Impacts of pesticides on our health

Pesticides are poisons and, unfortunately, they can harm more than just the “pests” at which they are targeted. They are toxic, and exposure to pesticides can cause a number of health effects. They are linked to a range of serious illnesses and diseases from respiratory problems to cancer.


Exposure to pesticides can occur in many ways. Farmers and farm workers can be exposed to pesticides in agriculture through the treatment of crops, plants and grain stores. Rural residents living next door to farms can be exposed to pesticide drift. Exposure can also occur in forestry, professional and domestic pest control, through the treatment of wood with preservatives, the treatment of boat hulls with anti-fouling agents, and the treatment of livestock with anti-parasitic preparations, e.g. sheep dip. In our towns and cities we are exposed to pesticides through the spraying of amenities, such as our parks, pavements and playgrounds. Many people buy pesticides off the shelf for home and garden use. And finally, pesticide residues found on, and in, our food also puts us at risk.

Should you be concerned?

Acute toxicity

Pesticides can be acutely toxic. This means that they can cause harmful or lethal effects after a single episode of ingestion, inhalation or skin contact. The symptoms are evident shortly after exposure or can arise within 48 hours. They can present as:

  • respiratory tract irritation, sore throat and/or cough
  • allergic sensitisation
  • eye and skin irritation
  • nausea, vomiting, diarrhoea
  • headache, loss of consciousness
  • extreme weakness, seizures and/or death

Chronic (or long term) toxicity

Pesticides can cause harmful effects over an extended period, usually following repeated or continuous exposure at low levels. Low doses don’t always cause immediate effects, but over time, they can cause very serious illnesses.

Long term pesticide exposure has been linked to the development of Parkinson’s disease; asthma; depression and anxiety; attention deficit and hyperactivity disorder (ADHD); and cancer, including leukaemia and non-Hodgkin’s lymphoma.

Pesticide effects on women and children

Endocrine disruptors

The term endocrine disruptor refers to substances that interfere with hormones and hormone balance. Hormones are the chemical messengers of the body. They are necessary to regulate different functions, in particular growth and reproductive functions.

The endocrine effects can be activated by very low concentrations of chemicals. They can manifest as:

  • reduced semen quality with consequent decreased fertility, genital malformations, testicular and prostate cancer
  • early puberty, appearance of cysts in the ovaries, uterus anomalies, breast cancer, pregnancy complications with early abortions, decreased fertility
  • diabetes and obesity
  • neurological disorders, especially disorders in brain development, and degenerative diseases in the brain, such as Parkinson’s disease
  • hyper and hypo thyroidism and thyroid tumours.

Carcinogenic substances

A substance is considered carcinogenic when there is evidence that it can cause cancer. There are many different types of cancer, but all of them can be characterised by the development of abnormal cells that begin to divide without control and spread into surrounding tissues. Single exposure events rarely cause cancer but repeated contact (whether through ingestion or the eyes, skin or lungs) with the carcinogenic substance, even at very low doses, can lead to 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. It is often referred to as the ‘cocktail effect’. Every day we are exposed to a cocktail of chemicals and the fact is that nobody knows what impact this consistent low level exposure to such a mixture of chemicals is having on us.  Not only are the effects not understood, there is no attempt within current pesticide regulation to address the issue since our system only assesses the safety of individual chemicals. We are, in effect, being experimented on.

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