Fifth international Fresenius conference discussed the provisions and approaches for assessing exposure to pesticides
On 6 and 7 December, the fifth International Fresenius Conference "Worker, Operator, Bystander and Resident Exposure and Risk Assessment", held in Mainz/Germany, discussed the latest regulatory issues, biological monitoring and risk mitigation.
The organiser was able to win the support of many acclaimed experts from the German and European authorities as well as from overseas government agencies, the research sector and the industry for this conference. The agenda highlighted the current legal situation within the European Union as well as exposure assessments for epidemiological studies. The discussions also covered the current provisions on pesticide labelling set down in the ISO and EN standards.
From BREAM to BREAM3
Clare Butler Ellis of the Silsoe Spray Applications Unit (Bedford/Great Britain) reported on the continued development of the BREAM2 model (BREAM = Bystander and Resident Exposure Assessment Model), which was originally funded by the British government. BREAM2 is used to calculate the exposure to pesticide spray of residents and bystanders.
BREAM2 is a development of the BREAM model which more accurately describes the interrelationship between airborne spray and potential dermal exposure. The guidelines published by the European Food Safety Authority use outputs from BREAM – but Ellis recommended EFSA to use the new BREAM2 model to generate more accurate data.
Ellis also looked ahead to the next generation of the BREAM model (BREAM3). This model could incorporate the advantages offered by technical innovations in connection with the sprayers: For example, nozzles that produce 75% drift reduction, improved boom height control – or the effect of different crop canopies.
Huge dilemma for the risk assessment area: Smallholders pesticide application practiser are not adequately addressed by databases
The real-life situation faced by smallholders, as operators, is a challenge in determining acceptable risk during typical plant protection product use, Curt Lunchick pointed out. Lunchick is responsible for the assessment of domestic and work-related exposure and risks at the Bayer Crop Science Division and Bayer Animal Health in the USA.
The FAO defines small holder farmers as farmers with 2 ha of land or less and sixty percent of all small holder farmers are subsistence farmers. These smallholders often have poor financial opportunities – and often insufficient knowledge about how to use pesticides properly and safely. “While we desire to accurately estimate the exposure to small stake farmers, the operator exposure data that are currently available may not be representative of the application methodology used by smallholder farmers outside of North America and the European Union”, was how Lunchick summed up the dilemma. Pesticides are often sprayed or distributed whilst the users are wearing inadequate clothing – with no protection on their arms and hands. This problem is caused by local customers, the lack of education and information. Operators must be made aware of the dangers and requirements regarding how to use these products.
This less than acceptable behaviour also causes problems for those who plan and develop exposure assessments: “Sometimes we focus on the wrong target”, Lunchick stated whilst indulging in self-criticism. He quoted an example from India. In India, the authorities had been focussing on foot exposure because many farm workers worked barefoot or in sandals. However, 40 to 50 percent of the exposure measured from knapsack application was actually found to be to their backs – the cause most likely being residues left on the sprayer. “The gulf between our guidelines and instructions and actual smallholder practice is becoming increasingly evident. Protecting smallholder farmers is a high priority for the industry and we are now undertaking steps to understand the factors behind this divergence”, was a promise Curt Lunchick made on behalf of the industry.
Under discussion: Use of epidemiological studies in risk assessment practice
Antonio F. Hernández-Jerez from the University of Granada (Spain) discussed the advantages and disadvantages of epidemiological studies in pesticide risk assessment practice. The advantages of being able to examine real-life exposure and not to be dependent on extrapolation is often countered by poor exposure characterisation and inappropriate study design. Hernández-Jerez is nonetheless convinced that epidemiological studies can be valuable for the pesticide hazard identification process: “Biological plausibility can lend support to the epidemiological associations found between pesticide exposure and complex diseases.”