-Case Rainfall Conditions

“…For this reason, the convenience and control of using simulated rainfall on small plots makes it an attractive option and an accepted technique for chemical runoff studies. Rainfall simulation allows investigators to readily create the “reasonable worst-case” weather conditions needed for risk assessment ( , ). “Mesoplot”-scale runoff studies (plot size between 200 and 500 m 2 ) are being submitted to the U.S. Environmental Protection Agency by pesticide registrants as part of an environmental exposure assessment, and a few studies have been published ( − ).…”