When considering the presence of pesticides in our environment, you might think about the outside world: soil, groundwater, sediment and crops are all contaminated with pesticide residues. But pesticides are also present in the indoor environment and accumulate in house dust. Researchers from CIEMAT have analyzed 128 dust samples from farmer households and 40 samples from non-farmer households. Results were remarkable: Even samples from non-farmer households contain 57 different pesticides (median). Many of these compounds have been banned from agricultural application in Europe, but can persist in house dust for extensive periods of time.. Not a single sample was free from pesticide residues.
Almost half of the pesticides measured are recognized as highly hazardous, and their presence in indoor dust may be of risk to human health. Potential effects of exposure to these pesticides include reproductive effects and hormone disturbances, irritation of the skin, eyes and respiratory tract, and cancer. Exposure to pesticides can also impact the gut microbiome. People and pets may be exposed to low concentrations of pesticide residues via inhalation of house dust, but also through accidental ingestion. It is estimated that the ingestion of indoor dust is approximately 30 mg/day for adults and 60 mg/day for children. For some compounds, ingestion of dust might be the main route of exposure. 
The scope of contamination
The farmers participating in this study were from 11 different case study sites in SPRINT, located throughout Europe and in Argentina, and the non-farmer participants were neighbours of farmers and ‘consumers’ living further away from farmland in France and Denmark. The participants were asked to collect the dust from their house during a period of a month, via vacuum cleaning. The presence of 198 pesticides was evaluated; 197 compounds were detected in the samples, demonstrating a huge variety of compounds found in house dust. The number of different pesticide residues detected in each sample ranged between 25 and 121 for farmer households and between 36 and 80 for neighbour and consumer households.
Conventional farms using plant protection products exhibited significantly higher numbers of different pesticide residues (80 residues/sample, median) compared to organic farms (65 residues/sample, median) and non-farmer households (57 residues/sample, median), and total concentration was also significantly higher on conventional farms.
Types of pesticide residues detected
17% of the tested compounds were present in more than three quarters of all of the farmer-household samples. Multiple pesticides were even detected in >99% of samples: The insecticides fipronil and imidacloprid, the fungicides fludioxonil, hexachlorobenzene, azoxystrobin, carbendazim, tebuconazole, and a synergist, piperonyl butoxide.
The presence of some of the compounds cannot be explained by recent pesticide applications in the area. Interestingly, imidacloprid and hexachlorobenzene were not approved as a plant protection product at time of this study. However, imidacloprid is often used to treat pets against fleas. In this study, 69% of the farmer participants owned pets, which might explain the high presence of imidacloprid. Hexachlorobenzene has a long field half live, and its presence in dust could reflect historical application of the compound.
Potential human health effects
Glyphosate, pyrethroids and the synergist piperonyl butoxide were found in the highest concentrations. Exposure to these compounds is a risk for human health; Glyphosate and some pyrethroids are possible carcinogens and hormone disruptors and are known to impact the gut microbiome. Piperonyl butoxide is also a known endocrine disruptor and known neurotoxicant. While concentrations of individual pesticides in house dust are relatively low, total concentrations of up to 283 μg/g where measured, which is high compared to other matrices measured in SPRINT. Not much is known about potential health effects of combined exposure to low concentrations of a large number of compounds. Imagine you can handle drinking 4 beers, or 3 glasses of wine, or 1 glass of whiskey, but what would happen if you drank all of them at the same time, every single day? SPRINT researchers are especially interested in elucidating the effects of these ‘cocktails’ on human health, as combined exposure is not taken into account when approving plant protection products for agricultural application. Clarifying these effects can assist future policies for pesticide application. The ultimate goal, of course, is to ensure food availability while protecting human health.
Sources:
Navarro I, De la Torre A, Sanz P, Baldi I, Harkes P, Huerta-Lwanga E, Nørgaard T, Glavan M, Pasković I, Pasković MP, Abrantes N…, Martínez, MA. Occurrence of pesticide residues in indoor dust of farmworker households across Europe and Argentina. Science of the Total Environment. Dec 20;905:167797 (2023). https://doi.org/10.1016/j.scitotenv.2023.167797
Silva V, Gai L, Harkes P, Tan G, Ritsema CJ, Alcon F, Contreras J, Abrantes N, Campos I, Baldi I, Bureau M, Christ F, Mandrioli D, Sgargi D, Pasković I, Polić Pasković M, Glavan M, Hofman J, Huerta Lwanga E, Norgaard T…, Geissen V Pesticide residues with hazard classifications relevant to non-target species including humans are omnipresent in the environment and farmer residences. Environment International. Nov 1;181:108280 (2023) https://doi.org/10.1016/j.envint.2023.108280
Icon credits:
Vacuum, hormone, cancer ribbon: flaticon.com
Inhale icon: Pike Picture from Noun Project
Ingest icon: Andrew Doane from Noun Project
Gut icon: Imron Sadewo from Noun Project
Integrated pest management (IPM) in practice: an overview.
Written by Honor Mackley-Ward
Integrated Pest Management (IPM) is an ecosystems-based approach to managing pests. It emphasises reducing the negative impacts of pest management on agro-ecosystems, through using natural pest control (such as supporting a healthy ladybird population, which helps control aphids), improving crop resilience, and minimising the use of pesticides.
IPM was developed in response to the negative impacts of synthetic pesticide use, which makes it particularly relevant for SPRINT’s work. Synthetic pesticides emerged at scale from technologies developed during the second world war, and led to radical changes in agricultural pest management. However, pesticide resistance amongst target pest species and negative environmental and human health impacts associated with pesticide use soon emerged. By the 1950s, practices which align with the modern principle of IPM were being used to combat these impacts, and the term ‘IPM’ coined in the US in 1967.
Over recent years, the term has been adopted by a broad range of agricultural stakeholders, all supporting its principles. But what is IPM, where did it come from, and what is its significance for the SPRINT project?
Pesticides and Human Health: an Overview
Written by Honor Mackley-Ward
Source: Canva Pro
Pesticides, including herbicides, insecticides, and fungicides, and also known as plant protection products, are used globally in agriculture and a number of other industries. This article explores the interactions between pesticides and human health, a subject at the core of SPRINT’s ongoing work.
In the past year, we have gathered hundreds of samples across the SPRINT case study sites (Click here for more information). Many of these samples will be used in microbiome analyses, including: soil samples, gut samples from fish, fecal samples from humans and livestock, and nasal swabs from humans. We will analyse the composition of microbes in these samples. All of these samples contain millions of bacteria, fungi and other micro-organisms, which in combination, are called the microbiome.
Agricultural pesticide use in Argentina: The extent, the risks, and the challenges
Written by Charlotte Chivers
Argentina is the only non-European case study site included in SPRINT. We included Argentina in our project because it is the main exporter of soy for animal feed in Europe. In addition, this allows us to compare our findings in Europe against those in South America, where pesticides are often applied more frequently and in greater volumes. Argentina, our chosen case study, is the third biggest pesticide user in the world, with only China and the US using more. In addition, several of the pesticides used in Argentina are no longer approved for use across the EU, so this case study will provide insights into the risks of imported chemicals. This article provides an overview of farming in Argentina before examining the extent of pesticide reliance and the potential risks of current usage.
The UK governments’ decision to allow the emergency use of a neonicotinoid: unravelling the complexities
Written by Charlotte Chivers
On Friday 8th January, the UK government decided to allow the use of a neonicotinoid-based pesticide, thiamethoxam in emergencies. They had previously pledged to maintain a ban on this chemical in line with the EU’s stance towards neonicotinoids.
The UK is not the only country to make this decision, with 11 others also permitting the use of this pesticide in emergencies. These countries include Belgium, Denmark and Spain. These are not the first European countries to lift the ban of thiamethoxam on sugar beet fields; France has already lifted their ban on neonicotinoids.
The news headlines and Twitter uproar resulting from this decision suggests that the public are unhappy with this decision.
When medicine feeds the problem: Are pesticides feeding crop pests?
Written by Charlotte ChiversSPRINT recently attended a fascinating talk at the Oxford Real Farming Conference. Researchers from the University of Edinburgh shared their findings surrounding why pesticides may, paradoxically, benefit crop pests. The research was born from the work by a French agronomist, Francis Chaboussou.
Plant protection products: The what, the why and the how
Charlotte Chivers
What are ‘plant protection products’?
The term ‘plant protection product’ refers to ‘pesticides’. These chemicals are used by farmers, gardeners and foresters to protect crops and increase their yields. Pesticides contain active ingredients such as toxic chemicals, plant extracts, pheromones, micro-organisms or viruses for controlling unwanted ‘pests’. These ‘pests’ can include insects (insecticides), fungi (fungicides) or plants (herbicides).
Due to the risks associated with PPPs, European regulations[1] place limits on how they are used. These regulations are based on the risks to human and environmental health associated with the active ingredients of PPPs.
