Dispersion Of Pesticides

Below: chemicals can evaporate into the air very easily.
Improper settings on a sprayer can increase the risk of this.

Ways that pesticides spread in the environment

The airborne movement of pesticides to non-target areas is commonly called "drift" and may damage other crops, livestock, humans and beneficial insects. The main factors responsible for drift are the wind and the spraying equipment. Applying chemical pesticides on a windy day with poorly adjusted equipment (pump pressure, droplet size, spray height, choice of nozzles, etc.) can lead to an excessive amount of pesticide material not reaching the ground and being carried away to a non-intended location.

Pesticides can volatilize into the atmosphere from the surface where they have been applied.

Pesticides can travel with surface water runoff. When there are heavy rains in the two first weeks following the application of pesticides, they can be transported by the water and soil particles they become attached to. This movement of pesticides can also be occur during the snowmelt period in spring. Therefore, soil conservation measures are an integral part of preventing watercourse contamination by pesticides.

Pesticides can penetrate down into the soil profile until they reach the underground drains or water table. Soil type, organic matter content, pH, humidity, biological activity and the capacity of soil particles to retain the pesticide material all influence the infiltration of the pesticide in the soil and the degree of contamination.

The accidental dumping or spillage of pesticides during mixing and filling operations or during transport, the emptying out of pesticides from application equipment and cleaning up after use, greatly increases the chance of these materials ending up in ground or surface water if proper procedures are not followed.

Below: pesticides can reach far-off destinations if not properly controlled.

Consequences of pesticides dispersion

Pesticides can damage crops that are sensitive to the designed action of the material; this occurs mainly with herbicides. They can also contaminate a crop ready for harvesting (the presence of pesticide residues can disqualify a product from being brought to market).

They can contaminate a potable source of water, streams and rivers, becoming harmful to fish and other organisms living in the aquasystems.

They can contaminate the people living around the application sites, as well as the surrounding environment. They can also contaminate and make unusable an irrigation pond or well.