Why is it a problem?


Chlorpyrifos targets the nervous system of insects, but it is also “moderately” toxic to humans. It is very toxic to birds and insects, including bees. 

Chlorpyrifos has been linked to adverse brain development in unborn children and reduced IQ, loss of memory and attention deficit disorders in children. It has also been associated with measurable cognitive deficits and developmental delays in children exposed during early fetal and infant development.

In 2012 it was discovered that children have much lower levels of a detoxifying enzyme ‘paraoxonase 1’, than previously realised.  Paraoxonase 1 helps adult bodies get rid of organophosphate chemicals. Children remain susceptible until 7 years of age.

OP pesticides, such as chlorpyrifos can impair the brain’s prefrontal cortex, by shrinking. Behavioural problems can then occur as well as later life learning and social problems.

Workers exposed to chlorpyrifos can experience vomiting, muscle cramps, twitching, tremors and weakness.

According to the APVMA: “…cholinesterase inhibition remains the most sensitive and relevant adverse effect caused by chlorpyrifos and is therefore the most appropriate endpoint for the establishment of health based guidance values used to protect the entire population including pregnant women, infants and children… The inhibition of an enzyme critical for transmitting nerve signals is accepted by toxicologists, chemical regulators and the World Health Organisation (WHO) as the most sensitive adverse effect resulting from exposure to OPs, including chlorpyrifos. This enzyme, called acetylcholinesterase (AChE), is found in both the brain and blood and is specifically involved in maintaining normal nerve function. The statistically significant inhibition of this enzyme by greater than 20% below baseline is considered adverse and forms the basis of the health standards set for most OPs around the world. If the level of inhibition of AChE gets too high, people will begin displaying overt signs of poisoning”.

Acceptable Daily Intake (ADI) for Chlorpyrifos is 0.003 mg/kg body weight/day. The ADI is the amount that can be consumed “safely” in one day over a life time. (to put this into comparison with Glyphosate for example, the ADI for Chlorpyrifos is 100 times less than Glyphosate)

Acute Reference Dose (ARfD) for Chlorpyrifos is 0.1 mg/kg body weight/day. The ARfD is the amount that can be consumed “safely” in one meal.