How does pesticide affect a human

Hazard, or risk, of using pesticides is the potential for injury, or the degree of danger involved in using a pesticide under a given set of conditions. Hazard depends on the toxicity of the pesticide and the amount of exposure to the pesticide and is often illustrated with the following equation:.

The toxicity of a pesticide is a measure of its capacity or ability to cause injury or illness. The toxicity of a particular pesticide is determined by subjecting test animals to varying dosages of the active ingredient a. The active ingredient is the chemical component in the pesticide product that controls the pest. By understanding the difference in toxicity levels of pesticides, a user can minimize the potential hazard by selecting the pesticide with the lowest toxicity that will control the pest.

Applicators may have little or no control over the availability of low-toxicity products or the toxicity of specific formulated products. However, applicators can minimize or nearly eliminate exposure--and thus reduce hazard--by following the label instructions, using personal protective clothing and equipment PPE , and handling the pesticide properly.

For example, more than 95 percent of all pesticide exposures come from dermal exposure, primarily to the hands and forearms. By wearing a pair of unlined, chemical-resistant gloves, this type of exposure can be nearly eliminated. Acute toxicity of a pesticide refers to the chemical's ability to cause injury to a person or animal from a single exposure, generally of short duration. The harmful effects that occur from a single exposure by any route of entry are termed "acute effects.

Acute toxicity is determined by examining the dermal toxicity, inhalation toxicity, and oral toxicity of test animals. In addition, eye and skin irritation are also examined. Acute toxicity is measured as the amount or concentration of a toxicant--the a. This measure is usually expressed as the LD 50 lethal dose 50 or the LC 50 lethal concentration LD 50 and LC 50 values are useful in comparing the toxicities of different active ingredients and different formulations containing the same active ingredient.

The lower the LD 50 or LC 50 value of a pesticide product, the greater its toxicity to humans and animals. Pesticides with a high LD 50 are the least toxic to humans if used according to the directions on the product label. The chronic toxicity of a pesticide is determined by subjecting test animals to long-term exposure to the active ingredient.

Any harmful effects that occur from small doses repeated over a period of time are termed "chronic effects. The chronic toxicity of a pesticide is more difficult than acute toxicity to determine through laboratory analysis. Products are categorized on the basis of their relative acute toxicity their LD 50 or LC 50 values.

Pesticides that are classified as highly toxic Toxicity Category I on the basis of either oral, dermal, or inhalation toxicity must have the signal words DANGER and POISON printed in red with a skull and crossbones symbol prominently displayed on the front panel of the package label.

For example, exposure of a few drops of a material taken orally could be fatal to a pound person. Some pesticide products have just the signal word DANGER, which tells you nothing about the acute toxicity, just that the product can cause severe eye damage or severe skin irritation. A teaspoon to an ounce of this material could be fatal to a pound person. An ounce or more of this material could be fatal to a pound person. Table 1 summarizes the LD 50 and LC 50 values for each route of exposure for the four toxicity categories and their associated signal word.

Pesticide labels and MSDS can be obtained from retailers or manufactures. In addition, most products also have information that can be found on the Internet. The symptoms of pesticide poisoning can range from a mild skin irritation to coma or even death. Different classes or families of chemicals cause different types of symptoms. Individuals also vary in their sensitivity to different levels of these chemicals.

Some people may show no reaction to an exposure that may cause severe illness in others. Because of potential health concerns, pesticide users and handlers must recognize the common signs and symptoms of pesticide poisoning. The effects, or symptoms, of pesticide poisoning can be broadly defined as either topical or systemic.

Dermatitis, or inflammation of the skin, is accepted as the most commonly reported topical effect associated with pesticide exposure. Some individuals tend to cough, wheeze, or sneeze when exposed to pesticide sprays.

Some individuals react to the strong odor and irritating effects of petroleum distillates used as carriers in pesticide products.

One symptom is that the eyes, mucous membranes of the nose, and even the sensitive linings of the mouth and back of the throat feel raw and scratchy. This symptom usually subsides within a few minutes after a person is removed from the exposure to the irritant. However, a reaction to a pesticide product that causes someone not only to sneeze and cough but also to develop severe acute respiratory symptoms is more likely to be a true hypersensitivity or allergic reaction.

Symptoms of a true allergic reaction range from reddening and itching of the eyes and skin to respiratory discomfort often resembling an asthmatic condition. Systemic effects are quite different from topical effects. They often occur away from the original point of contact as a result of the pesticide being absorbed into and distributed throughout the body.

Systemic effects often include nausea, vomiting, fatigue, headache, and intestinal disorders. In advanced poisoning cases, the individual may experience changes in heart rate, difficulty breathing, convulsions, and coma, which could lead to death.

Be alert for the early signs and symptoms of pesticide poisoning in yourself and others. These often occur immediately after exposure, but they could be delayed for up to 24 hours. If you are having symptoms but are unsure if they are pesticide related, at least notify someone in case your symptoms become worse.

But when symptoms appear after contact with pesticides, you should seek medical attention immediately. At this time, call the National Poison Center at for guidance on the proper response to your symptoms. This number will direct your call to the nearest poison center, which is staffed on a hour basis. If safe to do so, take the pesticide container to the telephone. However, if the pesticide container is contaminated, write down the product name, active ingredient s and percentage, and the EPA registration number.

The product label provides medical personnel information such as active ingredients, an antidote, and an emergency contact number for the manufacturer. If the Material Safety Data Sheet is available, take this also because it contains additional information for medical personnel. If you must go to the hospital or doctor's office, take the entire pesticide container, including the label, with you.

In order to avoid inhaling fumes or spilling the contents, make sure the container is tightly sealed and place into a plastic bag if possible. The pesticide container should never be placed in the enclosed passenger section of your vehicle. The acute toxicity of fungicides to humans is generally considered to be low, but fungicides can be irritating to the skin and eyes.

Inhalation of spray mist or dust from these pesticides may cause throat irritation, sneezing, and coughing. Chronic exposures to lower concentrations of fungicides can cause adverse health effects. Most cases of human fungicide poisonings have been from consumption of seed grain. To prevent these types of poisonings, fungicide treatment now includes a brightly colored dye to clearly indicate that the seed has been treated.

Table 2 summarizes the signs and symptoms of acute exposures to commonly used fungicides. In general, herbicides have a low acute toxicity to humans because the physiology of plants is so different than that of humans. However, there are exceptions; many can be dermal irritants since they are often strong acids, amines, esters, and phenols.

Inhalation of spray mist may cause coughing and a burning sensation in the nasal passages and chest. Prolonged inhalation sometimes causes dizziness. Ingestion will usually cause vomiting, a burning sensation in the stomach, diarrhea, and muscle twitching.

Table 3 summarizes the signs and symptoms of acute exposures to commonly used herbicides. Insecticides cause the greatest number of pesticide poisonings in the United States. The most serious pesticide poisonings usually result from acute exposure to organophosphate and carbamate insecticides.

Organophosphate insecticides include chlorpyrifos, diazinon, dimethoate, disulfoton, malathion, methyl parathion, and ethyl parathion. The carbamate compounds include carbaryl, carbofuran, methomyl, and oxamyl. Organophosphates and carbamates inhibit the enzyme cholinesterase, causing a disruption of the nervous system. Organic or biopesticides are created in nature but may be reproduced in labs. Although natural, these are not always safe for humans or the environment.

Some examples include measuring levels in people who were accidentally exposed to too much pesticide, animal testing, and studying the long-term health of people who use pesticides in their jobs.

Department of Agriculture, and Food and Drug Administration use this information to create a threshold for exposure that is considered safe. Several regulatory organizations establish safety limits for pesticides in the food supply. These limits are very conservative, restricting pesticides to many times lower than the lowest dose known to cause harm. There are several issues with the tools and procedures used to determine safety limits for pesticide use. For starters, some researchers have pointed out that regulatory agencies often rely on incomplete or inconsistent data to establish pesticide safety limits 4.

However, after another analysis was performed using additional data that was omitted from the initial report, researchers determined that the correct NOAEL was actually much lower, at 0. Many regulatory authorities also depend on data supplied from industry-funded studies to determine toxicity levels, which are often misleading and may have a higher likelihood of bias 6.

Another issue with pesticide safety limits is that some pesticides — synthetic and organic — contain heavy metals like copper, which build up in the body over time. In fact, one study in people found that vineyard farmers had 2—4 times higher levels of heavy metals like lead, zinc, and copper in their blood due to pesticide use compared with a control group 7.

On the other hand, a study of soil in India found that pesticide use did not result in higher levels of heavy metals than those found in pesticide-free soil 8. Another criticism is that some of the more subtle, chronic health effects of pesticides may not be detectable by the types of studies used to establish safe limits.

For this reason, ongoing monitoring of health outcomes in groups with unusually high exposures is important to help refine regulations. Violations of these safety thresholds are relatively uncommon. A Canadian study evaluated the amount of glyphosate in 3, samples of fruits, vegetables, grains, and baby foods and found that only 1. Furthermore, a report from the European Union found that Pesticide safety limits are often established using incomplete data or industry-funded studies.

Although more research is needed, pesticide use may also contribute to the buildup of heavy metals in the body, and other long-term health effects of pesticides can be difficult to detect. Both synthetic and organic biopesticides have harmful health effects at doses higher than those typically found in fruits and vegetables. According to one study in over 30, female spouses of pesticide applicators, increased exposure to organophosphates was linked to a significantly higher risk for hormone-related cancers, such as breast, thyroid, and ovarian cancer Another review of human, animal, and test-tube studies had similar findings, reporting that exposure to organophosphate pesticides like malathion, terbufos, and chlorpyrifos may be associated with a higher risk of developing breast cancer over time Some studies have also found that pesticide use may be tied to an increased risk of several other types of cancer, including prostate, lung, and liver cancer 15 , 16 , In fact, accidental exposures to high levels of pesticides in children are associated with cancer, attention deficit hyperactivity disorder ADHD , and autism 18 , Plus, according to one review, even low levels of pesticide exposure could negatively affect neurological and behavioral development in children In this study, it was unclear whether the pesticides detected in urine were from produce or other environmental exposures, such as living near a farm.

Another study showed that prenatal exposure to certain types of pesticides was associated with a higher chance for autism spectrum disorder, especially if exposure occurred within the first year of life On the other hand, a study showed no negative health effects in infants born to women with higher urine pesticide levels during pregnancy, compared with mothers with lower pesticide levels Some studies show that pesticide exposure could be linked to a higher chance of being diagnosed with cancer, ADHD, and autism spectrum disorder, although more research is needed.

The World Health Organization developed a comprehensive review of pesticides. However, the levels were not high enough to cause harm, even in children. In a review published by the European Union, approximately 2. Similarly, a Canadian report found that 1. The levels of pesticides can be reduced by cooking or processing foods. Peeling or trimming fruits and vegetables can also remove pesticide residues from the outer skin, although it may also decrease the nutritional value 26 , Still, washing produce with water may not be the most effective method for removing pesticide residue, as pesticides often penetrate deep into fruits and vegetables and may require the use of commercial cleaning solutions 27 , Pesticide levels in conventional produce are almost always below their safety limits.

They can be reduced further by cooking, processing, or peeling foods. Not surprisingly, organic produce has lower levels of synthetic pesticides, which translates into lower synthetic pesticide levels in the body One study in over 4, adults showed those reporting at least moderate use of organic produce had lower synthetic pesticide levels in their urine One older study of olives and olive oils using organic pesticides found increased levels of the biopesticides rotenone, azadirachtin, pyrethrin, and copper fungicides These organic pesticides also have negative environmental effects, which, in some cases, are worse than synthetic alternatives Exposure Exposure to pesticides can occur in many ways.

Should you be concerned? Acute toxicity Pesticides can be acutely toxic. Chronic or long term toxicity Pesticides can cause harmful effects over an extended period, usually following repeated or continuous exposure at low levels.

Health News:. Expectant mothers and children are most vulnerable to pesticides — find out why. Endocrine disruptors The term endocrine disruptor refers to substances that interfere with hormones and hormone balance. Carcinogenic substances A substance is considered carcinogenic when there is evidence that it can cause cancer. Combined effects One of the most worrying issues related to pesticide exposure is the fact that the effects of individual chemicals can be enhanced or altered when combined with one or more other such substances.

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