HardSPEC: Surface and Ground Water Exposure Model for pesticide registration in Great Britain and Northern Ireland

When you are applying for a pesticide registration in Great Britain and Northern Ireland with a hard surface use, you need to use the model HardSPEC. HardSPEC predicts surface water, sediment and groundwater exposure from herbicide application to hard surfaces.

Background

HardSPEC estimates exposure from herbicide application to hard surfaces. It is used to calculate PECsurface water and PECsediment from professional and amateur uses and PECgroundwater from use on railways. You must provide an assessment using HardSPEC to support the use of products on hard surfaces. Hard surfaces are any man-made impermeable surface such as concrete, asphalt and railway ballast, that are not intended to bear vegetation.

Six exposure scenarios are defined in HardSPEC:

• suburban (domestic use) stream. A surface water stream receiving surface drainage from a suburban catchment
• urban stream. A surface water stream receiving surface drainage via gully pots from an urban catchment
• urban pond. A pond receiving surface drainage via gully pots from an urban catchment
• major road stream. A surface water stream receiving surface drainage via gully pots from a major road in a rural setting. The stream also receives drainage from an adjacent one-hectare agricultural field
• railway groundwater. The abstraction point of a groundwater body that receives herbicides leached from a railway track crossing the groundwater catchment
• railway ditch. A ditch adjacent to a railway embankment. The ditch receives water which has leached through the railway ballast as well as spray drift from spray trains

For home garden uses an assessment using only the domestic use scenario is required. For railway uses, only the railway scenarios need to be used.

The model is accessed at HardSPEC_ 1.5.2-4.4

This new version of the model fixes an error in HardSPEC relating to desorption of substances. The new version does not result in any changes in predicted environmental concentrations. The document ‘Outline of changes in HardSPECV1.5.2-4.3’ (see below under ‘Other resources’) remains applicable to this new version.

Guidance for applicants

Guidance for applicants is available:

• HardSPEC Guidance
• HardSPEC Guidance Appendices
• HardSPEC Summary Guidance
• HardSPEC Refinements

Other resources

• Cranfield Small Catchment Report
• Environment Agency Road Wash Off Study
• Factors affecting the loss of six herbicides from hard surfaces
• Herbicide Partitioning to Concrete Asphalt and Railway Ballast
• Potential Contamination of Surface and Groundwaters Following Herbicide Application to a Railway
• Railway Track Study
• Outline of changes in HardSPEC_v1.5.2-4.3
• Instructions for use of HardSPEC Calibration Module
• Uncertainty and sensitivity analysis of the HardSPEC environmental exposure model for pesticide regulatory assessments