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Mar 25, 2020 | Blogs, Environmental / Industrial, Food / Beverage | 0 comments
Plant protection products have sowed seeds of controversy within the agricultural, scientific and regulatory communities. Conversations seem to surround the impact of these chemicals on the ecosystem.
Looking at the bee colony collapse disorder, we posted a blog discussing possible stressor neonicotinoids. Herbicides such as glyphosate are also believed to have contributed to the problem.1 If that’s not enough, researchers have added fungicides, such as chlorothalonil, as a probable cause for the decline of the bee population. 2-3 These fungicides have been found in bumblebees and in honeybee hive residues, and have been shown to increase the likelihood of Nosema ceranae infection in honeybees.3-9
I think this quote sums up my thoughts:
It is only recently that regulatory agencies have taken notice and action. The recent chlorothalonil ban by the European Union is the latest example. The regulation set a deadline of November 20, 2019 for all existing stock to be sold or distributed, with a use-up date for all products of May 20, 2020. Switzerland followed suit in December when it issued a statement withdrawing authorization of chlorothalonil products with immediate effect.
So, what is chlorothalonil?
Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) is a broad spectrum non-systematic agricultural fungicide. It is used on a wide variety of food and cereal crops, as well as large grassed areas like golf courses. Available commercially in many different formulations and brand names, it is used to prevent mildew and mold contamination. Chlorothalonil has been used globally for over 50 years and is the world’s most popular fungicide.
Why should your testing labs be concerned about chlorothalonil?
These decisions were taken following the EFSA’s (European Food Safety Authority’s) scientific assessment, which points to concerns around the chemical’s impact on aquatic life and human health. It concluded that the approval criteria were not satisfied for a wide range of reasons.
In a statement, the European Commission said: “There are also serious environmental concerns, notably high risks are identified for fish and amphibians and great concerns are raised concerning contamination of groundwater by metabolites of the substance.” According to the World Health Organization (WHO), chlorothalonil can cause kidney and stomach damage in humans and renal tumors in rodents and dogs. The chemical has been linked to declining bee populations.
While the EU and Switzerland are the first to ban chlorothalonil, the world is watching. Will other countries or regions follow? In the meantime, scientists testing for pesticide residues in food or environmental samples need to be prepared.
What are the limits of chlorothalonil residue testing?
Before prohibition was on the agenda, chlorothalonil was regulated in some markets. This was in the form of legal or advisory maximum residue level (MRL) on chlorothalonil residues and its metabolite SDS-3701.
Where these standards exist, they set concentration limits in agricultural (animal and plant) commodities, as well as soil, groundwater and drinking water. While they vary between countrIES, the Codex Alimentarius Commission serves as a reference for international food trade, with MRL of 0.01 mg/kg upwards depending on the sample type.
With the recent ban coming into force, it’s expected that food and environmental testing will play an important role. This will not only ensure adherence to the ban but also measure its effectiveness. We would expect the food supply, as well as soil and water environments, to be free of residues in due course. Chlorothalonil is moderately persistent, with a half-life ranging from several days to 6 months, even up to 1 year after successive application.
What are the analytical challenges for pesticide residue testing laboratories?
It is important to be aware of the relevant chlorothalonil standards and limits in your region. Ideally, your analytical methods will need to be capable of monitoring this fungicide in all commodity groups with an LOQ of 0.01 mg/kg, and within any regulatory guidelines.
For most labs, this means being able to test for more compounds in a wider range of samples at low concentrations with good accuracy and reproducibility. The keywords here are sensitivity, selectivity and specificity.
How do you achieve sensitive and rapid chlorothalonil analysis?
The prevalence of multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses for the quantification of pesticides in food and environmental samples has been steadily increasing for many years. It is a minimum requirement for most laboratories working in these fields.
Modern tandem quadrupoles can detect regulated compounds at very low levels with minimal sample preparation. They offer a sensitive, simple, robust and rapid simultaneous determination of a wide variety of pesticide analytes in different samples. See what SCIEX pesticide testing solutions can offer. If you have any questions, feel free to comment here or email me at kc.hyland@sciex.com.
References
In a recent webinar, available on demand, scientists Luiza Chrojan and Ryan Hylands from Pharmaron, provided insights into the deployment of capillary gel electrophoresis (CGE) within cell and gene therapy. Luiza and Ryan shared purity data on plasmids used for adeno-associated virus (AAV) manufacturing and data on AAV genome integrity, viral protein (VP) purity and VP ratios using the BioPhase 8800 system.
Last year, Technology Networks hosted two webinars that featured groundbreaking research utilizing SWATH DIA (data-independent acquisition) for exposomics and metabolomics. Researchers Dr. Vinicius Verri Hernandes from the University of Vienna and Dr. Cristina Balcells from Imperial College London (ICL) demonstrated how a DIA approach can be successfully implemented in small molecule analysis using the ZenoTOF 7600 system. Their innovative approaches highlight the potential of SWATH DIA to enhance the detection and analysis of chemical exposures and metabolites, paving the way for new insights into environmental health and disease mechanisms.
For as long as PFAS persist in the environment, there is no doubt they will persist in our conversations as environmental scientists. Globally, PFAS contamination has been detected in water supplies, soil and even in the blood of people and wildlife. Different countries are at various stages of addressing PFAS contamination and many governments have set regulatory limits and are working on assessing the extent of contamination, cleaning up affected sites and researching safer alternatives.
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