Pesticides and human health: Pesticides can cause short-term adverse health effects, called acute effects, as well as chronic adverse effects that can occur months or years after exposure. Examples of acute health effects include stinging eyes, rashes, blisters, blindness, nausea, dizziness, diarrhea and death.

Pesticide resistance is an example of natural selection because the insects who survive the initial use due to a gene that enable them to resist the attack pass on the gene for pesticide resistance to their offspring. The pesticides become less and less effective every year because organisms adapt to them.

Pest species evolve pesticide resistance via natural selection: the most resistant specimens survive and pass on their acquired heritable changes traits to their offspring. Over 500 species of pests have evolved a resistance to a pesticide. Other sources estimate the number to be around 1,000 species since 1945.

We have simply caused pest populations to evolve, unintentionally applying artificial selection in the form of pesticides. Individuals with a higher tolerance for our poisons survive and breed, and soon resistant individuals outnumber the ones we can control.

Impact on environment Pesticides can contaminate soil, water, turf, and other vegetation. In addition to killing insects or weeds, pesticides can be toxic to a host of other organisms including birds, fish, beneficial insects, and non-target plants.

Overzealous use of synthetic insecticides led to numerous problems unforeseen at the time of their introduction, like acute and chronic poisoning of handlers, farm workers and even consumers as the pesticides may enter food chain (Fig 6.2); destruction of water life, birds and other wildlife; interruption of natural …

Pesticides in agriculture and urban settings have the potential to contaminate our air, affecting human, animal and plant health. Pesticides released into the air can settle to the ground, be broken down by sun light and water in the atmosphere, or dissipate into the surrounding air.

Pesticides are important. They help farmers grow more food on less land by protecting crops from pests, diseases and weeds as well as raising productivity per hectare. Production of major crops has more than tripled since 1960, thanks in large part to pesticides.

It is estimated that of the roughly 672 million birds exposed annually to pesticides on U.S. agricultural lands, 10%– or 67 million– are killed. This staggering number is a conservative estimate that takes into account only birds that inhabit farmlands, and only birds killed outright by ingestion of pesticides.

Pesticides and rodenticides are very useful for controlling mice and rat populations, termites and weeds, but can pose significant risks to wildlife. Animals like hawks, owls, squirrels, skunks, deer, coyotes, foxes, mountain lions, and bobcats can be killed by pesticides even though they are not the target.

The birds failed to put on the necessary weight to survive energy- draining migratory flights. The U.S. Fish and Wildlife Service estimates that an estimated 67 million birds die from pesticide poisoning each year and more than 600 million are exposed.

Species richness of beneficial insects, such as bees, spiders, and beetles, has been found to be much higher on untreated or organic fields than on those treated with insecticides.

Exposure to a particular pesticide may occur through multiple exposure routes (oral, dermal, and inhalation) depending on the type and use of the pesticide. Common sources of exposure to pesticides for the general population include residues in food and drinking water.

1. Incorrect use can result in wasted material, failure to control the pest, and damage to the target site. 2. Misused pesticides can cause immediate as well as long-term harmful effects to humans, to other living things, to property, and to other parts of the environment.

People can be exposed to pesticides in three ways: Breathing (inhalation exposure). Getting it into the mouth or digestive tract (oral exposure). Contact with the skin or eyes (dermal exposure).

Many insecticides can cause poisoning after being swallowed, inhaled, or absorbed through the skin. Symptoms may include eye tearing, coughing, heart problems, and breathing difficulties.

Pesticide half-lives can be lumped into three groups in order to estimate persistence. These are low (less than 16 day half-life), moderate (16 to 59 days), and high (over 60 days). Pesticides with shorter half-lives tend to build up less because they are much less likely to persist in the environment.

Fungicides were the most toxic from concentrations 300–600 times lower than agricultural dilutions, followed by herbicides and then insecticides, with very similar profiles in all cell types. Despite its relatively benign reputation, Roundup was among the most toxic herbicides and insecticides tested.

DDT was regarded as the most powerful pesticide the world had ever known and was widely used for ridding South Pacific islands of malarial insects during WW II and as a delousing powder in Europe. In the 1950s, it started being used in increasing amounts in the US as a means of controlling insect and pest populations.

S6 Pesticides: These have moderate toxicity and available to the public and also require caution in use, handling and storage. S7 Pesticides: These have high to very high toxicity. These pesticides are extremely hazardous and dangerous to health and have a high potential for causing harm at low exposures.

Regulation Due to Health and Environmental Effects In 1972, EPA issued a cancellation order for DDT based on its adverse environmental effects, such as those to wildlife, as well as its potential human health risks.

Is it safe? DDT was sprayed in America in the 1950’s as children played in the spray, and up to 80,000 tons a year were sprayed on American crops. There is some research suggesting that it could lead to premature births, but humans are far better off exposed to DDT than exposed to malaria.

DDT – Banned for crop use in the U.S. since 1972, DDT is still used in many countries.

Paraquat and phorate are the only two pesticides still used in the USA that are banned or being phased out in the EU, China and Brazil.

“Soft” chemicals: soap, stinging nettles, and rhubarbs provide excellent alternatives to pesticides. Parasites: certain pests are often easily targeted by specific parasites. Predators: ladybird beetles and birds will decimate many pest infestations in short order.

Two formulations of ethyl parathion are currently being sold in the United States: Parathion 8EC (emulsifiable concentrate) and Ethyl Methyl Parathion 6-3 EC. A third formulation, 4EC, is registered but is not currently marketed.

Illegal pesticides include products that are sold or distributed in the U.S. without being evaluated or registered by the EPA. For example, the company may request cancellation or the EPA could re-evaluate the product and remove uses based on current scientific knowledge of the risks.

The chalk is illegal because it never received the regulatory approval required of pesticides’ formulas and packaging. But many say it is far more effective and pleasant to use than the baits and sprays sold at supermarkets and hardware stores.

For instance, phorate, the most used “extremely hazardous” insecticide in the U.S. in 2017, is banned in 38 countries, including China, Brazil and India.

Mothballs are pesticides intended to kill clothes moths and other fabric pests. They are regulated in the United States by the Environmental Protection Agency. Using mothballs in a way not specified by the label is not only illegal, but can harm people, pets or the environment.