Effects of Pesticides in the United States
1.0 Introduction
Pesticides are toxic chemical substances that are intentionally released into the environment to control or destroy harmful pests such as insects, rodents, weeds, and fungi among others. These substances work by attracting, luring, and then mitigating or destroying the pests. Pests can be described as animals or plants that compromise the quality and amount of food produce, health, and comfort. The application of pesticides has continued to grow decade after decade. According to Alavanja (2009), approximately 5.6 billion pounds of different types of pesticides are applied worldwide and over 1 billion pounds are used in the United States each year. It is also estimated that over 25 million workers in the world are exposed to unintended pesticide poisoning annually.
In the United States, statistics show that 16% of the American agricultural workers have had at least 1 pesticide poisoning. In recent decades, the use of pesticides has extended from agricultural fields to homes in the form of poisons, sprays, and powders to control rats, ticks, mosquitoes, fleas, and other harmful bugs. Once these substances are released into the environment, they are broken down into metabolites that have more toxicity. Although their use promises an effective way of mitigating harmful pests, the associated risks are of overarching concerns (Langley & Mort, 2012). This informative research seeks to discuss the hazardous effects of pesticides in the United States. The continued non-regulation of pesticides has led to disastrous consequences on the environment raising severe concerns on human health, biodiversity, and ecosystems.
- Background
- 1 Pesticides Registration and Safety
Registration of pesticides is has a complex administrative and legal process that requires huge resources, skills, and time. During the process, all the potential human health, as well as environmental effects, is assessed to ensure the safety of the ingredients used to manufacture the pesticide. The registration process is rigorous to ensure that the products that are released into the market are authorized as well as are utilized for the intended purpose (Mahmood et al. 2016). The process helps the relevant authorities to enact control over aspects such as quality, safety, packaging, pricing, labeling, and advertising to ascertain the profound protection of the interest of the users. In this case, the manufacturers are required to carry thorough research and analyze exhaustive tests before applying for registration or even data reporting. The tests are meant to gauge all potential risks on animals, humans, plants, and other non-target entities in the environment (Langley & Mort, 2012). The registration process is illustrated in figure 1 below.
Figure 1: Steps of registering a pesticide (Mahmood et al. 2016)
The registration application includes several aspects such as chemical and physical properties of the used ingredients, proposed toxicity, analytical methods applied, associated hazards, recommended labels, intended use, storage, and disposal protocols. The application is reviewed and evaluated and after careful human, environment, and biodiversity risks assessment are conducted, the United States Environmental Protection Agency approves or rejects the pesticide product accordingly. The body also ensures that all the registered pesticides continue to meet the set safety standards (Mahmood et al., 2016).
2.2 Classification of Pesticides
Based on the intended use, a pesticide can be categorized as a repelling, destroying, or mitigating agent. However, due to the current over usage, pests are starting to get immune to commercial pesticides. Still, these commercial pesticides are the dominant agents for managing pests. The effects of these agents on the intended targets depend on the amount of toxicity and duration of exposure as well as other scaled-down factors such as life history, the timing of application, landscape structure, and population structure. The common categories include insecticides, fungicides, herbicides, rodenticides, nematicides, and molluscicides among others. All these categories pose toxicity risk not only to people who use them for agricultural purposes but also for workplaces and industries. Depending on the target pests, pesticides can cause a threat to natural fauna, flora, and aquatic life (Mahmood et al., 2016).
3.0 Risks Associated with the Use of Pesticides
Each category of pesticides has drastic effects on the non-targeted species; affecting animals and plants biodiversity, terrestrial and aquatic food webs as well as ecosystems. According to Mahmood et al. (2016), nearly all the used pesticides volatilize within a short time. The volatilized substances evaporate into the atmosphere which subsequently may endanger the non-target species. A good example is the continued application of herbicide products, volatilize off the targeted plants which may cause damage to other nearby plants. Therefore, the uncontrolled application of pesticides has led to the decline of numerous aquatic and terrestrial plant and animal species. The survival of rare species like osprey, bald eagle, and peregrine falcon has also been threatened. More so, soil, air, and water bodies have also been jeopardized by these chemicals to substantial toxic levels.
3.1 Threats to Biodiversity
Pesticides contain toxin and the risks posed by uncontrolled use of these chemicals cannot be underestimated. In the United States, the use of pesticide threatens biodiversity since it disrupts the terrestrial and aquatic life. Consumption of toxins contained in pesticides threatens the life of birds, animals, and plants. Raptors and predators are affected directly when pesticides accumulate in the food chain while the indirect outcome of pesticides includes reduction of shrubs, harmful weeds, and insects which are primarily fed by the higher orders. Increased use of herbicides, insecticides, and fungicides in the United States has been strongly associated with the reduction of the rare populations of some species of birds and animals (Mahmood et al., 2016). Furthermore, the continued use of pesticides for a long time leads to bioaccumulation.
3.1.1 Risk to Aquatic life
There are various ways in which pesticides get into the water, for example, direct application on water surfaces, leaching in the soil, runoff, and drift. Water contaminated with harmful elements of pesticides threatens aquatic life. Chemicals in water reduce the ability of oxygen to dissolve thus causing both behavioral and psychological effects among the fish. Besides, these chemicals affect the water plants (Mahmood et al., 2016). Several studies in the United States indicate that most of the surface water and water bodies such as streams lakes and ponds contain pesticides used in lawn maintenance. Pesticides applied on the land drifts to water bodies and cause harm to fish and other non-targeted organisms living in waters. A continued decrease in species of fish has been observed in America due to the persistent use of pesticides. Aquatic animals consume pesticides by absorbing through the skin, breathing through the gills, and the oral cavity when drinking contaminated water (Isenring, 2010).
Aquatic life is sustained by dissolved oxygen provided by water plants. Therefore, when herbicides destroy these plants the amount of dissolved oxygen in water reduces drastically resulting in suffocation and reduced fish yields. Pesticides runoff from farm activities and spray drifts has been linked to high levels of pesticides in surface waters than groundwater in America. However, pesticides reach underground water through seepage, poor disposal, and accidental leakages (Isenring, 2010). Some elements of pesticides such as toxic Atrazine that drift into lakes and ponds directly affect the immune system of amphibians and are toxic to some species of fish. Pesticides on the surface waters greatly affect amphibians besides destroying their natural habitats. Several other elements in herbicides have been identified to cause various destructions to the aquatic ecosystem. Glyphosate is well known for causing high death rates among young frogs and tadpoles while malathion reduces the population and composition of periphyton and plankton plants in water thus hindering the growth of tadpoles. Additionally, herbicides destroy shelters for juvenile fish exposing them to predators thus reduce the reproductive potential of living organisms in water (Mahmood et al., 2016).
3.1.2 Risks to Terrestrial life
Spraying pesticides to terrestrial plants cause harmful effects and death to terrestrial life. Spraying pesticides such as phenoxy herbicides to plants affect other non-target plants nearby such shrubs and trees (Mahmood et al., 2016). Herbicides such as glyphosate have been found to reduce plant’s ability to resist infections from diseases and the quality of their seeds. Other studies indicate loss of productivity and destruction of wildlife as immediate effects of sulfonamides and imidazolinones herbicides exposure to terrestrial life.
The animal populations in the United States have been affected by pesticide exposure. Broad-spectrum herbicides like organophosphates and carbamates reduce the number of terrestrial insects such as beetles and bees. Farms adopting an organic form of farming have a great likelihood of having more insect populations compared to those practicing the inorganic farming method. Bees are the most affected insects when exposures to pesticides. It is established that exposure to some pesticides affects the bee’s ability to forage and produce quality, honey. Besides, some species of bees have become extinct due to exposure to toxins and consequently affected food production in industries that rely on pollination done by bees (Mahmood et al., 2016).
Accumulation of pesticides in bird tissues causes death and a decline in their population. In the United States, the population of Bald eagles reduced in the last century due to exposure to DDT chemicals and its elements. Some fungicides kill earthworms which is a primary source of food for mammals and birds, therefore, reducing the populations of birds and mammals indirectly (Mahmood et al. 2016). Herbicides are poisonous and once consumed by birds in the granular form they cause death and destruction of their body systems such as the nervous system leading to behavioral changes.
Plants largely depend on microbes residing in the soil for growth and development by breaking down organic matters, mineral uptake, and improving soil fertility. Once pesticides are applied in the soil through sprays or as liquids, they get leached and dissolve in the groundwater. Plants uptake these toxins through underground water and consequently die (Mahmood et al., 2016). Also, the death of soil microbes reduces the plant’s productivity and an overall decline in agricultural output. For instance, Glyphosate herbicide disrupts the ability of nitrogen-fixing bacteria in the soil causing limited uptake by plants while 2,4-D hinders the conversion of ammonia to nitrites by the soil bacteria (Mahmood et al., 2016).
Lastly, herbicides contribute to the death of earthworms in the soil. Earthworms assist in soil fertility and act as bio-indicators of contamination in the soil also it is a model for testing soil toxicity (Isenring, 2010). Herbicides cause damage to fungal organisms in the soil which facilitate mineral uptake by plants. This inhibits fungal processes such as symbiosis which is very necessary for mineral uptake by terrestrial plants.
3.2 Threat to Human Health
Pesticides seek to improve the quality of human health through mitigating vector-borne health conditions. Nonetheless, their indiscriminate and long-term application has resulted in significant health effects. Humans, especially children, and infants are greatly vulnerable to the toxic impacts of pesticides due to the inadequate application and non-specific nature of pesticides. As the application of these chemicals continues to increase with each decade, the level of exposure to toxicity increases. According to the WHO, approximately 3,000,000 pesticide poisoning cases and 200,000 deaths are reported annually in developing countries. In the US, approximately 20,000 patients receive emergency care due to pesticide poisoning every year (Mahmood et al. 2016). Pesticides enter the body through inhalation, ingestion, or skin penetration. Notably, the majority of victims get affected through ingestion via contaminated food. These substances ultimately find their way to the tissues and storage compartments (Kumar et al., 2012). Although the human body has toxins excretion mechanism, in some instances, chemicals are retained through the cardiovascular system’s absorption process. Hence, the toxic effects are created when the concentration of chemicals in the body exceeds the initial concentration in the environment. These effects may appear abruptly and severely (acute) or after months or years to manifest (chronic).
3.2.1 Acute Effects
There are numerous immediate health implications of pesticide exposure such as skin itching, blisters and rashes, headaches, dizziness, nausea, vomiting, and abdominal pains, blurred vision, stinging of the eyes, nose, and throat irritation and death. The acute effect may sometimes be severe enough for someone to have to seek emergency care (Mahmood et al., 2016).
3.2.2 Chronic effects
Chronic effects are mostly lethal and manifest for several years. In this case, chronic effects are long-term effects that harm or even cause total damage to human body organs. One of the consequences of prolonged pesticide exposure is the causation of neurological effects such as reduced motor signaling, reduced visual ability as well as the loss of memory and coordination. Another consideration is damage to the immune system which can lead to allergies, asthma, and hypersensitivity. More so, residues of pesticides have been seen in cancer patients’ bloodstream which has been associated with brain cancer, leukemia, brain cancer, prostate cancer, and lymphoma. Prolonged exposure to pesticides has also been linked to defects in reproductive capabilities through altering the amount of female and male hormones which leads to issues such as stillbirths, spontaneous abortion, infertility, and birth defects. Additionally, long-term exposure may damage organs such as kidneys, liver, and lung leading to health conditions such as blood diseases (Mahmood et al., 2016).
4.0 Proponents of Pesticides
It is argued that nearly 30% of the American agricultural produce is destroyed by weeds, pests, and diseases and therefore if there were no pesticides, the situation would have been more catastrophic. More so, pesticides are seen to protect crops and animals from damage from parts and increase agricultural production. Some studies have indicated a substantial increase in crop yields due to the persistent application of pesticides and shown economic losses associated with a lack of pesticide usage. The studies show that yields of bread grains have improved by 10% due to the usage of herbicides and increased pollination (Aktar, Sengupta & Chowdhury, 2009).
There claims that agricultural production would depreciate if plants and animals are not protected from the effects of pests. In this case, reduced food production would lead to shortages of essential foods and trigger the rise in food prices. Hence, pesticides may play a part in keeping food commodities prices afloat. Another important consideration is aflatoxins. Controlling insects plays a role in preventing the passage of toxins to crops from insects. Aflatoxins are carcinogens that cause damage to the liver, reduce the response of the body’s natural immune as well as impair growth in children (Aktar, Sengupta & Chowdhury, 2009). Therefore, crop herbicides are seen as perfect agents for controlling mediated aflatoxin contamination.
It is argued that pesticides augment sanitary conditions at home through keeping rodents, insects, and other bugs in check. These pesticides are seen to preserve the home as well as recreational spots aesthetics through preventing structural damage linked to termite infestation and weeds,. Other considerations include the preservation of pitches, turfs, and golf courses (Aktar, Sengupta & Chowdhury, 2009).
Nonetheless, the hazardous effects of pesticides outweigh the perceived benefits. The focus should be directed to applying non-toxic methods to control pests in the home and agricultural fields. Chemical pesticides can be combined with remedies and other natural treatments that have increased chances for the sustainable elimination of all kinds of pests. A well-thought combination fosters environmental sustainability and provides diverse methods of controlling invasive species. Pesticides pose a significant threat to marine and aquatic ecosystems. In this case, there is a need to integrate research from different disciplines such as conservation biology, community ecology toxicology, environmental chemistry, landscape ecology, epidemiology, and population biology to understand the direct as well as indirect effects of pesticides on human health and the environment.
4.0 Conclusion
The use of has proved to offer solutions associated with mitigating, controlling, and destroying pests. However, the numerous hazards posed to the environment and human health have raised concerns especially the safety of pesticides. The application of pesticides in the United States is continuing to increase which poses increases risks and complications. The number of pesticide poisoning cases keeps rising every day, with US accounting to 10% of the annual reported cases. Many farmers are not conversant with the level of toxicity in the products that they use. Most farmers are not aware of the different types of pesticides, risk of poisoning as well as the safety measures required before application. In this case, poisonous and environmentally unsafe chemicals are applied to destroy pests which also lead to incidental, intentional, or occupational exposure. These chemicals pose profound shorten and long-term threats to the environment and human health. Although hazards associated with the use of pesticides cannot be eliminated, various measures can be used to reduce and manage the imminent level of risks. Some of these measures include using alternative methods of growing crops, production of better and safer environmentally friendly pesticide formulations, appropriate usage of pesticides in terms of quantities and intended purpose, and lessened toxic formulation.
References
Aktar, W., Sengupta, D., & Chowdhury, A. (2009). Impact of pesticides use in agriculture: their benefits and hazards. Interdisciplinary toxicology, 2(1), 1-12.
Alavanja, M. C. (2009). Introduction: Pesticides use and exposure, extensive worldwide. Reviews on environmental health, 24(4), 303-310.
Isenring, R. (2010). Pesticides reduce biodiversity. Pesticides news, (88), 4-7.
Kumar, N., Pathera, A. K., Saini, P., & Kumar, M. (2012). Harmful effects of pesticides on human health. Annals of Agri-Bio Research, 17(2), 125-127.
Langley, R. L., & Mort, S. A. (2012). Human exposures to pesticides in the United States. Journal of agromedicine, 17(3), 300-315.
Mahmood, I., Imadi, S. R., Shazadi, K., Gul, A., & Hakeem, K. R. (2016). Effects of pesticides on environment. In Plant, soil and microbes (pp. 253-269). Springer, Cham.