Environmental Effects of Pesticides Stephen J. Toth, Jr. Wayne G. Buhler Department of Entomology Department of Horticultural Science North Carolina State University North Carolina State University Photograph by Ken Hammond.

What is the Environment? The “environment” is everything around us natural and manmade; not limited to the outdoors, but including indoor areas in which we live and work. Erwin W. Cole Ken Hammond

How do Pesticides Effect the Environment? Point-Source Pollution: contamination that comes from a specific, identifiable place (a point) Includes pesticide spills, wash water from cleanup sites, leaks from storage sites, and improper disposal of pesticides and their containers Tim McCabe

How do Pesticides Effect the Environment? Nonpoint-Source Pollution: contamination that comes from a wide area Includes the drift of pesticides through the air, pesticide run- off into waterways, pesticide movement into ground water, etc. Bob Nichols

Environmentally-Sensitive Areas Sensitive areas include sites or living things that are easily injured by pesticides, including: areas where ground water is near surface or easily accessed through wells, sinkholes, etc. areas near surface waters (oceans, lakes, streams) NCSU Communication Services

Environmentally-Sensitive Areas Sensitive areas include sites or living things that are easily injured by pesticides, including: areas heavily populated with people (schools, playgrounds, hospitals, nursing homes, etc.) areas populated with livestock and pets Ken Hammond

Environmentally-Sensitive Areas Sensitive areas include sites or living things that are easily injured by pesticides, including: areas near the habitats of endangered species and other wildlife areas near honey bees areas near food crops and ornamental plants Steve Bambara

Environmental Impact of Pesticides in Air The atmosphere is an important part of the hydrologic cycle Pesticides enter the atmosphere through drift, wind erosion and evaporation Pesticides can move great distances in the atmosphere Pesticides reach the earth’s surface via dry deposition and precipitation U. S Geological Survey

Environmental Impact of Pesticides in Air Long-range movement of long-lived pesticides documented: DDT and other organochlorine pesticides detected in Arctic and Antarctic fish and mammals; used in 1960s and 1970s Toxaphene is still transported into Great Lakes region by winds from the Gulf of Mexico; used on cotton in the South, banned in 1982 USDA/ARS

Environmental Impact of Pesticides in Air Pesticides frequently detected in the atmosphere: Organochlorine insecticides (DDT, dieldrin and lindane): widespread use in 1960s and 1970s; resistant to environmental degradation Organophosphate insecticides (chlorpyrifos, diazinon, malathion and methyl parathion): not long-lived in environment; used heavily in the past and at present Triazine herbicides (atrazine): heavily-used herbicides, persistant in environment Acetanilide herbicides (alachlor and metolachlor): used heavily, but not as persistant as triazine herbicides

Environmental Impact of Pesticides in Air Number of pesticides detected in air, rain, snow and fog. U. S. Geologic Survey (1995).

Environmental Impact of Pesticides in Air Hazards of atmospheric pesticides to humans and environment: Source of exposure to pesticides through inhalation (lungs have surface area equal to tennis court) Source of contamination of surface waters and ground water through dry deposition and precipitation Transport of pesticides from application sites to sensitive areas Accumulation of pesticides in the environment (soil, wildlife, etc.) Gene Alexander

Environmental Impact of Pesticides in Soil Pesticides can move in the environment via the soil by two methods: erosion and leaching Erosion: soil particles which are transported by wind and water; pesticides attached to soil particles Leaching: downward movement of pesticides in the soil through cracks and pores USDA Photograph

Environmental Impact of Pesticides in Soil Leaching USDA Photograph Soil normally filters water as it moves downward, removing contaminants such as pesticides Soil and pesticide properties, geography and weather can influence the movement of pesticides (leaching) Pesticides that leach through soils may reach ground water

Environmental Impact of Pesticides in Soil Soil Properties That Affect Leaching Organic matter: plant and animal material decomposing in the soil; organic matter binds pesticides; the more organic matter in the soil, the less likely pesticides will leach Soil texture: determined by the percentage of sand, silt and clay; the higher percentage of sand, the more likely pesticides will leach USDA Photograph

Environmental Impact of Pesticides in Soil Soil Properties That Affect Leaching Soil acidity (pH): the acidity of the soil affects chemical properties of pesticides; as the soil pH decreases (becomes more acidic), pesticides bind more to the clay in the soil making the pesticides less likely to reach the ground water Scott Bauer

Environmental Impact of Pesticides in Soil Pesticide Properties That Affect Leaching Solubility: ability to dissolve in water; the more soluble the pesticide, the more likely it will leach Adsorption: the ability of the pesticide to bind tightly and quickly to organic matter in the soil affects leaching; the greater the ability to bind to organic matter, the less likely pesticides will leach Persistence: how long the pesticide remains in the soil; pesticides degraded primarily by sunlight, soil microbes and chemicals in the soil; the more persistent a pesticide, the more likely it will leach into ground water

Environmental Impact of Pesticides in Soil Effects of Pesticide Application on Leaching Rate of application: the higher the rate (amount) of pesticide applied, the greater the chance the pesticides will leach Application method: pesticides applied to growing plants can be absorbed by the plants or broken down by sunlight before reaching soil; soil incorporated pesticides are not exposed to sunlight and have greatest chance of leaching into ground water

Environmental Impact of Pesticides in Soil Effects of Geography & Weather on Leaching Geography: depth from soil surface to ground water (closer ground water is to soil surface, the more pesticide leaches into ground water) Weather: pesticides break down faster in warm, moist soil; therefore, less likely to leach Gene Alexander

Environmental Impact of Pesticides in Ground Water Ground water is water located beneath the earth’s surface, usually in rock or soil Ground water is the primary source of drinking water for 50% of population, 95% of rural residents in the United States Ron Nichols

Environmental Impact of Pesticides in Ground Water At least 143 pesticides and 21 of their transformation products have been found in ground water, from every major chemical class Pesticides commonly found at low levels in agricultural areas (seldom exceed water- quality standards) Pesticides also found in non-agricultural setting such as golf courses and residential areas Ken Hammond

Environmental Impact of Pesticides in Ground Water Pesticides most frequently detected in ground water: Triazine (atrazine) and acetanilide (alachlor and metolachlor) herbicides: used extensively on corn and soybeans in Midwest Carbamate insecticide aldicarb (Temik): ground water contamination problems, sampled for extensively Bill Tarpenning

Environmental Impact of Pesticides in Ground Water Factors strongly associated with pesticide contamination of of ground water are: High pesticide usage in the area High recharge of ground water by precipitation or irrigation High soil permeability Well contamination is greatest in shallow, inadequately sealed wells Tim McCabe

Environmental Impact of Pesticides in Surface Waters Surface waters include streams, rivers, lakes, reservoirs and oceans Streams and reservoirs supply approximately 50% of the drinking water in United States Ken Hammond

Environmental Impact of Pesticides in Surface Waters Pesticides enter surface waters through run-off, wastewater discharges, atmospheric deposition (dry and precipitation), spills and ground water Pesticide concentrations in surface waters follow the seasonal patterns of pesticide application and run-off U. S Geological Survey

Environmental Impact of Pesticides in Surface Waters Low levels of pesticides are widespread in surface waters in the United States Herbicides are detected more frequently than insecticides, due to their greater use Some pesticides exceed water-quality standards during certain seasons, but the annual average concentrations seldom exceed standards Doug Wilson

Environmental Impact of Pesticides in Surface Waters Pesticides most frequently detected in surface waters: Triazine (atrazine) and acetanilide (alachlor and metolachlor) and 2,4-D herbicides: widely used in agriculture Carbofuran and diazinon were the most frequently detected insecticides in current use Bill Tarpenning

Environmental Impact of Pesticides on Plants Pesticides can move from the intended target and damage nearby plants, including crops, forests and ornamental plants Phytotoxicity: plant injury resulting from contact with pesticides and/or inert ingredients in pesticide formulations Scott Bauer Bruce Fritz

Environmental Impact of Pesticides on Wildlife Acute Poisoning: short exposures to some pesticides may kill or sicken wildlife Fish kills caused by pesticide residues carried into waterways by run-off, drift, etc. (e.g., fish kills in Mississippi River resulting from Guthion use in Louisiana) Bird kills caused by birds consuming pesticide-treated vegetation/insects, pesticide granules, bait or treated seed (e.g., birds poisoned by eating granular carbofuran) Ken Hammond

Environmental Impact of Pesticides on Wildlife Chronic Poisoning: exposure to non-lethal levels of pesticides over extended periods can cause reproductive effects, etc. Populations of bald eagles and other birds of prey were reduced by the widespread use of organochlorine insecticides (DDT) in 1950s and 1960s These compounds and metabolites caused reproductive effects in birds Reduction in use of organochlorine insecticides in the 1970s and early 1980s resulted in greatly improved reproduction and increasing bird populations Tim McCabe

Environmental Impact of Pesticides on Wildlife Secondary Poisoning: occurs when animals consume prey that contain pesticide residues and concentrate the pesticide in their bodies (i.e., bioaccumulation) resulting in their poisoning Predators become sick after feeding on dead or dying animals poisoned by pesticides Pesticide residues move up the food chain (plants eaten by plant feeding animals which in turn are eaten by predators) USDA Photograph

Environmental Impact of Pesticides on Wildlife Indirect Effects: adverse effects caused by the modification or elimination of wildlife habitat or food supply Herbicides can reduce food, cover and nesting sites for wildlife Insecticides can reduce insects that serve as food supply for other animals Plant pollination can be effected by reductions in populations of bees and other plant pollinators Ken Hammond

Endangered and Threatened Species of Plants and Animals Endangered species: “any species which is in danger of extinction throughout all or a significant portion of its range” Threatened species: “any species which is likely to become an endangered species within the foreseeable future” Endangered / threatened species of plants and animals protected by the U. S. EPA under the federal Endangered Species Act Tim McCabe

Harmful Effects of Pesticides on Surfaces Pesticides can leave a visible deposit on surfaces (i.e., clothes, carpets, walls, etc.) Pesticides can corrode metal surfaces (i.e., paint on automobiles) Pesticides can short-circuit electrical equipment N. C. Pesticide Applicator Training Program

References Applying Pesticides Correctly: A Guide for Private and Commercial Applicators. Unit 4: Pesticides in the Environment. pp. 39-48. Applying Pesticides Correctly: A Guide for Private and Commercial Applicators. Unit 5: Special Environmental Concerns. pp. 49-59. McLaughlin, R. A., J. B. Weber, and R. L. Warren. 1994. Protecting Groundwater in North Carolina: A Pesticide and Soil Ranking System. AG-439-31. N. C. Cooperative Extension Service, Raleigh. 6 pp. (http://ces.soil.ncsu.edu/soilscience/publications/Soilfacts/AG-439-31/) U. S. Geologic Survey. 1995. Pesticides in the Atmosphere: Current Understanding of Distribution and Major Influences. Fact Sheet FS-152-95. U. S. Geologic Survey, U. S. Dept. of the Interior. 4 pp. (http://water.wr.usgs.gov/pnsp/atmos/)

References U. S. Geologic Survey. 1995. Pesticides in Ground Water: Current Understanding of Distribution and Major Influences. Fact Sheet FS-244-95. U. S. Geologic Survey, U. S. Dept. of the Interior. 4 pp. (http://water.wr.usgs.gov/pnsp/gw/) U. S. Geologic Survey. 1997. Pesticides in Surface Waters: Current Understanding of Distribution and Major Influences. Fact Sheet FS-039-97. U. S. Geologic Survey, U. S. Dept. of the Interior. 4 pp. (http://water.wr.usgs.gov/pnsp/gw/) Whitford, F., Miller, B., Bennett, R., Jones, M., and Blesoe, L. 1994. Pesticides and Wildlife: An Introduction to Testing, Registration, and Risk Management. Publication PP-30. Purdue University Cooperative Extension Service, West Lafayette, Indiana. pp. 6-7. (http://www.agcom.purdue.edu/AgCom/Pubs/PPP/PPP-30.html)