Developments in modelling the exposure of operators to agricultural use of PPP as part of the BROWSE project Rianda Gerritsen-Ebben, Henk Goede, Thies Oosterwijk, Suzanne Spaan, Vicki Roelofs, Marc Kennedy, Richard Glass, Andy Hart, Mark Fee, Agathi Charistou, Kiki Machera, Clare Butler Ellis.

Content of presentation BROWSE project Operator exposure models Introduction Overview of models included Modelling approach Components of the models Example outputs Conclusions

BROWSE project

BROWSE project Bystanders, Residents, Operators and WorkerS Exposure models for plant protection products EU 7th Framework Program, ref January 2011 – 30 June 2014 Total budget 2.6m euro (EU contribution 2m) Objectives: – Review, improve and extend the models currently used in RA of PPPs to evaluate the exposure of operators, workers and bystanders – New model for residents building on previous work – Involve all relevant stakeholders and end users and take account of gender issues and regional differences – Expected impact: contribute to implementation of Regulation (EC) 1107/2009 and Dir. 2009/128/EC on the Sustainable Use of Pesticides.

BROWSE project Partners: Food and Environment Research Agency, UK Alterra-PRI, The Netherlands Benaki Phytopathological Institute, Greece NIAB (The Arable Group), UK TNO, The Netherlands University of Gent, Belgium Universita Cattolica del Sacro Cuore, Italy University of Newcastle, UK 5

Operator exposure models

Introduction Develop a single, new and improved modeling framework, integrating all available exposure data Incorporate recently-generated, high-quality exposure data if available Take explicit account of key factors and mechanisms influencing exposure, account for non-linearity, strengthen estimation where data are limited Use data on operator practices in different Member States to take account of controls & protective equipment Take account of regional & gender differences

Overview of models included ML models: Mixing and loading liquids all applications Mixing/loading solids all applications Application models: Boom spraying Orchard spraying Hand-held spraying in- or outdoors (spray direction and equipment used as sub scenario)

Model development process Review existing models and data Define assessment objectives & scenarios Develop conceptual model Develop mechanistic model Model calibration, refinement & validation (limited) Implementation of final model as software Testing of software with end-users Review by final stakeholder workshop (Oct ‘13)

Modeling approach 1. Collation of available evidence from the literature 2. Statistical (regression, correlation) analyses of available data 3. Identify exposure determinants and allocate effect sizes/distributions 4. Use of experimental data where appropriate 5. Develop mechanistic algorithms 6. Coding the datasets incl. imputation of data 7. Testing of model outputs with data

Routes and mechanisms considered Use of source-receptor model which describes transport of PPP from the source to the receptor (operator) 3 pathways through which PPP can pass: Emission from source Transport between source and operator Transport at operator

Routes and mechanisms considered 3 main routes of exposure Inhalation (via respiratory tract)  from air Dermal (via skin)  deposition from air  transfer from surfaces  direct spills/splashes Ingestion (via mouth)  transfer from hand to mouth Excluded: those coming from secondary sources (e.g. dietary, other operators) and not from direct handling of PPP!

Conceptual model Surface zone Source Local source zone Skin contaminant layer (different body parts) Outer clothing contaminant layer Inner clothing contaminant layer Air zone Bulk zone Respiratory tractOral Respiratory protective equipment Deposition Splashes/impactionSurface contact InhalationIngestionDermal

Examples of Important factors included PPP use characteristics: liquid, solid, % active substance, product dose, etc. Environmental conditions: wind speed Application technique: vehicle set-up, tank volume, presence cabin, spray quality, boom height, width, sprayed area, nozzle maintenance, etc. M/L technique: container size, location, method used

Mixing and loading Source of exposure Release to air Deposition on crops, surfaces, clothing and skin  dermal exposure Inhalation exposure transfer Surface transfer Release to air Inhalation exposure Source of exposure Splashes/ bulk Dermal exposure Deposition

Mixing and loading liquids and solids models Inhalation model: Advanced REACH TOOL (ART) Dermal model: hand and whole body Transport/collection of containers Opening and closing containers Emptying and decanting or weighing/scooping Using premixed containers and measuring jugs

Boom spraying Source of exposure Release to air Deposition on crops, surfaces, clothing and skin Surface transfer Bulk/splashes Dermal exposure

Boom spraying model Inhalation model (I) Local airborne spray emission (ASE) Plume Wake (II) Dispersion to vehicle(III) Dispersion to operator WP 3 model Dispersion model Cabin protection

Boom spraying model Dermal model: hand and whole body Operating the vehicle Stepping into/out of vehicle Other activities (i.e. nozzle maintenance)

Orchard spraying Source of exposure Release to air Deposition on crops, surfaces, clothing and skin Inhalation exposure Surface transfer Bulk/splashes Dermal exposure

Orchard spraying model (i)The airborne spray (ii)Dispersion around the vehicle (Wake and air Refreshment) (iii)Dispersion from spray around the vehicle to operator using cabin efficiencies (If) Inhalation model:

Orchard spraying model Dermal model: hand and whole body Operating the vehicle Stepping into/out of vehicle Other activities (i.e. nozzle maintenance)

Hand held spraying Release to air Deposition on crops, surfaces, clothing and skin Dermal exposure Inhalation exposure Source of exposure Surface transfer

Hand held model Inhalation model: Advanced REACH TOOL (ART)

Hand held model Dermal model: hand and whole body Spray direction: downwards or up-and downwards Equipment: Backpack or lance/gun with fixed or tractor mounted tank The model consists of two pathways of exposure: (i) Deposition of airborne droplets (ii) 1.Contact with the crop 2.Contact with the equipment

Example outputs Boom spraying and Mixing/loading Liquids BROWSE 500 SC Active substance: test, 500g/l Early growth stage cereals Dose: 1 L/ha 20 and 50 Ha No cabin, No PPE

Example outputs

Conclusions New models for different (most common) scenarios integrating all available data Dermal, inhalation and ingestion exposure Exposure values in same range as current models Limited validation  in the future more validation is needed

Benefits of BROWSE operator exposure model Mechanistic approach not dependent on exposure data - have incorporated as much as possible recent data Combines all relevant information (evidence from literature, experimental data, expert opinion) for model development Models can be easily improved and refined with new evidence - easy to update if new information/data becomes available Provides much more detail and options to choose from than current models Provides insight into exposure routes, exposure determinants and controls User friendly software……………….?

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