Environmental Fate and Risk Assessments

An environmental risk assessment (ERA) of veterinary medicines after treatment of animals is now a requirement for all new veterinary medicines and for old products at renewal of Market Authorisation. For Europe, the USA, Japan and Australasia, harmonised guidelines have been adopted to carry out these assessments:

• Environmental Impact Assessments (EIA’s) for Veterinary Medicinal Products (VMP’s)-Phase I, VICH GL6
• Environmental Impact Assessments (EIA’s) for Veterinary Medicinal Products (VMP’s)-Phase II Guidance, VICH GL38

These guidelines suggest a stepwise approach as follows:

• Phase I: Assessment of the potential for environmental exposure
• Phase II Tier A: If exposure is significant, further studies on fate and effect required
• Phase II Tier B: If risks still exist then further studies and a risk management strategy are required

Major routes of introduction of veterinary medicinal products (VMPs) into the environment are:

• Direct excretion onto soil / pasture
• Spreading of manure and slurry
• Run off from dips and pour-on formulations
• Direct input of fish medicines (this has a separate set of requirements)

For a Phase I assessment, data on the physical and chemical properties of the VMP, its uses, dose route, frequency of dosing, animal husbandry and routes of excretion into the environment are important factors in the calculation of predicted environmental concentrations (PECs). If the VMP (excluding ecto- and endo-parasiticides) has a PECsoil of <100 mg/kg, no Phase II assessment is required.

At this point information on the degradation of the VMP in faeces or slurry can be used to refine the calculations. This would usually be relevant for animals that are housed. Currently, there is no guideline for this type of study but HLS has considerable experience in their design and conduct and can provide advice appropriate to individual situations.

For a VMP requiring Phase II assessment the following environmental fate studies are recommended at Tier A:

Results from these studies can be used to refine the PECsoil by taking into account degradation in soil and aquatic systems. Also the results from these environmental fate studies can be used to assess the environmental impact on ground and surface water using computer models (PELMO, PEARL, MACRO and PRZM). Groundwater concentrations are of importance in relation to the EU drinking water directive.

At Huntingdon Life Sciences we have extensive experience of performing both the risk assessments for VMPs and the studies that support them.