Use of pesticides came under scrutiny at a recent Royal Society of Medicine conference, with data on numbers of active ingredients (AIs) used on wheat, potatoes and onions extracted by Fera at the request of the Soil Association presented.
Professor Carlo Leifert, director, Centre for Organics Research, Southern Cross University, Australia, said the data showed that the average number of AIs used on wheat had increased from 1.7 in 1974 to 20.7 in 2014; potatoes from 5.3 in 1975 to 30.8 in 2014 and onions from 1.8 in 1966 to 32.6 in 2015.
The Crop Protection Association (CPA) said that the weight of pesticides applied to the above crops (kg of AI) has fallen by approximately 50% since 1990.
Soil Association policy advisor Peter Melchett, who spoke at the conference entitled Pesticides and food: is low dose exposure harmful? said: “In looking at the potency of pesticides, the number of toxic chemicals applied, rather than the weight, is relevant to whether consumers may find cocktails of pesticides in their food.
“We heard about evidence that eating a sequence of pesticides can make very low doses more toxic.”
The number of active ingredients available to farmers has increased over the last 40 years as a result of innovation, research and development, although the number of available AIs is now declining, said CPA CEO Sarah Mukherjee, who spoke at the conference. “Whilst the number of active ingredients used on these three crops has increased, the levels of residues found remains low.
“If you look at potatoes as an example, the Government’s Pesticide Residues in Food (PRiF) monitoring programme shows that in 2015 of 156 samples of potato, 73 samples contained no residues at all and only 31 contained residues of more than one pesticide.
“If anything, that proves our point; even with a supposed average of 30.8 AIs applied, 47% of potatoes sampled by PRiF contained no residues at all, 33% contained traces of only one pesticide and the highest number of residues was three.
“None contained residues above the MRL [Maximum Residue Limit].”
The existing risk assessment and management approaches under the regulations are effective in protecting human health from exposure to the low levels of residues present in food, said Ms Mukherjee.
“Managing the risks from these substances individually should ensure that combinations of substances do not present a concern for human health and the current risk assessment methodology used by regulators is conservative enough to take account of the potential impact of multiple residues.”
NFU acting chief science and regulatory affairs adviser Dr Chris Hartfield, who spoke at the conference, said a previous study on pesticides in the US diet showed 99.99% are naturally occurring compounds used by plants to fight off pests and diseases. “There is an artificial notion that any chemical that is natural is safe and any chemical that is manmade is dangerous – it is a completely false notion.”
The EU has one of the most robust pesticide regulatory systems in the world, he said. “There are very strict controls about what comes to market, how pesticides are applied and monitoring Maximum Residue Levels.”
Paying attention to improving the population’s fruit and vegetable intake could have a more significant impact on public health, he argued. “People should eat healthier, more balanced diets such as eating five a day. It doesn’t matter whether it’s produced organically or conventionally.”