Neonicotinoids: Persistent Organic Pollutants Or Not?

Neonicotinoids are a class of systemic insecticides widely used on food crops globally. They are among the most popular pesticides in the world due to their high toxicity to invertebrates, ease of application, and systemic nature. However, their widespread use has raised concerns about their persistence in the environment and potential impact on human health and ecosystems. Neonicotinoids have been detected in water, soil, pollen, honey, and food items, leading to questions about whether they are considered persistent organic pollutants (POPs). POPs are toxic organic compounds that adversely affect human health and the environment and have the ability to travel over long distances. They are often man-made and can accumulate in the environment, leading to potential biodiversity loss and health risks for sensitive populations. While neonicotinoids share some characteristics with POPs, such as persistence and potential toxicity, determining whether they are classified as POPs under the Stockholm Convention or other regulatory frameworks requires further investigation and analysis of their specific chemical properties and environmental impacts.

Neonicotinoids are a class of systemic insecticides

Neonicotinoids are often applied to plants using various methods, such as foliar sprays, seed treatments, and soil drenches. Their popularity stems from their high toxicity to invertebrates, ease of application, flexibility, and systemic nature, ensuring they spread to all parts of the target crop. However, these characteristics also increase the likelihood of environmental contamination and exposure of non-target organisms. For example, pollinators and aquatic insects are particularly susceptible to the effects of neonicotinoids, and research suggests that chronic sublethal effects are more prevalent than acute toxicity.

Neonicotinoids have been detected in the environment, including pollen, soil, water, and honey. Despite their controlled use, there are concerns about their impact on honey bees, with evidence suggesting they may impair bees' ability to forage for nectar and remember the location of flowers. Furthermore, neonicotinoids have been identified in human blood, tissue, urine, semen, bile, and brain matter, indicating the potential for extensive human exposure.

While neonicotinoids are effective against insects and certain pests, their widespread use has raised concerns about their negative effects on non-target organisms and the environment. As a result, future decisions on their use will need to balance crop yield benefits against potential environmental impacts and explore more environmentally benign alternatives.

They are widely used on food crops globally

Neonicotinoids are a class of systemic insecticides widely used on food crops globally. They are popular due to their high toxicity to invertebrates, ease and flexibility of application, long persistence, and systemic nature. Neonicotinoids are often applied as seed coatings, which can reduce overspray and drift. However, their prophylactic use as seed coatings goes against the principles of integrated pest management, which advocate avoiding broad-spectrum pesticides and only using them as a last resort.

Neonicotinoids are used on a variety of agricultural crops, including vegetables, fruits, rice, cotton, corn, soybeans, and sunflowers, among others. They are transported throughout the treated plant into the leaves, nectar, and pollen. Due to their water solubility, they can easily contaminate water supplies, and their residues have been detected in food, pollen, and water.

In the United States, neonicotinoid residues were detected in various food commodities between 1999 and 2015, including fruit, vegetable, meat, dairy, grain, honey, and baby food. The detection frequencies were generally below 20%, with similar average frequencies for domestic and imported commodities. However, more recent data and studies on the prevalence of neonicotinoid residues in the US food supply are limited.

The widespread use of neonicotinoids has raised concerns about their impact on the environment, wildlife, and human health. They have been linked to harmful effects on non-target organisms, such as bees and aquatic insects, leading to a decline in biodiversity. Neonicotinoids are also toxic to birds and can contaminate surface and groundwater, affecting aquatic life and bird populations.

To address these concerns, future decisions on neonicotinoid use should carefully weigh the benefits of crop yield against potential environmental impacts. Additionally, more extensive surveillance of food and water supplies and further research on cumulative daily intake in high-risk groups, such as pregnant women and infants, are warranted.

They are highly toxic to invertebrates

Neonicotinoids are a group of insecticides widely used on farms and in urban landscapes. They are highly water-soluble and can be absorbed into plants, making their way into pollen and nectar. This means they are very toxic to pollinators and beneficial insects that feed on them. They are also toxic to aquatic invertebrates, with neonicotinoid contamination of waterways being an emerging threat.

Neonicotinoids are highly toxic to invertebrates as they disrupt neural transmission in the central nervous system. They mimic the action of neurotransmitters, continuously stimulating neurons, which leads to the death of target invertebrates. This can cause paralysis and the depletion of cellular energy. They are particularly harmful to insects from the orders Ephemeroptera and Diptera.

The widespread use of neonicotinoids, combined with their water solubility, means that they are often found in water and soil samples. This has led to the contamination of waterways, putting aquatic invertebrates at risk. Neonicotinoids have been shown to have negative interactions with the normal physiology of aquatic organisms, causing reduced production of byssus, alteration of antioxidant systems, and tissue damage.

The use of neonicotinoids as seed coatings on major agricultural crops has led to their widespread detection in the environment. This has raised concerns about their impact on non-target organisms, including aquatic invertebrates. The popularity of neonicotinoids is due to their high toxicity to invertebrates, ease and flexibility of application, long persistence, and systemic nature. However, these properties also increase the likelihood of environmental contamination.

While neonicotinoids were initially introduced as less harmful than older insecticides, research has shown that they have devastating ecological impacts. Their use has been linked to a decline in flying insect biomass and wild bumble bee populations. The scale of their use means they may be having a considerable negative impact on bee populations across the developed world.

They are persistent in the environment

Neonicotinoids are a class of systemic insecticides widely used on food crops globally. They are among the most popular pesticides in the world, largely due to their high toxicity to invertebrates, ease and flexibility of application, systemic nature, and long persistence.

Neonicotinoids are designed to be absorbed into the target crop plant, but only 1.6–20% of the active ingredient is absorbed, with the majority remaining in the soil. This persistence in soil, water, and wild plants is a potentially serious environmental concern. If neonicotinoids move into habitats surrounding agricultural fields, they can affect a much greater range of organisms than just crop-visiting invertebrates.

Neonicotinoids have been detected in pollen, soil, water, honey, and wildflowers, demonstrating their widespread presence in the environment. They have also been found in ""off-target"" food items such as fruit, vegetables, meat, dairy, grain, honey, baby food, and organic commodities. The highest detection frequencies for neonicotinoids by year were generally below 20%cherries, apples, pears, and strawberries having higher detection frequencies of up to 45.9%.

The persistence of neonicotinoids in the environment is of concern because it increases the probability of environmental contamination and exposure of non-target organisms. Pollinators and aquatic insects appear to be especially susceptible to the effects of neonicotinoids, with current research suggesting that chronic sublethal effects are more prevalent than acute toxicity.

The widespread use of neonicotinoids may be having a considerable negative impact on wild bumblebee populations across the developed world. Treated bee colonies have shown significantly reduced growth rates and a decrease in the production of new queens. The environmental persistence of neonicotinoids, coupled with their toxic effects on non-target organisms, highlights the importance of weighing the benefits of crop yield against potential ecological harm.

They can contaminate waterbodies, soil, and food

Neonicotinoids are a class of systemic insecticides widely used on food crops globally. They are among the most popular pesticides in the world due to their high toxicity to invertebrates, ease of application, flexibility, and systemic nature. However, these same properties increase the likelihood of environmental contamination and exposure of non-target organisms.

Neonicotinoids have been detected in waterbodies, soil, and food items beyond their intended targets. They can contaminate water through various routes, including runoff from treated fields, leaching from treated seeds, and uptake by non-target plants through their roots. This water contamination poses risks to aquatic organisms, particularly insects, and can have chronic sublethal effects.

In terms of soil contamination, neonicotinoids can persist in the environment for extended periods, with detectable levels found in agricultural soils over a year after treated seeds were planted. This persistence in soil can result in chronic exposure for soil-dwelling organisms and can also lead to the uptake of neonicotinoids by wild plants, further expanding the range of affected organisms.

Neonicotinoids may also be present in food items beyond the crops they are applied to, including fruits, vegetables, meat, dairy, grain, honey, and baby food. This contamination can occur through various routes, such as dust generated during the drilling of treated seeds, residue on crops, or uptake by the roots of non-target plants. While the detection frequencies for neonicotinoids in food commodities are generally below 20%cherries, apples, and cauliflower, have shown higher detection rates for specific neonicotinoids.

The contamination of water, soil, and food by neonicotinoids has raised concerns about their potential impact on human health and the environment. While there is limited research on the prevalence of neonicotinoid residues in food, the available data suggest that their persistence in the environment may lead to chronic exposure for both humans and various organisms, potentially causing adverse effects.

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