Recognizing and avoiding pesticide hazards. Susan Donaldson Water Quality Education Specialist

Transcription

1 Recognizing and avoiding pesticide hazards Susan Donaldson Water Quality Education Specialist

2 Pesticide residues are found in both surface and groundwater locally Pesticide registrations are affected by water quality contamination

3 Herbicides: Triazines simazine Atrazine deethyl atrazine prometon 2,4-D (phenoxy growth regulator) DCPA (Dacthal, preemergence herbicide ) Insecticides: Organophosphates diazinon malathion Carbamates carbaryl

4 143 different pesticides have been found in the groundwater of 43 states, affecting 100+ million people.

5 Toxic pesticides may render a well unsafe for use. Contaminated water can also cause crop injury and monetary losses. Remediation is costly and may take many years.

6 **atrazine (Aatrex ) tebuthiuron (Spike ) **simazine (Princep ) + bromacil (Hyvar ) **prometon (Pramitol ) + terbacil (Sinbar ) **deethyl atrazine diazinon (Spectracide ) + diuron (Karmex ) + silvex (Fenoprop ) In , the U.S. Geological Survey found very low levels of these pesticides in urban and rural shallow wells. ** most commonly found + associated with urban areas

7 Contact and residual herbicide Weed control in certain crops, industrial areas, rights of way DANGER (potential eye damage) From 2006 to 2010, detected in 22 samples from 6 wells located in Lyon and Douglas Counties

8 There are several ways that pesticides get into water. Drifting Dust Volatilization Pesticide Drift Aquatic Applications Chemigation Runoff Leaching

9 By air Vapor, particle, spray drift By water Surface runoff Movement through soil By other objects Residues on plants and animals WSU

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11 D R I F T

12 Certain products volatilize and move with airflow off-target under warm weather conditions (above 85 F) Check the label for precautions for cut-off temperatures Select low-volatile formulations WSDA

13 Dust applications can drift Certain pesticides attach to soil particles, remain active and can blow off-target Check the label for soil incorporation precautions WSDA

14 1. Applicator attitude 2. Equipment set-up o Spray coarseness 3. Viscosity of spray o Liquid s resistance to flow WSDA What happened here? 4. Weather conditions

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16 Diameter ( m) Appearance Time to fall 10 feet in still air 1 Fog 28 hours 10 Fog 17 minutes 100 Mist 11 seconds 200 Fine spray 4 seconds 400 Coarse spray 2 seconds 1000 Coarse spray 1 second

17 High temperatures Do not spray in temperatures exceeding 85 degrees F. Questionable over 80. Wind Do not spray in wind speeds >10 mph Humidity Inversions

18 Warmer air above cooler air

19 Can occur anytime Usually develops at dusk May continue through night Breaks up when ground warms up in morning It may appear ideal, but is not increases potential travel distance

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21 Spills and leaks Maintain an air gap into sewer at mix/load sites wash sites Backsiphoning when filling sprayer or chemigation Improper handling and disposal near water sources

22 Pesticides move in water over soil into surface water Contaminated ditches, streams, rivers, ponds, and lakes Surface water used for drinking and livestock water, irrigation, etc.

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24 grade or slope of the area soil texture vegetation soil moisture amount and timing of irrigation or rainfall pesticide characteristics

25 Guess where you re really putting your lawn pesticides this spring? From 3 Rivers Wet Weather

26 Movement of pesticide by water through soil Move horizontally to nearby roots or vertically toward groundwater

27 Geology how permeable is the soil? Soil texture and structure Sandy: fast percolation, few binding sites Silt, clay or organic matter: slower percolations and many binding sites Depth to groundwater: shallow water tables pose a concern Amount and timing of rainfall or irrigation

28 Soil surveys provide information on texture, permeability, and depth to groundwater. Example: Settlemeyer soil 510: 0-15 inches fine sandy loam (10-20% clay) inches silty clay loam and clay loam (27-35% clay) moderately slow permeability seasonal high water table at a depth of inches in late winter and spring

29 Solubility Adsorption Degradation and persistence Volatility

30 The ability of a pesticide to dissolve in a solvent, usually water Soluble pesticides are more likely to move with water in surface runoff or through the soil to groundwater

31 Pesticides that have a water solubility of greater than 30 ppm are classified as leachable. Pesticide Solubility (ppm) Pyrethrins Trifluralin 0.2 Malathion 130 Hexazinone 33,000 Glyphosate 900,000

32 Binding of chemicals to soil particles Clay and organic matter increase binding Decreases the potential for a pesticide to move through soil

33 Pesticide Triclopyr triethylamine salt (Brush-B-Gon ) K oc (ml/g OC) 20 Hexazinone 54 Carbaryl (Sevin ) 300 Malathion 1,800 Glyphosate (Roundup ) 24,000

34 Important means for destroying pesticides in soils Some soil microorganisms use pesticides as food source Bacteria, fungi, other organisms

35 warm soil temperatures aeration adequate soil moisture fertility favorable ph adsorption

36 Hydrolysis occurs at high ph Non-living processes Hydrolysis: a chemical reaction with water, typically with a high ph (organophosphates, carbamates) Soil properties and conditions affect the rate and type of chemical reactions

37 Breakdown of pesticide by sunlight Reduced by soil incorporation

38 Ability of a pesticide to remain present and active for a long time Provides for long-term pest control, but may harm sensitive plants and animals

39 T ½ Half life

40 Half lives non persistent -- less than 30 days moderately persistent to 100 days persistent -- greater than 100 days

41 Low Persistence (half-life <30 days) Pesticide Persistence in Soils Moderate Persistence (halflife days) High Persistence (half-life > 100 days) Aldicarb Aldrin Bromacil Captan Atrazine Chlordane Dalapon Carbaryl Lindane Dicamba Carbofuran Paraquat Malathion Diazinon Picloram Methyl Parathion Glyphosate Trifluralin 2,4-D Hexazinone Acie C. Waldron, Pesticides and Groundwater Contamination, Ohio State University Extension Bulletin 820, 1992 available at <

42 Occurs when pesticide surface residues change from solids or liquids to gases or vapors Once airborne, volatile pesticides can move long distances off site

43 Temperature Wind Humidity = Higher Volatility

44 Fumigants volatilize and move as gases through soil, structures or stored commodities Several herbicides are quite volatile and pose harm when the vapor moves off target Labels may state cut-off temperatures for application Labels may require pesticide to be incorporated into the soil

45 Herbicide Solubility (ppm) Half-life (days) Koc (ml/g) Leaching Potential 2,4-D acid medium dicamba 6, high glyphosate 90, ,000 very low metsulfuron 6, low picloram high hexazinone 33,000 ~90 54 high

46 1. Practice integrated pest management (IPM): Identify pests and verify a problem exists. Apply pesticides only when necessary. Use the lowest label rate that gives adequate pest control

47 2. Select pesticides carefully: Use pesticide properties to determine leaching and persistence potential. Read the pesticide label carefully for information and restrictions on the rate, timing and placement of the pesticide. Note any groundwater advisories or other water protection guidelines on the label.

48 RESTRICTED USE PESTICIDE (GROUND AND SURFACE WATER CONCERNS) THIS PRODUCT IS A RESTRICTED-USE HERBICIDE DUE TO GROUND AND SURFACE WATER CONCERNS. USERS MUST READ AND FOLLOW ALL PRECAUTIONARY STATEMENTS AND INSTRUCTIONS FOR USE IN ORDER TO MINIMIZE POTENTIAL FOR ATRAZINE TO REACH GROUND AND SURFACE WATER. GROUNDWATER ADVISORY Atrazine can travel (seep or leach) through soil and can enter groundwater which may be used as drinking water. Atrazine has been found in groundwater. Users are advised not to apply atrazine to sand and loamy sand soils where the water table (groundwater) is close to the surface and where these soils are very permeable, I.e. well drained. Follow all label directions Groundwater advisory MIXING/LOADING INSTRUCTIONS This product may not be mixed/loaded, or used within 50 ft. of all wells, including abandoned wells, drainage wells, and sink holes. Operations that involve mixing, loading, rinsing, or washing of this product into or from pesticide handling or application equipment or containers within 50 ft. of any well are prohibited, unless conducted on an impervious pad constructed to withstand the weight of the heaviest load that may be positioned on or moved across the pad. This product may not be mixed or loaded within 50 ft. of intermittent streams and rivers, natural or impounded lakes and reservoirs. This product may not be applied aerially or by ground within 66 ft. of the points where field surface water runoff enters perennial or intermittent streams and rivers or within 200 ft. around natural or impounded lakes and reservoirs. If this product is applied to highly erodible land, the 66-ft. buffer or setback from runoff entry points must be planted to crop, seeded with grass or other suitable crop. A 50-foot distance from well and water bodies is required

49 Before selecting a pesticide, use pesticide risk assessment tools. Win-PST: From UCIPM Website

50 3. Consider the vulnerability of the area: Check soil properties with the Natural Resources Conservation Service or your local Cooperative Extension office to determine the relative susceptibility of the soil to leaching. Determine the depth to groundwater if possible.

51 4. Consider the location and condition of wells: Wells should be properly capped and sealed to prevent groundwater contamination. Pesticides should not be mixed, stored or disposed of within 100 feet of a well.

52 5. Measure and calibrate accurately; mix and load carefully: Use only the necessary amount of pesticide. This will save you money! Check the equipment for leaks and malfunctions. Consider spray droplet size.

53 Photo courtesy of USDA-

54 Spray when wind <10 mph Know what is next door Use buffer zones Do not spray when air is calm (inversion)

55 6. Prevent back-siphoning: Air gap Antibackflow device Check valves on wells

56 Do not fill spray tanks near a wellhead. Photo courtesy of M.J. Weaver, pesticidepics.org (Virginia

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58 7. Consider weather and irrigation: Delay the application of pesticides if you expect heavy or sustained rain or you are planning a heavy irrigation. When applying chemicals through irrigation systems (chemigation), carefully control the quantity of irrigation water to minimize potential runoff or leaching.

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60 8. Store pesticides safely: Buy only what you need for a season or specific treatment. Locate the pesticide storage area away from all water sources and construct with a concrete floor. Inspect containers regularly for leaks.

61 Dispose of pesticide containers properly

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63 9. Prevent spills: If a spill occurs, contain it and clean it up immediately. Continual spills of pesticides in the same area can overload the capacity of the soil to break them down.

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65 10. Leave buffer zones around easily contaminated areas: Establish a buffer zone between a pesticide use or handling site and a sensitive area near springs, streams, wetlands, wells or other water bodies by planting vegetation or leaving an untreated border in the field.

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68 Contamination MORE likely High pesticide use High recharge (rainfall or irrigation) High soil permeability No confining clay layers Dug or driven wells Shallow wells Wells with leaky seals Low pesticide use Low recharge Low soil permeability Bedrock Thick confining layers Drilled wells Deep wells Wells with proper seals Contamination LESS likely

69 Protect sensitive areas Protect non-target organisms Pollinators, beneficials Fish, livestock, and wildlife Protect endangered and threatened species

70 Sue Donaldson