Volatilization of the pesticides chlorpyrifos and fenpropimorph from a potato crop.

Volatilization of pesticides from crops in the field can be an important emission pathway. In a field experiment with characterization of meteorological conditions, the pesticides chlorpyrifos and fenpropimorph were sprayed onto a potato crop, after which concentrations in the air and on/in the plants were measured. Rates of volatilization were estimated with the aerodynamic profile (ADP), energy balance (EB), relaxed eddy accumulation (REA), and plume dispersion (PD) methods.

Measured and computed volatilisation of the fungicide fenpropimorph from a sugar beet crop.

Depending on their vapour pressure, volatilisation can be one of the main pathways of emission of pesticides into the environment. The volatilisation of fenpropimorph was studied in a field experiment in which the fungicide was sprayed onto a sugar beet crop. Volatilisation rates were calculated by measuring the concentration gradient in air, using the Aerodynamic and Bowen Ratio methods.

Preferential flow of bromide, bentazon, and imidacloprid in a Dutch clay soil.

Leaching to ground water and tile drains are important parts of the environmental assessment of pesticides. The aims of the present study were to (i) assess the significance of preferential flow for pesticide leaching under realistic worst-case conditions for Dutch agriculture (soil profile with thick clay layer and high rainfall) and (ii) collect a high-quality data set that is suitable for testing pesticide leaching models. The movement of water, bromide, and the pesticides bentazon [3-isopropyl-1H-2, 1,3-benzothiadiazine-4(3H)-one-2,2-dioxide] and imidacloprid [1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine] was monitored in a clay soil for about 1 yr.