Hazard Triggers And Comparative Assessment: An Analysis of Policy Options
Swedish System of Comparative Assessment/Substitution
- The philosophy behind the Swedish system is essentially that hazard/risk cannot be quantified in absolute terms but that the hazard or risk posed by different chemicals can be ranked. This allows for a system of comparison that over time will lead to ‘safer’ products. The Swedish system operates around cut-off criteria, which constitute a traffic light system. Products with similar uses are ranked using key end points as in Figure 1 below. The human health criteria are acute and chronic mammalian toxicity, and carcinogenic and reproductive effects. Environmental criteria are soil degradation, soil mobility and bioaccumulation. The actual trigger values (x and y on the example below) are arbitrary and could be amended over time to make ‘standards’ more demanding.
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- In this example products a and b would be phased out as unacceptable. Products d and e would be approved. Product c would be subject to comparative risk assessment and phased out if satisfactory lower risk alternatives (either d or e) existed. Substitution only operates on products in the amber zone and generally only on those towards the ‘top end’ of the amber zone.
- The Swedes claim that the ‘zones’ take some account of risk, although they appear to be largely based on hazard, and that the cut-offs do take account of exposure. Thus it may be open to the manufacturer of product c to reformulate the product or amend the good agricultural practice (GAP) to reduce its ‘ranking’ and remain on the market.
- There are 3 main situations within the approvals system where substitution comes into play: during a review; in considering a new product; and when a new product may displace an existing product or products.
This is probably the simplest and clearest situation. For instance a review could consider all products containing pyrethroid insecticides with similar uses. Higher risk products could be substituted by lower risk products.
- New Products
A new pyrethroid insecticide product would be ranked against existing pyrethroid products with the same use. If it was placed in the amber zone and had worse characteristics than an existing product in the green zone it would not be approved.
- Existing Products
If, in the above example, the new product had better characteristics than an existing product (which was itself in the amber zone) then the existing product would be withdrawn. However, this would not usually be immediate. The Swedish authority would notify the approval holder that the registration would not be renewed when re-registration next fell due (registration is typically for a period of 5 years). Depending on the period left before re-registration, this might provide the opportunity for the approval holder to reformulate or change the Good Agricultural Practice (GAP) to reduce the ‘risk ranking’.
5. The substitution system only compares like with like. It would thus not normally involve replacing a pyrethroid product (with a high acute toxicity to aquatic organisms) with an OP product (with a higher toxicity to mammals) or vice versa. There have been examples where a product has been withdrawn and ‘substituted’ by a non-chemical method of control (e.g. rotation is felt to remove the need for chemical control).
6. The practical impact of substitution is relatively modest. The Swedes estimate that about 10-15% of withdrawals under their review programme were due to substitution. The rest had occurred for commercial reasons or because the product was unacceptable (i.e. in the red zone). It seems likely that the use of the hazard/risk triggers probably removed more products.
7. Resistance management is taken into account. An amber product would not be substituted if it was required as part of a resistant management strategy. Agricultural need appears to be a significant element in the system. Even red zone products may be phased out over a period if there is no suitable alternative immediately available.
8. Now that companies are familiar with the Swedish arrangements they rarely submit applications for products that could fall foul of the substitution principle. This is seen as a positive benefit of the system in that it encourages companies to only seek approval for ‘low risk’ products. Under a ‘conventional’ registration system there is no incentive to develop ‘safer’ products provided they are ‘acceptable’.
9. The Swedish system operates at the level of the product rather than the active substance. However, in the context of Directive 91/414/EEC the Swedes believe that it has to operate at the active substance level. If it were to operate at the product level this would have to be conducted separately by member states and the Swedes are doubtful that this could be made compatible with the harmonisation objectives of the Directive. They appear to essentially favour adapting Directive 91/414/EEC on the lines of Directive 98/8/EC for biocidal products.