Environmental impact of pesticides
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The environmental effects of pesticides describe the broad series of consequences of using pesticides. The unintended consequences of pesticides is one of the main drivers of the negative impact of modern industrial agriculture on the environment. Pesticides, because they are toxic chemicals meant to kill
pest species A pest is any animal or plant harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environ ...
, can affect non-target
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
, such as
plants Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclude ...
, animals and humans. Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, because they are sprayed or spread across entire agricultural fields. Other agrochemicals, such as
fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
s, can also have negative effects on the environment. The negative effects of pesticides are not just in the area of application. Runoff and
pesticide drift Pesticide drift refers to the unintentional diffusion of pesticides and the potential negative effects of pesticide application, including off-target contamination due to spray drift as well as runoff from plants or soil. This can lead to damag ...
can carry pesticides into distant aquatic environments or other fields, grazing areas, human settlements and undeveloped areas. Other problems emerge from poor production, transport, storage and disposal practices.Tashkent (1998)
Part 75. Conditions and provisions for developing a national strategy for biodiversity conservation
. Biodiversity Conservation National Strategy and Action Plan of Republic of Uzbekistan. Prepared by the National Biodiversity Strategy Project Steering Committee with the Financial Assistance of The Global Environmental Facility (GEF) and Technical Assistance of United Nations Development Programme (UNDP). Retrieved on 17 September 2007.
Over time, repeat application of pesticides increases pest resistance, while its effects on other species can facilitate the pest's resurgence. Alternatives to heavy use of pesticides, such as integrated pest management, and
sustainable agriculture Sustainable agriculture is farming in sustainable ways meeting society's present food and textile needs, without compromising the ability for current or future generations to meet their needs. It can be based on an understanding of ecosystem ser ...
techniques such as polyculture mitigate these consequences, without the harmful toxic chemical application. Environmental modelling indicates that globally over 60% of global agricultural land (~24.5 million km²) is "at risk of pesticide pollution by more than one active ingredient", and that over 30% is at "high risk" of which a third are in high-biodiversity regions. Each pesticide or pesticide class comes with a specific set of environmental concerns. Such undesirable effects have led many pesticides to be banned, while regulations have limited and/or reduced the use of others. The global spread of pesticide use, including the use of older/obsolete pesticides that have been banned in some jurisdictions, has increased overall.


History

After the end of
World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, the United States shifted its industries from the wartime production of chemicals to synthetic agriculturally used pesticide creation, using pyrethrum, rotenone, nicotine, sabadilla, and quassin as precursors to the expansive usage of pesticides in place today. Synthetic pesticides proved cheap and effective in killing insects, but garnered criticism from NGOs concerned about their effect on human health. In the years directly following
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
rose the creation and use of
Aldrin Aldrin is an organochlorine insecticide that was widely used until the 1990s, when it was banned in most countries. Aldrin is a member of the so-called "classic organochlorines" (COC) group of pesticides. COCs enjoyed a very sharp rise in popular ...
(now banned in most countries), " dichlorodiphenyl trichloroethane (DDT) in 1939, Dieldrin, β- Benzene Hexachloride (BHC), 2,4- Dichlorophenoxyacetic acid (2,4-D),
Chlordane Chlordane, or chlordan, is an organochlorine compound that was used as a pesticide. It is a white solid. In the United States, chlordane was used for termite-treatment of approximately 30 million homes until it was banned in 1988. Chlordane was ...
and
Endrin Endrin is an organochloride with the chemical formula C12H8Cl6O that was first produced in 1950 by Shell and Velsicol Chemical Corporation. It was primarily used as an insecticide, as well as a rodenticide and piscicide. It is a colourless, odo ...
". While concern for ecotoxicology began with acute poisoning events in the late 19th century; public concern over the undesirable environmental effects of chemicals arose in the early 1960s with the publication of
Rachel Carson Rachel Louise Carson (May 27, 1907 – April 14, 1964) was an American marine biologist, writer, and conservationist whose influential book '' Silent Spring'' (1962) and other writings are credited with advancing the global environmental ...
′s book, ''
Silent Spring ''Silent Spring'' is an environmental science book by Rachel Carson. Published on September 27, 1962, the book documented the environmental harm caused by the indiscriminate use of pesticides. Carson accused the chemical industry of spreading d ...
''. Shortly thereafter, DDT, originally used to combat
malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...
, and its metabolites were shown to cause population-level effects in raptorial birds. Initial studies in industrialized countries focused on acute mortality effects mostly involving birds or fish.


Modern pesticide usage

However, true data on pesticide usage remain scattered and/or not publicly available, especially worldwide (3). Some scholars argue the common practice of incident registration is inadequate for understanding the entirety of effects. Today, over 3.5 billion kilograms of synthetic pesticides are used for the world's agriculture in an over $45 billion industry. Current lead agrichemical producers include Syngenta (ChemChina), Bayer Crop Science,
BASF BASF SE () is a German multinational chemical company and the largest chemical producer in the world. Its headquarters is located in Ludwigshafen, Germany. The BASF Group comprises subsidiaries and joint ventures in more than 80 countries ...
,
Dow AgroSciences Dow AgroSciences LLC was a wholly owned subsidiary of the Dow Chemical Company specializing in not only agricultural chemicals such as pesticides, but also seeds and biotechnology solutions. The company was based in Indianapolis, Indian ...
, FMC, ADAMA, Nufarm,
Corteva Corteva, Inc. (also known as Corteva Agriscience) is a major American agricultural chemical and seed company that was the agricultural unit of DowDuPont prior to being spun off as an independent public company. DowDuPont announced the Corteva na ...
, Sumitomo Chemical, UPL, and Huapont Life Sciences. Bayer CropScience and its acquisition of Monsanto led it to record profits in 2019 of over $10 billion in sales, which herbicide shares growing by 22%, followed closely by Syngenta. In 2016, the United States consumed 322 million pounds ONVERTof pesticides banned in the EU, 26 million pounds ONVERTof pesticides banned in Brazil and 40 million pounds of pesticides banned in China, with most of banned pesticides banned staying constant or increasing in the United States over the past 25 years according to studies.


Scholarly research

Since 1990, research interest has shifted from documenting incidents and quantifying chemical exposure to studies aimed at linking laboratory,
mesocosm thumb , Diagram of a small form closed system mesocosm. A mesocosm (''meso-'' or 'medium' and ''-cosm'' 'world') is any outdoor experimental system that examines the natural environment under controlled conditions. In this way mesocosm studie ...
and field experiments. The proportion of effect-related publications has increased. Animal studies mostly focus on fish, insects, birds, amphibians and arachnids. Since 1993, the United States and the
European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been de ...
have updated pesticide risk assessments, ending the use of acutely toxic organophosphate and carbamate insecticides. Newer pesticides aim at efficiency in target and minimum side effects in nontarget organisms. The phylogenetic proximity of beneficial and pest species complicates the project. One of the major challenges is to link the results from cellular studies through many levels of increasing complexity to ecosystems. The concept (borrowed from nuclear physics) of a half-life has been used for pesticides in plants, and certain authors maintain that pesticide risk and impact assessment models rely on and are sensitive to information describing dissipation from plants. Half-life for pesticides is explained in two NPIC fact sheets. Known degradation pathways are through: photolysis, chemical dissociation, sorption, bioaccumulation and plant or animal
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run c ...
. A
USDA The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...
fact sheet published in 1994 lists the soil adsorption coefficient and
soil Soil, also commonly referred to as earth or dirt Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Debri ...
half-life for then-commonly used pesticides.


Specific pesticide effects


Persistent organic pollutants

Persistent organic pollutant Persistent organic pollutants (POPs), sometimes known as "forever chemicals", are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. They are toxic chemicals that adversel ...
s (POPs) are compounds that resist degradation and thus remain in the environment for years. Some pesticides, including
aldrin Aldrin is an organochlorine insecticide that was widely used until the 1990s, when it was banned in most countries. Aldrin is a member of the so-called "classic organochlorines" (COC) group of pesticides. COCs enjoyed a very sharp rise in popular ...
,
chlordane Chlordane, or chlordan, is an organochlorine compound that was used as a pesticide. It is a white solid. In the United States, chlordane was used for termite-treatment of approximately 30 million homes until it was banned in 1988. Chlordane was ...
,
DDT Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...
, dieldrin,
endrin Endrin is an organochloride with the chemical formula C12H8Cl6O that was first produced in 1950 by Shell and Velsicol Chemical Corporation. It was primarily used as an insecticide, as well as a rodenticide and piscicide. It is a colourless, odo ...
,
heptachlor Heptachlor is an organochlorine compound that was used as an insecticide. Usually sold as a white or tan powder, heptachlor is one of the cyclodiene insecticides. In 1962, Rachel Carson's ''Silent Spring'' questioned the safety of heptachlor and ...
, hexachlorobenzene,
mirex Mirex was an organochloride that was commercialized as an insecticide and later banned because of its impact on the environment. This white crystalline odorless solid is a derivative of cyclopentadiene. It was popularized to control fire ants b ...
and
toxaphene Toxaphene was an insecticide used primarily for cotton in the southern United States during the late 1960s and the 1970s. Toxaphene is a mixture of over 670 different chemicals and is produced by reacting chlorine gas with camphene. It can be mo ...
, are considered POPs. Some POPs have the ability to volatilize and travel great distances through the atmosphere to become deposited in remote regions. Such chemicals may have the ability to
bioaccumulate Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...
and
biomagnify Biomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain. This increase can occur as a ...
and can
biomagnify Biomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain. This increase can occur as a ...
(i.e. become more concentrated) up to 70,000 times their original concentrations.Ritter L, Solomon KR, and Forget J, Stemeroff M, and O'Leary C
Persistent organic pollutants: An Assessment Report on: DDT, Aldrin, Dieldrin, Endrin, Chlordane, Heptachlor, Hexachlorobenzene, Mirex, Toxaphene, Polychlorinated Biphenyls, Dioxins and Furans
. Prepared for The International Programme on Chemical Safety (IPCS), within the framework of the Inter-Organization Programme for the Sound Management of Chemicals (IOMC). Retrieved on 16 September 2007.
POPs can affect non-target organisms in the environment and increase risk to humans by disruption in the endocrine, reproductive, and
respiratory system The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies ...
s.


Environmental effects


Air

Pesticides can contribute to air pollution.
Pesticide drift Pesticide drift refers to the unintentional diffusion of pesticides and the potential negative effects of pesticide application, including off-target contamination due to spray drift as well as runoff from plants or soil. This can lead to damag ...
occurs when pesticides suspended in the air as particles are carried by wind to other areas, potentially contaminating them.Cornell University.
Pesticides in the environment
. Pesticide fact sheets and tutorial, . Pesticide Safety Education Program. Retrieved on 11 October 2007.
Pesticides that are applied to crops can volatilize and may be blown by winds into nearby areas, potentially posing a threat to wildlife. Weather conditions at the time of application as well as temperature and relative humidity change the spread of the pesticide in the air. As wind velocity increases so does the spray drift and exposure. Low relative humidity and high temperature result in more spray evaporating. The amount of inhalable pesticides in the outdoor environment is therefore often dependent on the season. Also, droplets of sprayed pesticides or particles from pesticides applied as dusts may travel on the wind to other areas, or pesticides may adhere to particles that blow in the wind, such as dust particles. Ground spraying produces less pesticide drift than aerial spraying does. Farmers can employ a buffer zone around their crop, consisting of empty land or non-crop plants such as
Evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...
trees to serve as windbreaks and absorb the pesticides, preventing drift into other areas.''Science Daily'' (19 November 1999)
Evergreens help block spread of pesticide from crop fields
Sciencedaily.com. Retrieved on 19 September 2007.
Such windbreaks are legally required in the
Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...
. Pesticides that are sprayed on to fields and used to fumigate soil can give off chemicals called
volatile organic compound Volatile organic compounds (VOCs) are organic compounds that have a high vapour pressure at room temperature. High vapor pressure correlates with a low boiling point, which relates to the number of the sample's molecules in the surrounding air, a ...
s, which can react with other chemicals and form a pollutant called
ground level ozone Ground-level ozone (O3), also known as surface-level ozone and tropospheric ozone, is a trace gas in the troposphere (the lowest level of the Earth's atmosphere), with an average concentration of 20–30 parts per billion by volume (ppbv), with c ...
. Pesticide use accounts for about 6 percent of total ground level ozone levels.


Water

In the United States, pesticides were found to pollute every stream and over 90% of wells sampled in a study by the
US Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and ...
. Pesticide residues have also been found in rain and groundwater.Kellogg RL, Nehring R, Grube A, Goss DW, and Plotkin S (February 2000)
Environmental indicators of pesticide leaching and runoff from farm fields
. United States Department of Agriculture Natural Resources Conservation Service. Retrieved on 3 October 2007.
Studies by the UK government showed that pesticide concentrations exceeded those allowable for drinking water in some samples of river water and groundwater. Pesticide impacts on aquatic systems are often studied using a
hydrology transport model An hydrological transport model is a mathematical model used to simulate the flow of rivers, streams, groundwater movement or drainage front displacement, and calculate water quality parameters. These models generally came into use in the 1960s a ...
to study movement and fate of chemicals in rivers and streams. As early as the 1970s quantitative analysis of pesticide runoff was conducted to predict amounts of pesticide that would reach surface waters. There are four major routes through which pesticides reach the water: it may drift outside of the intended area when it is sprayed, it may percolate, or leach through the soil, it may be carried to the water as runoff, or it may be spilled, for example accidentally or through neglect. They may also be carried to water by eroding soil. Factors that affect a pesticide's ability to contaminate water include its water
solubility In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solub ...
, the distance from an application site to a body of water, weather, soil type, presence of a growing crop, and the method used to apply the chemical.Pedersen, TL (June 1997)
Pesticide residues in drinking water
extoxnet.orst.edu. Retrieved on 15 September 2007.


Water-focused regulations

In United States regulation , maximum limits of allowable conce ntrations for individual pesticides in
drinking water Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...
are set by the Environmental Protection Agency (EPA) for public water systems. (There are no federal standards for private wells.) Ambient water quality standards for pesticide concentrations in water bodies are principally developed by state environmental agencies, with EPA oversight. These standards may be issued for individual water bodies, or may apply statewide. The United Kingdom sets Environmental Quality Standards (EQS), or maximum allowable concentrations of some pesticides in bodies of water above which toxicity may occur.Bingham, S (2007)
Pesticides exceeding environmental quality standards (EQS)
. The Environment Agency, UK. Retrieved on 12 October 2007.
The European Union regulates maximum concentrations of pesticides in water.


Soil

The extensive use of pesticides in agricultural production can degrade and damage the community of microorganisms living in the soil, particularly when these chemicals are overused or misused as chemical compounds build up in the soil. The full impact of pesticides on soil microorganisms is still not entirely understood; many studies have found deleterious effects of pesticides on soil microorganisms and biochemical processes, while others have found that the residue of some pesticides can be degraded and assimilated by microorganisms. The effect of pesticides on soil microorganisms is impacted by the persistence, concentration, and toxicity of the applied pesticide, in addition to various environmental factors. This complex interaction of factors makes it difficult to draw definitive conclusions about the interaction of pesticides with the soil ecosystem. In general, long-term pesticide application can disturb the biochemical processes of nutrient cycling. Many of the chemicals used in pesticides are persistent soil contaminants, whose impact may endure for decades and adversely affect
soil conservation Soil conservation is the prevention of loss of the topmost layer of the soil from erosion or prevention of reduced fertility caused by over usage, acidification, salinization or other chemical soil contamination. Slash-and-burn and other uns ...
. The use of pesticides decreases the general biodiversity in the soil. Not using the chemicals results in higher
soil quality Soil quality refers to the condition of soil based on its capacity to perform ecosystem services that meet the needs of human and non-human life.Tóth, G., Stolbovoy, V. and Montanarella, 2007. Soil Quality and Sustainability Evaluation - An integr ...
, with the additional effect that more organic matter in the soil allows for higher water retention. This helps increase yields for farms in drought years, when organic farms have had yields 20-40% higher than their conventional counterparts. A smaller content of organic matter in the soil increases the amount of pesticide that will leave the area of application, because organic matter binds to and helps break down pesticides. Degradation and sorption are both factors which influence the persistence of pesticides in soil. Depending on the chemical nature of the pesticide, such processes control directly the transportation from soil to water, and in turn to air and our food. Breaking down organic substances, degradation, involves interactions among microorganisms in the soil. Sorption affects bioaccumulation of pesticides which are dependent on organic matter in the soil. Weak organic acids have been shown to be weakly sorbed by soil, because of pH and mostly acidic structure. Sorbed chemicals have been shown to be less accessible to microorganisms. Aging mechanisms are poorly understood but as residence times in soil increase, pesticide residues become more resistant to degradation and extraction as they lose biological activity.


Impact on living beings

The impact on living beings also affects the non-living environment and humans indirectly.


Plants

Nitrogen fixation, which is required for the growth of
higher plant Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They a ...
s, is hindered by pesticides in soil.Rockets, Rusty (8 June 2007)
Down On The Farm? Yields, Nutrients And Soil Quality
Scienceagogo.com. Retrieved on 15 September 2007.
The insecticides
DDT Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...
, methyl parathion, and especially pentachlorophenol have been shown to interfere with legume- rhizobium chemical signaling. Reduction of this symbiotic chemical signaling results in reduced nitrogen fixation and thus reduced crop yields. Root nodule formation in these plants saves the world economy $10 billion in synthetic nitrogen
fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
every year. On the other side, pesticides have some direct harmful effect on plant including poor root hair development, shoot yellowing and reduced plant growth.


Pollinators

Pesticides can kill bees and are strongly implicated in pollinator decline, the loss of species that pollinate plants, including through the mechanism of
Colony Collapse Disorder Colony collapse disorder (CCD) is an abnormal phenomenon that occurs when the majority of worker bees in a honey bee colony disappear, leaving behind a queen, plenty of food, and a few nurse bees to care for the remaining immature bees. While s ...
, in which worker bees from a
beehive A beehive is an enclosed structure in which some honey bee species of the subgenus '' Apis'' live and raise their young. Though the word ''beehive'' is commonly used to describe the nest of any bee colony, scientific and professional literature ...
or
western honey bee The western honey bee or European honey bee (''Apis mellifera'') is the most common of the 7–12 species of honey bees worldwide. The genus name ''Apis'' is Latin for "bee", and ''mellifera'' is the Latin for "honey-bearing" or "honey carrying" ...
colony abruptly disappear. Application of pesticides to crops that are in bloom can kill
honeybee A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosm ...
s, which act as pollinators. The
USDA The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of com ...
and
USFWS The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...
estimate that US farmers lose at least $200 million a year from reduced crop pollination because pesticides applied to fields eliminate about a fifth of honeybee colonies in the US and harm an additional 15%.


Animals

Many kinds of animals are harmed by pesticides, leading many countries to regulate pesticide usage through Biodiversity Action Plans. Animals including humans may be poisoned by pesticide residues that remain on food, for example when wild animals enter sprayed fields or nearby areas shortly after spraying. Pesticides can eliminate some animals' essential food sources, causing the animals to relocate, change their diet or starve. Residues can travel up the
food chain A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), de ...
; for example, birds can be harmed when they eat insects and worms that have consumed pesticides. Earthworms digest organic matter and increase nutrient content in the top layer of soil. They protect human health by ingesting decomposing litter and serving as bioindicators of soil activity. Pesticides have had harmful effects on growth and reproduction on earthworms. Some pesticides can
bioaccumulate Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...
, or build up to toxic levels in the bodies of organisms that consume them over time, a phenomenon that impacts species high on the food chain especially hard.


Birds

The US
Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...
estimates that 72 million birds are killed by pesticides in the United States each year. Bald eagles are common examples of nontarget organisms that are impacted by pesticide use.
Rachel Carson Rachel Louise Carson (May 27, 1907 – April 14, 1964) was an American marine biologist, writer, and conservationist whose influential book '' Silent Spring'' (1962) and other writings are credited with advancing the global environmental ...
's book ''
Silent Spring ''Silent Spring'' is an environmental science book by Rachel Carson. Published on September 27, 1962, the book documented the environmental harm caused by the indiscriminate use of pesticides. Carson accused the chemical industry of spreading d ...
'' uncovered the effects of bioaccumulation of the pesticide
DDT Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...
in 1962. Farmland birds are declining more rapidly than birds of any other biome in North America, a decline that is correlated with intensification and expansion of pesticide usage. In the farmland of the United Kingdom, populations of ten different bird species declined by 10 million breeding individuals between 1979 and 1999, allegedly from loss of plant and invertebrate species on which the birds feed. Throughout Europe, 116 species of birds were threatened as of 1999. Reductions in bird populations have been found to be associated with times and areas in which pesticides are used.Kerbs JR, Wilson JD, Bradbury RB, and Siriwardena GM (12 August 1999)
The second silent spring
. Commentary in ''Nature'', Volume 400, Pages 611–612.
DDE-induced egg shell thinning has especially affected European and North American bird populations. From 1990 to 2014 the number of common farmland birds has declined in the
European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been de ...
as a whole and in France,
Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...
and Sweden; in Germany, which relies more on organic farming and less on pesticides the decline has been slower; in Switzerland, which does not rely much on intensive agriculture, after a decline in the early 2000s the level has returned to the one of 1990. In another example, some types of fungicides used in peanut farming are only slightly toxic to birds and mammals, but may kill earthworms, which can in turn reduce populations of the birds and mammals that feed on them. Some pesticides come in granular form. Wildlife may eat the granules, mistaking them for grains of food. A few granules of a pesticide may be enough to kill a small bird.Palmer, WE, Bromley, PT, and Brandenburg, RL
Wildlife & pesticides – Peanuts
North Carolina Cooperative Extension Service. Retrieved on 11 October 2007.
Herbicides may endanger bird populations by reducing their habitat. Furthermore, destruction of native habitat and conversion into other land-use types (e.g. agricultural, residential) contributes to the decline of these birds.


Aquatic life

Fish and other aquatic biota may be harmed by pesticide-contaminated water.Helfrich, LA, Weigmann, DL, Hipkins, P, and Stinson, ER (June 1996)

. Virginia Cooperative Extension. Retrieved on 14 October 2007.
Pesticide surface runoff into rivers and streams can be highly lethal to aquatic life, sometimes killing all the fish in a particular stream.Toughill K (1999)
The summer the rivers died: Toxic runoff from potato farms is poisoning P.E.I.
Originally published in ''Toronto Star Atlantic Canada Bureau''. Retrieved on 17 September 2007.
Application of herbicides to bodies of water can cause fish kills when the dead plants decay and consume the water's oxygen, suffocating the fish. Herbicides such as copper sulfate that are applied to water to kill plants are toxic to fish and other water animals at concentrations similar to those used to kill the plants. Repeated exposure to sublethal doses of some pesticides can cause physiological and behavioral changes that reduce fish populations, such as abandonment of nests and broods, decreased immunity to disease and decreased predator avoidance. Application of herbicides to bodies of water can kill plants on which fish depend for their habitat. Pesticides can accumulate in bodies of water to levels that kill off zooplankton, the main source of food for young fish. Pesticides can also kill off insects on which some fish feed, causing the fish to travel farther in search of food and exposing them to greater risk from predators. The faster a given pesticide breaks down in the environment, the less threat it poses to aquatic life. Insecticides are typically more toxic to aquatic life than herbicides and fungicides.


Amphibians

In the past several decades, amphibian populations have declined across the world, for unexplained reasons which are thought to be varied but of which pesticides may be a part.Cone M (6 December 2000)
A wind-borne threat to Sierra frogs: A study finds that pesticides used on farms in the San Joaquin Valley damage the nervous systems of amphibians in Yosemite and elsewhere
. ''L.A. Times'' Retrieved on 17 September 2007.
Pesticide mixtures appear to have a cumulative toxic effect on frogs. Tadpoles from ponds containing multiple pesticides take longer to
metamorphose Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some insec ...
and are smaller when they do, decreasing their ability to catch prey and avoid predators.''Science Daily'' (3 February 2006)
Pesticide combinations imperil frogs, probably contribute to amphibian decline
Sciencedaily.com. Retrieved on 16 October 2007.
Exposing tadpoles to the
organochloride An organochloride, organochlorine compound, chlorocarbon, or chlorinated hydrocarbon is an organic compound containing at least one covalently bonded atom of chlorine. The chloroalkane class (alkanes with one or more hydrogens substituted by chlo ...
endosulfan at levels likely to be found in habitats near fields sprayed with the chemical kills the tadpoles and causes behavioral and growth abnormalities. The herbicide atrazine can turn male frogs into hermaphrodites, decreasing their ability to reproduce. Both reproductive and nonreproductive effects in aquatic reptiles and amphibians have been reported. Crocodiles, many turtle species and some lizards lack sex-distinct chromosomes until after fertilization during
organogenesis Organogenesis is the phase of embryonic development that starts at the end of gastrulation and continues until birth. During organogenesis, the three germ layers formed from gastrulation (the ectoderm, endoderm, and mesoderm) form the internal org ...
, depending on temperature. Embryonic exposure in turtles to various
PCBs Polychlorinated biphenyls (PCBs) are highly carcinogenic chemical compounds, formerly used in industrial and consumer products, whose production was banned in the United States by the Toxic Substances Control Act in 1979 and internationally by t ...
causes a sex reversal. Across the United States and Canada disorders such as decreased hatching success, feminization, skin lesions, and other developmental abnormalities have been reported.


Humans

Pesticides can enter the body through inhalation of aerosols, dust and
vapor In physics, a vapor (American English) or vapour (British English and Canadian English; see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature,R. H. Petrucci, W. S. Harwood, and F. G. Her ...
that contain pesticides; through oral exposure by consuming food/water; and through skin exposure by direct contact.California Department of Pesticide Regulation (2008), "What are the Potential Health Effects of Pesticides?" Community Guide to Recognizing and Reporting Pesticide Problems. Sacramento, CA. Pages 27–29. Pesticides secrete into soils and groundwater which can end up in drinking water, and pesticide spray can drift and pollute the air. The
effects of pesticides on human health Health effects of pesticides may be acute or delayed in those who are exposed. Acute effects can include pesticide poisoning, which may be a medical emergency. Strong evidence exists for other, long-term negative health outcomes from pesticide exp ...
depend on the toxicity of the chemical and the length and magnitude of exposure. Farm workers and their families experience the greatest exposure to agricultural pesticides through direct contact. Every human contains pesticides in their fat cells. Children are more susceptible and sensitive to pesticides, because they are still developing and have a weaker immune system than adults. Children may be more exposed due to their closer proximity to the ground and tendency to put unfamiliar objects in their mouth. Hand to mouth contact depends on the child's age, much like lead exposure. Children under the age of six months are more apt to experience exposure from breast milk and inhalation of small particles. Pesticides tracked into the home from family members increase the risk of exposure. Toxic residue in food may contribute to a child's exposure. Epidemiological studies have reported adverse effects of certain pesticides at current levels of exposure on children's cognitive development. The chemicals can bioaccumulate in the body over time. Exposure effects can range from mild skin irritation to birth defects, tumors, genetic changes, blood and nerve disorders,
endocrine disruption Endocrine disruptors, sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds are chemicals that can interfere with endocrine (or hormonal) systems. These disruptions can cause ca ...
, coma or death. Developmental effects have been associated with pesticides. Recent increases in childhood cancers in throughout North America, such as
leukemia Leukemia ( also spelled leukaemia and pronounced ) is a group of blood cancers that usually begin in the bone marrow and result in high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or ...
, may be a result of somatic cell mutations. Insecticides targeted to disrupt insects can have harmful effects on mammalian nervous systems. Both chronic and acute alterations have been observed in exposes. DDT and its breakdown product DDE disturb estrogenic activity and possibly lead to breast cancer. Fetal DDT exposure reduces male
penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males d ...
size in animals and can produce undescended
testicle A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoste ...
s. Pesticide can affect fetuses in early stages of development, in utero and even if a parent was exposed before conception. Reproductive disruption has the potential to occur by chemical reactivity and through structural changes.


Pest resistance


Pest rebound and secondary pest outbreaks

Non-target organisms can also be impacted by pesticides. In some cases, a pest insect that is controlled by a beneficial
predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
or parasite can flourish should an insecticide application kill both pest and beneficial populations. A study comparing biological pest control and pyrethroid insecticide for diamondback moths, a major cabbage family insect pest, showed that the pest population rebounded due to loss of insect
predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
s, whereas the biocontrol did not show the same effect. Likewise, pesticides sprayed to control
mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
es may temporarily depress mosquito populations, they may result in a larger population in the long run by damaging natural controls. This phenomenon, wherein the population of a pest species rebounds to equal or greater numbers than it had before pesticide use, is called pest resurgence and can be linked to elimination of its predators and other natural enemies. Loss of predator species can also lead to a related phenomenon called secondary pest outbreaks, an increase in problems from species that were not originally a problem due to loss of their predators or parasites. An estimated third of the 300 most damaging insects in the US were originally secondary pests and only became a major problem after the use of pesticides. In both pest resurgence and secondary outbreaks, their natural enemies were more susceptible to the pesticides than the pests themselves, in some cases causing the pest population to be higher than it was before the use of pesticide.


Alternatives

Many alternatives are available to reduce the effects pesticides have on the environment. Alternatives to pesticides include manual removal, applying heat, covering weeds with plastic, placing traps and lures, removing pest breeding sites, maintaining healthy soils that breed healthy, more resistant plants, cropping native species that are naturally more resistant to native pests and supporting biocontrol agents such as birds and other pest predators. In the United States, conventional pesticide use peaked in 1979, and by 2007, had been reduced by 25 percent from the 1979 peak level, while US agricultural output increased by 43 percent over the same period. Biological controls such as resistant plant varieties and the use of
pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s, have been successful and at times permanently resolve a pest problem.Lewis, W. J., J. C. van Lenteren, Sharad C. Phatak, and J. H. Tumlinson, III. "A total system approach to sustainable pest management." The National Academy of Sciences 13 August 1997. Web of Science. Integrated Pest Management (IPM) employs chemical use only when other alternatives are ineffective. IPM causes less harm to humans and the environment. The focus is broader than on a specific pest, considering a range of pest control alternatives.
Biotechnology Biotechnology is the integration of natural sciences and engineering sciences in order to achieve the application of organisms, cells, parts thereof and molecular analogues for products and services. The term ''biotechnology'' was first used ...
can also be an innovative way to control pests. Strains can be
genetically modified Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including ...
(GM) to increase their resistance to pests. Biopesticides such as canola oil and baking soda that contain curtain active ingredients from natural substances are an environmentally friendly alternative for toxic pesticides. There are three categories of biopesticides; microbial pesticides, plant-incorporated protectants (PIPs), and biochemical biopesticides. The alternatives to pesticides include a range of genetic material introduction to plants that target a particular pest, and active ingredients that control the mating and reproduction of certain pests or kill target pests. Biopesticides are affective in small quantities and degrade quickly making them an eco-friendly alternative to pesticides. They are often used in Integrated Pest Management (IPM) as well and has been an important component to the UK IPM strategy for its crop protection.


Waste and disposal

In the United States, the Environmental Protection Agency (EPA) suggests proper use of pesticides and disposal that follows federal or individual state guidance for farmers or commercial users. Commercial users of pesticides are told to follow the disposal instructions on the labels of the pesticides while using necessary safety measures for the disposal of hazardous waste. They are also advised to call for assistance by their local agencies in the disposal of unwanted or unused pesticides. Still are there environmental problems that emerge from runoff and other negative effects of pesticides. Runoff of pesticides into to wastewater and pesticide drift into other ecosystems has led to research in the removal and remediation of pesticides in the environment. Research has been done on different methods to treat pesticide pollution including the use of activated carbon absorption and advanced oxidation processes. Different methods of pesticide removal require different costs and can carry different removal outcomes. Some methods require low cost techniques but many result in byproducts that require an extra cost for removal or unwarranted environmental impacts. There is an ongoing research focused on pesticide removal, a 2022 study for example demonstrated excellent removal efficiency of 80% for often used pesticide
chlorpyrifos Chlorpyrifos (CPS), also known as Chlorpyrifos ethyl, is an organophosphate pesticide that has been used on crops, animals, and buildings, and in other settings, to kill several pests, including insects and worms. It acts on the nervous systems ...
through usage magnetic plant biobots.


Activated carbon absorption

Due to the properties of activated carbon, different types have been researched as potential treatment for absorbing different pesticide species. Researchers found a use for activated carbon from tangerine seeds in the absorption of pesticides. Researches are utilizing this tangerine seed activated carbon in the removal process of carbamate pesticides that have been linked to an increased risk of cancer and other health risks. Absorption by activated carbon has been found to be a successful and cost-efficient way of removing pesticides.


Advanced oxidation process (AOP)

Advanced oxidation processes have been used to combat against the problem of pesticide residue on fruits and vegetables. AOP and its technologies have been used in the removal efforts of pesticide pollutants in wastewater using different chemical reactions to target different pollutants. Researchers have found this method of pesticide removal using coupled free chlorine/ultrasound to be successful at removing pesticide residue from vegetables.


Activism


Pesticide Action Network

While dubbed economic and ecologically sound practices by suppliers, the effects of agricultural pesticides can include toxicity, bioaccumulation, persistence, and physiological responses in humans and wildlife, and several international NGOs, such as Pesticide Action Network, have risen in response to the economic activities of these larger transnational corporations. Historically, PAN's contributions targeting the Dirty Dozen have resulted in treaties and global environmental law banning
persistent organic pollutant Persistent organic pollutants (POPs), sometimes known as "forever chemicals", are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. They are toxic chemicals that adversel ...
s (POPs), such as endosulfan, and their campaign work on Prior Informed Consent (PIC) for countries in the Global South to know what hazardous and banned chemicals they might be importing have contributed to the culmination of the Rotterdam Convention on Prior Informed Consent, which went into effect in 2004. PAN's work, according to their website, involves "shifting global aid away from pesticides", in addition to community monitoring and serving as a watchdog for the World Bank policy failures. Additionally, Pesticide Action Network members helped co-author the International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD), working to center agroecological knowledge and farming techniques as crucial to the future of agriculture.


See also

* Pesticides in the United States *
Health effects of pesticides Health effects of pesticides may be acute or delayed in those who are exposed. Acute effects can include pesticide poisoning, which may be a medical emergency. Strong evidence exists for other, long-term negative health outcomes from pesticide exp ...


References


External links


National Pesticide Information Center – What happens to pesticides released in the environment?
* Streaming online video about efforts to reduce pesticide use in rice in Bangladesh. Windows Media Playe

RealPlaye


Reptile Amphibian & Pesticide (RAP) Database


– pesticide information profiles. Environmental and health information broken down by type of pesticide {{DEFAULTSORT:Environmental Effects Of Pesticides Environmental effects of pesticides,