Opinion: Many experts regard agrichemicals as a lifesaver and they have the facts to back it up. However, this doesn't stop people's concern over their use, Dr Jacqueline Rowarth writes.
Chemicals used in agriculture are termed "agrichemicals". They are also called "agrochemicals" which sounds worse.
But while a few people rant about their existence, many experts regard them as just as much of a lifesaver as, for instance, the development of antibiotics and vaccines.
A series of articles published by geneticliteracyproject.org (a website with the strapline "science not ideology") presents facts clearly.
"By any of the standard measures of public health – reductions in mortality, impairment, and infectious diseases, as well as improved quality of life – the contribution of modern pesticides has been profound".
Author Henry I. Miller, is a physician, a molecular biologist and the founding director of the US Food and Drug Administration's Office of Biotechnology.
Farmers have always used chemical pesticides.
Up until World War II the chemicals were mostly compounds containing sulphur and heavy metals such as copper.
Some of these, such as copper sulphate, are still approved in organic production systems. Copper sulphate is highly toxic, relatively indiscriminate, and long lasting.
Advances in organic (carbon-based) chemistry have allowed development of targeted pesticides to replace broad spectrum application. Successful targeting of intended pests means that the chemicals are far less toxic to non-target species.
The US Department of Agriculture has calculated that pesticides have become less toxic, more potent (leading to lower application rates), and less persistent in the environment since the 1960s.
Yet the concerns continue.
Media coverage of bee-pocalypse blaming chemical use by farmers fails to cover the real issues which are increasingly those of inadequate feeding during winter and overstocking in other seasons.
Most countries have had rapid increases in the number of managed bee colonies and the year-on-year increases in New Zealand are among the fastest in the world.
The 2020 Bee colony report released in March from the Ministry for Primary Industries (MPI) indicates that, as in previous surveys, average colony loss rates over winter were significantly higher for non-commercial beekeepers than for commercial beekeepers.
Variation in the data was acknowledged, but beekeepers with less than 11 colonies were far more likely to report losses from predation and diseases than beekeepers with more than 500 colonies.
Listen to Jamie Mackay interview Dr Jacqueline Rowarth on The Country below:
A third of all colony losses were attributed to queen problems and another third to suspected varroa and related complications, followed by suspected starvation (7.6 per cent) and wasps (6.6 per cent). Losses were also frequently attributed to robbing by other bees (4.4 per cent) and natural disasters (2.7 per cent).
Losses due to suspected toxicity were less than 1 per cent for all sizes of operations – and less than 0.15 per cent for operations with more than 10 colonies.
The implication is that the professional beekeepers have systems and processes in place plus the knowledge to deal with stock management and with agrichemicals.
Knowledge is critical.
Just as with pharmaceuticals and medical devices, pesticides need to be well-regulated and monitored.
This is particularly important for the people who have the most direct contact with the chemicals, such as farmers.
It is therefore reassuring to farmers and agricultural workers that health surveys continue to reveal they have lower rates of cancer than the general population.
The US research investigating the health of almost 800,000 agricultural workers and their families found that main illnesses were hypertension, diabetes mellitus and mental health. Cancer was not found.
In New Zealand cancer incidence in rural areas is 25 per cent lower than in urban areas.
Chemical companies spend time and money evaluating new products to ensure that they work on the target identified, while having no impact on human health and the environment.
Dr Jacqueline Rowarth. Photo / Supplied
In 2016, Phillips McDougall calculated that the cost of research, development and registration for a new crop protection product was over NZ$300 million and the average time for the process was over 11 years.
New products for New Zealand must go through further evaluation to comply with the Hazardous Substances and New Organisms Act (Environmental Protection Authority (EPA)) and the Agricultural Compounds and Veterinary Medicines Act (MPI)).
Three years of testing and trials over multiple seasons and in different regions of the country are required before chemicals are approved for use.
The trials must prove that the products work as described, and they must provide data on residues as well as health and safety.
Costs of the evaluation were estimated in 2015 by Agcarm to be at least $250,000 but often around $750,000.
The evaluations provide reassurance and results from the Total Diet Study (MPI) indicate that the current approval process is sufficient to ensure human safety.
The latest report (2018) states that "The food New Zealanders eat has a high level of safety in regard to chemical hazards" and "exposure to agricultural chemicals and contaminants from food remains low."
Agri-chemicals, when used as directed, assist with providing safe and affordable food.
In New Zealand we have choices of food types produced organically or conventionally and have the comfort of knowing that whatever the production system, the food is (almost always) safe to eat.
- Dr Jacqueline Rowarth, Adjunct Professor Lincoln University, is a farmer-elected director of DairyNZ and Ravensdown. The analysis and conclusions above are her own. jsrowarth@gmail.com
