Chlorpyrifos is a widely used insecticide which has been used in Australia since the mid 1960’s. It is used mainly on fruit and vegetable crops, but was also used in households and gardens up until the 2000’s. It is still registered for use across Australia for termite control.=
Chlorpyrifos is a broad spectrum1, non-systemic2 organophosphorous insecticide with contact, stomach and respiratory action. It acts by inhibiting the enzyme, acetyl cholinesterase (AChE), which is important for the transmission of nerve signals.
1broad spectrum means it can kill a wide range of insects.
2 Non-systemic means a contact pesticide, which is absorbed through the body of the insect. It also means that the insecticide will not be absorbed throughout the plant that the insect is eating.
Chlorpyrifos is used to kill insects, including scale, aphids, mealy bugs, leaf rollers, cutworms, grasshoppers, weevils, army worms, cockroaches, grubs, moths, flies, termites, ants, mites, spiders, mosquitos, lice etc. It is used as an insecticide on grain, cotton, field, fruit, nut and vegetable crops, and well as on lawns and ornamental plants.
According to the Australian Pesticides and Veterinary Medicines Authority (APVMA), Australia’s pesticide regulator:
“In January 2000, the APVMA (then known as NRA) released a Chlorpyrifos interim review report which summarised the outcomes of interim chemistry, agricultural, toxicological, occupational health and safety and environmental assessment reports. The report found that some home and garden formulations of chlorpyrifos could pose an unacceptable health and safety risk and that there were potential environmental concerns, particularly for birds and fish. As a result, several regulatory measures were implemented including label amendments with updated directions for use, first aid and safety directions, and environmental warning statements.”
There are approximately 135 products containing Chlorpyrifos, which are registered by the APVMA. The chemical has been under a review process in Australia since 1996.
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.
In 2012 Friends of the Earth attempted to determine which were the most commonly detected pesticides on Australian food (*3). Chlorpyrifos and Chlorpyrifos Methyl (*4) were the second and fourth most commonly detected pesticides. Chlorpyrifos was also the most commonly detected pesticide detected on food imports at this time, particularly on peanut products imported from China.
(*3) The Dose Makes the Poison, Friends of the Earth (accessed here)
(*4) There are 13 registered products containing Chlorpyrifos Methyl in Australia. Chlorpyrifos Methyl is used as a control for insects in stored grain and lupins (except for maize, malting barley and rice) and on surfaces of buildings, bins and machinery used for grain storage (except rice).
Chlorpyrifos has also been detected in many different locations across Australia, including waterways and drinking water catchments. See map here.
Chlorpyrifos has been linked to a number of fish kills and has been detected in many waterways across Australia. Chlorpyrifos has a remarkably low ecological water guideline of 0.00004 parts per billion, meaning that even at levels this low, it can have an ecological impact on freshwater ecosystems.
In 2019 Friends of the Earth wrote to Aldi, Coles and Woolworths supermarkets asking them about pesticide use and vegetables. You can view our full letter here.
The most detailed response was given by Coles, with the least detail provided by Aldi..
Both Coles and Woolworths said that the Maximum Residue Level (MRL) for each residue is contained in the Australian New Zealand Food Standards Code, administered by Food Standards Australia New Zealand (FSANZ). Coles claimed that FSANZ conduct risk assessments on chemicals and deliberately sets the MRL’s very conservatively so there is no possibility of a consumer exceeding Acceptable Daily Intakes (ADIs).
Coles added that growers supplying Coles regularly test their produce through industry programs to ensure they do not exceed legal limits and that Coles conducts monthly independent surveillance verification testing of fresh produce through an accredited laboratory. Over the past 3 years, Coles has facilitated over 100,000 residue tests. No details were given about the results of any of these tests or compliance details as this information is confidential.
You can see their responses here.
Chlorpyrifos was used to control insect infestations of homes and commercial buildings. These uses were banned in the United States in 2000 and in Europe, later in decade. South Africa banned this application in 2010. Singapore restricted its use as a termite control in 2009.
In 2010, India barred Dow from commercial activity for 5 years after India’s Central Bureau of Investigation found Dow guilty of bribing Indian officials in 2007 to allow the sale of chlorpyrifos.
Chlorpyrifos has not been permitted for agricultural use in Sweden at all (usage as a pest controllant is an exception - the last approval ran out in August 2008). A number of restrictions have occurred in a number of countries, most notably Hawaii which in June 2018 signed a bill banning chlorpyrifos in manufacturing, distribution and use. Hawaii was the first US state to enact such bans. California followed Hawaii’s decision in May 2019.
In January 2000, the predecessor of the APVMA, the NRA published an interim review report which in turn placed restrictions on home and garden use of chlorpyrifos. Additional residue findings, led to label changes in 2009. A supplementary toxicological assessment report was completed in April 2017 and a final review of the published science was expected to be published by the APVMA in August 2018. It appears unlikely that the APVMA will ban Chlorpyrifos.
1. Send an email to Woolworths telling them that it is not okay to keep selling food that may be contaminated by chlorpyrifos. We need to return to more organic practices, like we did before the uptake of industrial agricultural practices mid last century.
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