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Use of HardSPEC to provide benchmark PECs - PS2226

Description
The HardSPEC model (Hollis et al 2004) for calculating first tier PEC values in surface and groundwater resulting from herbicide use in Hard Surface environments has, since April 2004, been approved for providing data to the Pesticides Safety Directorate (PSD) to support UK regulatory submissions. The model is the first of its kind to be used for this purpose, and, in view of its novelty and the lack of experience in its use, PSD/Defra are currently sponsoring a research project with Cranfield University (PS2221) to enable the model developers to provide ongoing support for issues relating to its use in regulatory submissions. However, because of the previous lack of detailed information on aquatic exposure following use of herbicides on hard surfaces, regulatory users are unsure how to evaluate the exposure output from the model.

The main objective of this proposal is to provide relevant PSD staff with appropriate regulatory information based on the use of HardSPEC to predict the environmental exposure and associated risk assessment for the two sets of 'test compounds' used as examples of step 3 exposure calculations and risk assessments in the FOCUS Surface Water Scenarios report (Linders et al, 2004). This will thus provide a set of 'benchmark data' for Hard Surface uses that can be compared to existing agricultural usage exposure and risk assessment data at the EU level. Chapter 6 of the FOCUS surface water scenarios report provides a set of exposure data using the FOCUS STEP 3 models and scenarios for two series of 'test compounds' 1 to 7 and A to I. The objective of doing this for compounds A to I was to examine the differences in surface water exposure for a set of compounds with different ranges of mobility and persistence, whereas the objective of using compounds 1 to 7 was to compare the resulting risk assessments with those already carried out for a set of real compounds compiled from a set of EPPO compounds created for a risk assessment workshop and from recently completed EU reviews leading to the inclusion of the compounds on Annex I. Tables 6.1-1 and 6.1-2 of the report provide the relevant properties of the test compounds and these data will be used to derive input data for the HardSPEC model. The resulting surface water exposure concentrations for both sets of test compounds will be compared with those resulting from agricultural usage as detailed in the FOCUS surface water scenarios report. The resulting HardSPEC groundwater concentrations will be used to calculate the average annual groundwater concentration, both at the abstraction well and the base of the railway formation, in order to compare with the regulatory end point of 0.1 microgrammes per litre. In addition, HardSPEC surface water exposure concentrations for compounds 1 to 7 will be used to undertake aquatic risk assessments and the results compared to those resulting from agricultural usage as detailed in the FOCUS surface water scenarios report. Results of the project will be presented in a detailed report.

The provision of HardSPEC-derived exposure patterns and associated risk assessments for the test compounds used in the FOCUS surface water scenarios report will provide relevant PSD staff with a series of benchmarks which they can compare with existing EU regulatory data for agricultural usage compounds. Such benchmarks will provide an agricultural use 'exposure scale' against which to assess hard surface use exposure patterns and risk assessments based on the HardSPEC model. This should greatly aid and speed-up their current assessment and decision-making, enabling them to meet their existing targets for approvals in this novel area.
Objective
The main aim of this proposal is to provide relevant PSD staff with appropriate regulatory information based on the use of HardSPEC to predict the environmental exposure and associated risk assessment for the two sets of 'test compounds' used as examples of steps 1, 2 & 3 exposure calculations and risk assessments in the FOCUS Surface Water Scenarios report (Linders et al, 2004). This will be achieved through the following objectives:
1. To use the data in tables 6.1-1 and 6.1-2 of the FOCUS surface water scenarios report (Linders et al, 2004) to parameterise the HardSPEC model (worksheet ‘Herb_props’).
2. To use the data derived in objective 1 to run the HardSPEC model for FOCUS Surface water test compounds A to I and 1 to 7, save the resulting daily time series of PEC’s in surface and groundwater bodies and show the results graphically.
3. For each of the FOCUS test compounds A to I and 1 to 7, produce a set of tables and graphs comparing the PEC’s produced from HardSPEC (objective 2) with those given in sections 6.2, 6.3.1 and 6.3.3 of the FOCUS surface water scenarios report, resulting from agricultural usage of the compounds.
4. To use the HardSPEC-derived exposure data from objective 2 to derive environmental risk assessments for FOCUS test compounds 1 to 7, using the eco-toxicological data from table 6.1-2 of the FOCUS surface water scenarios report.
5. To compare the risk assessments from objective 4 to those detailed in sections 6.3.2 and 6.3.4 of the FOCUS surface water scenarios report, resulting from agricultural usage of the test compounds.
6. To produce a report describing the parameterisation of HardSPEC and the results of the comparisons of exposure concentrations and associated risk assessments for each test compound. The report will include a conclusion section summarising the implications of these comparisons for interpreting aquatic exposure results from the HardSPEC model.

Project Documents
• Final Report : Use of HardSPEC to provide Benchmark PEC’s and associated Risk Assessments in Surface and Groundwater for the Test Compounds used in the FOCUS_SW Report   (956k)
Time-Scale and Cost
From: 2007

To: 2007

Cost: £12,990
Contractor / Funded Organisations
Mr John M Hollis, Dr Andrew CC Craven
Keywords
Decision Support Tools              
Environmental Effects              
Environmental monitoring              
Modelling              
Pest and Weed Control              
Pesticide use              
Pesticides              
Plants and Animals              
Water              
Fields of Study
Pesticide Safety