Effects Of Pesticides On Amphibians
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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, can affect non-target species, such as plants, animals and humans. Over 98% of sprayed
insecticide Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to b ...
s and 95% of
herbicide Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page fo ...
s reach a destination other than their target species, because they are sprayed or spread across entire agricultural fields. Other
agrochemical An agrochemical or agrichemical, a contraction of ''agricultural chemical'', is a chemical product used in industrial agriculture. Agrichemical refers to biocides ( pesticides including insecticides, herbicides, fungicides and nematicides) an ...
s, such as fertilizers, 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 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 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 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 environme ...
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, 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 rose the creation and use of Aldrin (now banned in most countries), "
dichlorodiphenyl trichloroethane Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless Crystallinity, crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its Environme ...
(DDT) in 1939,
Dieldrin Dieldrin is an organochloride originally produced in 1948 by J. Hyman & Co, Denver, as an insecticide. Dieldrin is closely related to aldrin, which reacts further to form dieldrin. Aldrin is not toxic to insects; it is oxidized in the insect to fo ...
, β- Benzene Hexachloride (BHC), 2,4- Dichlorophenoxyacetic acid (2,4-D), Chlordane and Endrin". 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′s book, '' Silent Spring''. Shortly thereafter, DDT, originally used to combat malaria, 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 Syngenta AG is a provider of agricultural science and technology, in particular seeds and pesticides with its management headquarters in Basel, Switzerland. It is owned by ChemChina, a Chinese state-owned enterprise. Syngenta was founded in 2 ...
(ChemChina),
Bayer Bayer AG (, commonly pronounced ; ) is a German multinational corporation, multinational pharmaceutical and biotechnology company and one of the largest pharmaceutical companies in the world. Headquartered in Leverkusen, Bayer's areas of busi ...
Crop Science, BASF, Dow AgroSciences, FMC, ADAMA, Nufarm, Corteva,
Sumitomo The is one of the largest Japanese ''keiretsu'', or business groups, founded by Masatomo Sumitomo (1585-1652) around 1615 during the early Edo period. History The Sumitomo Group traces its roots to a bookshop in Kyoto founded circa 1615 by Masa ...
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 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 have updated pesticide risk assessments, ending the use of acutely toxic
organophosphate In organic chemistry, organophosphates (also known as phosphate esters, or OPEs) are a class of organophosphorus compounds with the general structure , a central phosphate molecule with alkyl or aromatic substituents. They can be considered a ...
and
carbamate In organic chemistry, a carbamate is a category of organic compounds with the general formula and structure , which are formally derived from carbamic acid (). The term includes organic compounds (e.g., the ester ethyl carbamate), formally o ...
insecticides. Newer pesticides aim at efficiency in target and minimum side effects in nontarget organisms. The
phylogenetic proximity In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
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 Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampric ...
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 Photodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by photons. It is defined as the interaction of one or more photons with one target molecule. ...
,
chemical dissociation Dissociation in chemistry is a general process in which molecules (or ionic compounds such as salts, or complexes) separate or split into other things such as atoms, ions, or radicals, usually in a reversible manner. For instance, when an acid ...
, sorption,
bioaccumulation 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 plant or animal metabolism. A USDA fact sheet published in 1994 lists the soil adsorption coefficient and soil half-life for then-commonly used pesticides.


Specific pesticide effects


Persistent organic pollutants

Persistent organic pollutants (POPs) are compounds that resist degradation and thus remain in the environment for years. Some pesticides, including aldrin, chlordane, DDT,
dieldrin Dieldrin is an organochloride originally produced in 1948 by J. Hyman & Co, Denver, as an insecticide. Dieldrin is closely related to aldrin, which reacts further to form dieldrin. Aldrin is not toxic to insects; it is oxidized in the insect to fo ...
, endrin, heptachlor, hexachlorobenzene, mirex and toxaphene, 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 and biomagnify and can biomagnify (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 The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neu ...
,
reproductive The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are als ...
, and respiratory systems.


Environmental effects


Air

Pesticides can contribute to air pollution. Pesticide drift 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 In chemistry, volatility is a material quality which describes how readily a substance vaporizes. At a given temperature and pressure, a substance with high volatility is more likely to exist as a vapour, while a substance with low volatility is ...
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 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. Pesticides that are sprayed on to fields and used to
fumigate Fumigation is a method of pest control or the removal of harmful micro-organisms by completely filling an area with gaseous pesticides—or fumigants—to suffocate or poison the pests within. It is used to control pests in buildings (s ...
soil can give off chemicals called volatile organic compounds, which can react with other chemicals and form a pollutant called ground level ozone. 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. 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 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, the distance from an application site to a body of water, weather,
soil type A soil type is a taxonomic unit in soil science. All soils that share a certain set of well-defined properties form a distinctive soil type. Soil type is a technical term of soil classification, the science that deals with the systematic categoriz ...
, 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 are set by the
Environmental Protection Agency A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...
(EPA) for
public water system Public water system is a regulatory term used in the United States and Canada, referring to certain utilities and organizations providing drinking water. United States The US Safe Drinking Water Act and derivative legislation define "public water ...
s. (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 A biophysical environment is a life, biotic and Abiotic component, abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environ ...
(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 Soil ecology is the study of the interactions among soil organisms, and between biotic and abiotic aspects of the soil environment. It is particularly concerned with the cycling of nutrients, formation and stabilization of the pore structure, the ...
. In general, long-term pesticide application can disturb the biochemical processes of nutrient cycling. Many of the chemicals used in pesticides are persistent
soil contaminant Soil contamination, soil pollution, or land pollution as a part of land degradation is caused by the presence of xenobiotic (human-made) chemicals or other alteration in the natural soil environment. It is typically caused by industrial activity ...
s, whose impact may endure for decades and adversely affect soil conservation. The use of pesticides decreases the general biodiversity in the soil. Not using the chemicals results in higher soil quality, 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 plants, 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,
methyl parathion Parathion methyl, or methyl parathion, is an organophosphate insecticide, possessing an organothiophosphate group. It is structurally very similar to parathion-ethyl. It is not allowed for sale and import in nearly all countries around the world, ...
, and especially
pentachlorophenol Pentachlorophenol (PCP) is an organochlorine compound used as a pesticide and a disinfectant. First produced in the 1930s, it is marketed under many trade names. It can be found as pure PCP, or as the sodium salt of PCP, the latter of which diss ...
have been shown to interfere with
legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...
- rhizobium chemical signaling. Reduction of this symbiotic chemical signaling results in reduced nitrogen fixation and thus reduced crop yields.
Root nodule Root nodules are found on the roots of plants, primarily legumes, that form a symbiosis with nitrogen-fixing bacteria. Under nitrogen-limiting conditions, capable plants form a symbiotic relationship with a host-specific strain of bacteria known a ...
formation in these plants saves the world economy $10 billion in synthetic nitrogen fertilizer 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, in which worker bees from a beehive or western honey bee colony abruptly disappear. Application of pesticides to crops that are in bloom can kill honeybees, which act as pollinators. The USDA and USFWS 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; 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, 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 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's book '' Silent Spring'' uncovered the effects of
bioaccumulation 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 ...
of the pesticide DDT 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 as a whole and in France, Belgium and Sweden; in Germany, which relies more on organic farming and less on pesticides the decline has been slower; in
Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...
, 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
fungicide Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, ...
s 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 Surface runoff (also known as overland flow) is the flow of water occurring on the ground surface when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when th ...
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 kill The term fish kill, known also as fish die-off, refers to a localized die-off of fish populations which may also be associated with more generalized mortality of aquatic life.University of Florida. Gainesville, FL (2005) ''Plant Management in Fl ...
s 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 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
endosulfan Endosulfan is an off-patent organochlorine insecticide and acaricide that is being phased out globally. It became a highly controversial agrichemical due to its acute toxicity, potential for bioaccumulation, and role as an endocrine disruptor. ...
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
hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...
s, decreasing their ability to reproduce. Both reproductive and nonreproductive effects in
aquatic reptile Aquatic means relating to water; living in or near water or taking place in water; does not include groundwater, as "aquatic" implies an environment where plants and animals live. Aquatic(s) may also refer to: * Aquatic animal, either vertebrate ...
s and amphibians have been reported. Crocodiles, many turtle species and some lizards lack sex-distinct chromosomes until after fertilization during organogenesis, depending on temperature. Embryonic exposure in turtles to various PCBs 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
aerosol An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be natural or Human impact on the environment, anthropogenic. Examples of natural aerosols are fog o ...
s, dust and vapor 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, coma or death. Developmental effects have been associated with pesticides. Recent increases in childhood cancers in throughout North America, such as leukemia, may be a result of
somatic cell A somatic cell (from Ancient Greek σῶμα ''sôma'', meaning "body"), or vegetal cell, is any biological cell forming the body of a multicellular organism other than a gamete, germ cell, gametocyte or undifferentiated stem cell. Such cells compo ...
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 size in animals and can produce undescended testicles. 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 Beneficial may refer to: Organizations * Beneficial Corporation, a consumer finance company founded in 1914 that was ultimately bought by HSBC Corporation ** Beneficial Loan Society, the former name of Beneficial Corporation ** Beneficial Finance, ...
predator or parasite can flourish should an insecticide application kill both pest and beneficial populations. A study comparing
biological pest control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...
and pyrethroid insecticide for diamondback moths, a major
cabbage Cabbage, comprising several cultivars of ''Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.&nb ...
family insect pest, showed that the pest population rebounded due to loss of insect predators, whereas the biocontrol did not show the same effect. Likewise, pesticides sprayed to control mosquitoes 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 Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lam ...
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 pheromones, 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 can also be an innovative way to control pests. Strains can be genetically modified (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 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 pollutants (POPs), such as
endosulfan Endosulfan is an off-patent organochlorine insecticide and acaricide that is being phased out globally. It became a highly controversial agrichemical due to its acute toxicity, potential for bioaccumulation, and role as an endocrine disruptor. ...
, 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 Pesticides in the United States are used predominantly by the agricultural sector,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 Depa ...
* Health effects of pesticides


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,