Precautions with Pesticides:
Protect the Environment

NOTE: Some materials available here are in PDF (portable document file) format. To read them you need the FREE Acrobat Reader installed on your computer. The program is available for download (with installation instructions) at http://www.adobe.com/products/acrobat/readstep2.htm.

Table of Contents

1. Prevent Contamination of Adjacent Land and Water Bodies
2. Buffer Zones
3. Protect Water Sources
4. Preventing Groundwater Contamination
5. Reduce and Manage Pesticide Spray Drift
6. Prevent Bee Poisoning
7. Other topics on Precautions with Pesticides
   • Pesticide Regulations
   • Certification and Training Requirements
   • General Precautions
   • Read and Follow Pesticide Label Information
   • Human Health
   • Protective Clothing and Equipment
   • Protect the Environment
   • Disposal of Pesticides and Empty Pesticide Containers
   • Storing Pesticides
   • Pesticide Spills
   • Application Procedures
   • Precautions with Pesticide Tables
     • Pesticide Schedules in Ontario (Pesticide Regulations)
     • Safety Supply Companies in Ontario Providing Protective Clothing & Equipment (Table 1-1)
     • Pesticides Act Storage Requirements (Table 1-2)
8. Related Links

Prevent Contamination of Adjacent Land and Water Bodies

Do not allow pesticides to drift, run off or leach onto land or water bodies bordering treatment areas. Leave a suitable buffer zone between the treatment area and adjacent areas. No spray droplets should fall on adjacent properties, where treatments are not authorized. Areas of concern are:

• cultivated plants grown for human consumption
• plants sensitive to herbicide drift
• trees or shrubs that may be damaged by herbicides leaching to roots
• areas where children play

Buffer Zones

Buffer zones are vegetated areas, left untreated to protect an adjacent area, for example a pond, a stream, a sensitive crop, a non-target crop, wetland or woodland, etc.

Setback Distances for Water Bodies

It is an offence under the federal Fisheries Act to introduce any material into water that may be harmful to fish or fish habitat. To protect these waters, landscape applicators must determine a suitable setback distance between the area to be protected and the area where pesticide treatments are planned. The protected area includes the water body, as well as adjacent riparian (riverbank) areas that contribute to fish food and habitat.

Protect Water Sources

• You must use an anti-backflow device to prevent back siphoning when drawing water from wells, ponds, streams or other sources.
• Mix pesticide and load the sprayer away from any water supply, including wells, ponds or streams.
• Use buffer zones (untreated areas) when you apply pesticides to avoid contaminating surface water, wells, ponds and/or streams. Check the product label for specific buffer zone distances.
• Do not allow equipment rinse water and excess pesticides to run into sewers, drains or ditches with water in them. Rinse water should be put into spray tanks and applied to the treatment area. Otherwise, it must be disposed of as hazardous waste through a hazardous waste disposal company. For more information, see the section Disposal of Pesticides and Empty Pesticide Containers.

Preventing Groundwater Contamination

Groundwater is the source of water for wells and springs. If groundwater becomes contaminated with pesticides, it is difficult to clean. Preventing groundwater contamination is crucial. Some pesticides have the potential to leach through the soil to groundwater.

Movement of pesticides into groundwater can make the water unfit for use. However, pesticides applied to the soil are subjected to physical, chemical and biological processes that affect their movement through the soil and their potential for groundwater contamination. Making the right pesticide choices for the situation can help minimize the threat of groundwater contamination.

Soil Characteristics

Soil texture plays a major role in pesticide performance and persistence. Soil organic matter can make a difference in pesticide activity. Therefore, it is important to select a pesticide based on soil type and organic matter content. Chemicals tend to leach more readily in coarse-textured soils with low organic-matter content. In contrast, fine-textured soils with high organic matter are highly adsorptive and therefore have a low leaching potential.

Pesticide Characteristics

Some pesticides bind strongly (adsorb) to soils and therefore are not easily removed. Clay materials and organic matter favour strong adsorption. Use soil analysis information on organic matter content when selecting pesticides and application rates for your pest management program. Some pesticides are highly soluble in water, which can increase their leaching potential. Leaching of a pesticide can be minimized by pesticide dosage and by the timing and method of application. Choose the right pesticide for your situation.

The rate of degradation by natural processes is highly dependent on both the pesticide class (chemistry) and environmental factors. Sunlight, temperature, soil, pH, microbial activity and other soil characteristics affect the breakdown of pesticide. Some pesticides break down slowly and therefore have a greater potential for leaching. A short-lived pesticide may be degraded before any leaching occurs. Choosing a short-lived pesticide can minimize leaching potential.

Microbial degradation occurs when fungi, bacteria and other soil microorganisms use pesticides as a food (energy) source. High organic-matter content, along with other properties such as optimum moisture, aeration, temperature and soil pH, can enhance microbial degradation. In addition, chemical degradation of pesticides can occur by reaction with water, oxygen and other chemicals. In general, pesticides that are highly water-soluble, relatively persistent and not readily adsorbed by soil have the greatest potential for leaching.

Water Table

High water tables may be vulnerable to contamination by pesticides and fertilizers due to the relatively short distance between the soil surface and groundwater. There is potential for groundwater contamination in areas with coarse-textured soils and high water tables.

Specific application information for each pesticide is contained on the pesticide label. Careful adherence to application and disposal directions, combined with proper equipment calibration, provide the best method of preventing groundwater contamination.

| Top of Page |

Reduce and Manage Pesticide Spray Drift

• Read the product label for information regarding buffer zones, water volumes and recommended
  nozzles.
• Use buffer zones around all watercourses and wells as well as neighbouring fields that contain sensitive crops. If the label does not state a specific buffer zone distance, leave an untreated area of natural vegetation.
• Select the recommended sprayer application rate (L/ha).
• Select the correct nozzle. Where practical, use air induction/venturi nozzles. These nozzles significantly reduce drift when compared to conventional nozzles.
• Select the correct nozzle-to-target distance.
• Spray only when winds are light to moderate (11 km/hr or less). If you notice drift is occurring because of the wind, stop spraying until the wind subsides. Do not apply pesticides if the wind is blowing towards susceptible crops or environmentally sensitive areas such as watercourses.
• Use spray plume protection where practical or available (hoods, shrouds, screens and air curtains).
• Use drift-reducing adjuvants in the spray tank as directed by the label.
• Utilize wick weeders, instead of spraying, when possible.
• Use non-volatile compounds

For more information about spray drift consult:

• OMAFRA/Agriculture and AgriFood Canada Best Management Practices booklet:
  • Pesticide Storage, Handling and Application
• Ontario Pesticide Education Program (Ridgetown College) videos:
  • How to Manage Spray Drift
  • Spray Drift Reduction through Air Induction.

| Top of Page |

Prevent Bee Poisoning

It is important to protect bees when you spray. Honeybees, as well as other bees and insects, are important pollinators of crops. Many crops also offer bees important sources of pollen for honey production.

If you choose to use insecticides for insect control, take these steps to prevent harming bees when you spray:

• Before you apply a pesticide, advise local beekeepers so that they can move colonies out of the danger area. Contact the Provincial Apiarist at 1-888-466-2372 for a list of the beekeepers in your area.
• Do not spray any flowering crop on which bees are foraging. If you must apply insecticides, spray after 7 p.m. when the bees are not foraging. If this is not a possibility, spray before 7 a.m. Bees usually do not forage at temperatures below 13°C.
• Do not apply insecticide on windy days to prevent drift toward any nearby hives.
• When there is a choice, choose the product formulation that is less hazardous to bees. Dusts are more toxic than sprays. EC formulations are less toxic than WP formulations.
• Under the Bees Act it is an offence to spray in orchards while there is bloom on the trees.
  Most organophosphate and carbamate insecticides are highly toxic to bees.

Table 1-5: Relative Toxicity of Insecticides to Honeybees

Unusually low temperatures at time of application may cause insectides to remain toxic up to 20 times longer than during warm weather. High temperatures in the early morning or late evening may extend active foraging by bees.

| Top of Page |

Related Links

• Publication 75, Guide to Weed Control
• Publication 812, Field Crop Protection Guide
• PMRA website

| Top of Page |