A relatively large number of pesticides are found in the blood of Dutch farmers and house dust on farms contains no fewer than 144 types of agricultural poison. European standards offer little protection because they do not look at the total health effects of simultaneous exposure to multiple substances. Researchers fear numerous diseases, including Parkinson’s disease, cancer and reduced fertility.
42 percent of Dutch agricultural land is contaminated. Minister Piet Adema (Agriculture) writes this in a letter to the House of Representatives about the deteriorating water quality. The minister refers to pollution with fertilizers, such as nitrogen and phosphate.
But that is not the whole picture, experts say to NU.nl. There is also widespread contamination with pesticides. The extent of this was revealed last month by interim results of a European study led by Wageningen University & Research (WUR). Agricultural poisons not only accumulate in the soil of fields, but also in farms – and in people.
Researchers found a total of 144 different pesticides in house dust in the homes of Dutch farmers. “That is on the high side compared to other European countries,” says professor of soil physics Violette Geissen of WUR. “The concentration of pesticides in water and the amount of substances in the air is also above average in the Netherlands.”
The numbers may be an underestimate. The researchers tested 207 drugs, but there are 500 on the market in Europe.
Decreased fertility and increase in Parkinson’s disease
The consequences can be major, especially for the farmers themselves. According to the European Food Safety Authority (EFSA), 40 percent of the substances found in house dust are “possibly or definitely” carcinogenic. Furthermore, 33 percent of the drugs are potentially endocrine disruptors and 63 percent can affect fertility or lead to abnormalities in unborn children. Those risks depend on the concentration and duration of exposure, says Geissen.
There is another health risk, says neurologist Bas Bloem of Radboudumc: Parkinson’s disease. It is the fastest growing brain disease worldwide. The explosive growth coincides with the increasing use of pesticides.
Bloem expects the results of a study into Parkinson’s disease in the Bollenstreek this year. Most pesticides are used in bulb cultivation.
In 2018, RIVM found a connection with fruit growing in a study among local residents. Two years later, the Health Council pointed to international research that establishes links between the brain diseases Parkinson’s, Alzheimer’s and the muscle disease ALS.
According to the Health Council, too little attention is paid to the effects on the unborn and diseases that only occur years after exposure. The RIVM also points to a possible link between pesticides and leukaemia.
Danger lurks in a cocktail of low doses
The WUR researchers are concerned. Health standards are set per substance. In this way you can stay below the standard for all individual resources, while you should add up the risks.
The Health Council fears that the damage from a cocktail of pesticides is even greater than from the sum of the individual parts. The latter seems to be the case with Parkinson’s, says Bloem.
The EFSA is now investigating whether the authorization policy for pesticides is inadequate. That policy does not look at the effects of a combination of resources.
In a response, a spokesperson for the agricultural and horticultural organization LTO Netherlands says that scientific research into the influence of pesticides on health is important. “It is important for farmers, their employees and families that they can work and live in a safe environment.”
LTO Nederland says it trusts that the pesticides used are “safe for humans, animals and the environment”. But if new research shows that the assessment can be improved, action must be taken, says the spokesperson.
Supply chain also contaminates organic farming
It varies from farm to farm which resources are found in the mix. At conventional farmers there were a minimum of 95 and a maximum of 108 residues in the house dust. They also have relatively high levels of pesticides in their blood and faeces by European standards. This also appears to apply to consumers and local residents.
Fewer pesticides are found on organic farms, but still 65 to 100 residues in house dust. The concentrations in blood and faeces are clearly lower among organic farmers, says Geissen.
Organic farming does not use chemical pesticides. However, these farms can also come into contact with it through the supply chain or surrounding fields.
That supply chain is certainly not clean, says Professor Frank Berendse of Utrecht University. “Imported soy is systematically contaminated. And ships’ holds are treated with the highly toxic cypermethrin to protect the cargo against insect damage.”
“In addition, large amounts of antibiotics still end up in manure, which is spread over almost all fields and pastures.” Berendse fears a connection there with the increase in immune diseases such as asthma, hay fever and MS.
Fine dust and blue-green algae due to nitrogen and phosphate
What about the contamination with fertilizers that Minister Adema was referring to? Agricultural soils are not so much about nitrogen as about phosphate, says Roland Bobbink of research agency B-WARE.
This is because nitrogen can convert into ammonia and can thus move through the air. Phosphate can end up in water from agricultural land. “Half of the water does not meet the phosphate standards,” says Miquel Lurling of WUR. “Under the current policy, this will hardly decrease. The effect can be seen, for example, in the annual return of blue-green algae.”
Blue-green algae is a poisonous bacteria. People can get sick if they swim in water with blue-green algae. Ammonia is also unhealthy, it causes lung complaints due to its conversion to particulate matter.
Pollution increases due to accumulation
The air quality in the Netherlands is poor, but is getting better, the Netherlands Environmental Assessment Agency concluded last week. This is mainly due to sustainable energy and cleaner mobility.
Ammonia and phosphate emissions have also fallen sharply since the 1990s. But that decline has stopped over the past fifteen years, according to the latest figures from Statistics Netherlands.
And while emissions have fallen, total pollution continues to increase. Each year, for example, more than twice as much nitrogen enters the Netherlands via artificial fertilizer and imported animal feed as leaves via agricultural products.
Forty years after ban, DDT is still present in earthworms
A similar problem occurs with pesticides. Total use has fallen slightly over the past ten years, says Berendse. “But the substances used have often become more toxic.”
And because some of the pesticides break down poorly, they also threaten to pile up, says Geissen. She found the commonly used plant killer glyphosate most often in house dust. “This is followed by two substances that are no longer permitted. This shows how persistent some substances are.”
The most extreme example is DDT. This very harmful agricultural poison was banned in the Netherlands in 1973. Buzzards and storks that you hardly saw anymore due to DDT are back in the landscape.
But DDT itself is not gone, and is found in dead godwits, for example. Fifty years after the ban, the meadow birds still ingest the insecticide with every earthworm they collect from the soil.