Effects on biota

Animals
Pesticides inflict extremely widespread damage to biota, and many countries have acted to discourage pesticide usage through their Biodiversity Action Plans.[citation needed]
Animals may be poisoned by pesticide residues that remain on food after spraying, for example when wild animals enter sprayed fields or nearby areas shortly after spraying.
Widespread application of pesticides can eliminate food sources that certain types of animals need, causing the animals to relocate, change their diet, or starve. Poisoning from pesticides can travel up the food chain; for example, birds can be harmed when they eat insects and worms that have consumed pesticides.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.
The USDA and USFWS estimate that about 20% of the endangered and threatened species in the US are , by use of pesticides.

Effects on biota

Plants
Nitrogen fixation, which is required for the growth of higher plants, is hindered by pesticides in soil.The insecticides DDT, 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 every year.
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%.

Soil effectance by pesticides

Many of the chemicals used in pesticides are persistent soil contaminants, whose impact may endure for decades and adversely affect soil conservative.
The use of pesticides decreases the general biodiversity in the soil. Not using the chemicals results in higher soil quality,[verification needed]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.

Soil effection by pesticides

Many of the chemicals used in pesticides are persistent soil contaminants, 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,[verification needed]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.

Water pesticides

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.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 in order 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, presence of a growing crop, and the method used to apply the chemical.
Maximum limits of allowable concentrations for individual pesticides in public bodies of water are set by the Environmental Protection Agency in the US. Similarly, the government of the United Kingdom sets Environmental Quality Standards (EQS), or maximum allowable concentrations of some pesticides in bodies of water above which toxicity may occur.The European Union also regulates maximum concentrations of pesticides in water.

Air

Pesticides:


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.Pesticides that are applied to crops can volatilize and may be blown by winds into nearby areas, potentially posing a threat to wildlife.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.Such windbreaks are legally required in the Netherlands.
Pesticides that are sprayed onto fields and used to fumigate soil can give off chemicals called volatile organic compounds, which can react with other chemicals and form a pollutant called ozone, accounting for an estimated 6% of the total ozone production.

Use of pesticides

Contents

1 Air
2 Water
3 Soil
4 Effects on biota
4.1 Plants
4.2 Animals
4.2.1 Birds
4.2.2 Aquatic life
4.2.3 Amphibians
4.2.4 Humans
5 Persistent organic pollutants
6 Pest resistance
7 Pest rebound and secondary pest outbreaks
8 Eliminating Pesticides

Use of pesticides can have unintended effects on the environment.
Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including nontarget species, air, water, bottom sediments, and food.Pesticide contaminates land and water when it escapes from production sites and storage tanks, when it runs off from fields, when it is discarded, when it is sprayed aerially, and when it is sprayed into water to kill algae.The amount of pesticide that migrates from the intended application area is influenced by the particular chemical's properties: its propensity for binding to soil, its vapor pressure, its water solubility, and its resistance to being broken down over time.Factors in the soil, such as its texture, its ability to retain water, and the amount of organic matter contained in it, also affect the amount of pesticide that will leave the area.Some pesticides contribute to global warming and the depletion of the ozone layer.