• Monitoring data in pesticide registration

      Cornelese A; Boesten JJTI; Leistra M; Linden van der AMA; Linders JBHJ; Pol JW; Verschoor AJ; Alterra; CTB; SEC; et al. (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2003-09-30)
      The Dutch working group for the "Revision of the decision tree leaching" commissioned by the Ministry of Housing, Spatial Planning and the Environment, has worked on the improvement of the decision tree leaching, including triggers, safety factors, scenarios, models, field- en lysimeter studies and monitoring. The guidelines developed by the working group enable a more consistent and comprehensive registration process for pesticide admission. This report deals with monitoring in the decision tree. In the registration process in the Netherlands the precautionary principle will always be followed which implies that a pesticide is not registered until it has been demonstrated that it complies with legal criteria. Monitoring results will be introduced in the final phase of registration. A prerequisite is that the monitoring data comply with generally accepted quality standards and, if applicable, international Good Laboratory Practice protocols. Furthermore the monitoring programmes should be dedicated to the question whether the substance of interest will leach when it is applied according to Good Agricultural Practice. This report gives guidelines for the set-up of monitoring studies and interpretation and evaluation of monitoring data to be used in the registration process. Furthermore guidance for summarising and evaluation of monitoring results is provided.
    • The new decision tree for the evaluation of pesticide leaching from soils

      Linden AMA van der; Boesten JJTI; Cornelese AA; Kruijne R; Leistra M; Linders JBHJ; Pol JW; Tiktak A; Verschoor AJ; Alterra; et al. (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2004-12-01)
      The Dutch decision tree on leaching from soil has been re-designed to be more in line with EU guidelines on the assessment of the leaching potential of substances. The new decision tree explicitly defines reasonable worst-case conditions as the 90th percentile of the area to which a substance is applied. The tree also determines whether the median annual leaching concentration over a period of 20, 40 or 60 years complies with the EU-drinking water limit, with the length of the period depending on the application frequency. The FOCUS Kremsmnster scenario, officially adopted in the Netherlands as the national scenario, is, in the first tier, used to identify substances with a negligible leaching risk, which can then be registered without further assessment. The core of the decision tree is the second tier, in which the spatially distributed model, GeoPEARL, is used to calculate the leaching. The third tier considers the water-saturated zone up to a depth of 10 m below soil surface. As this tier did not need an update, the new approach is expected to have very little influence on the number of registered substances. Comparing the new approach with the old, we found the new first tier to be almost as strict as the old one, at least when the safety factor of 100 was not used, as in the old tree. For substances for which the leaching concentration was calculated at around 0,1 ug dm-3 using the old procedure, GeoPEARL yielded results that were approximately 10 times higher. This difference was mainly due to the annual application of the substances in the new procedure.
    • Persistence of plant protection products in soil; a proposal for risk assessment

      Linden AMA van der; Boesten JJTI; Brock TCM; Eekelen GMA van; Jong FMW de; Leistra M; Montforts MHMM; Pol JW; Linden AMA van der; Alterra; et al. (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2006-05-04)
      Persistence in soil is one of the evaluation aspects of plant protection products. However, except for trigger values indicating persistence in soil, there is no broadly accepted evaluation procedure at the European level and member states use different approaches for the evaluation of persistence in soil at the national level. Until recently, the Netherlands used a cut-off criterion, but the Netherlands Court of Appeal for Trade and Industry (CBb) ruled this to be in contravention of Directive 91/414/EEC. This report proposes tiered procedures for the assessment of persistence in soil. The system considers three protection goals: 1) protection of soil functions relevant to agricultural production, 2) protection of the structure of agro-ecosystems, and 3) protection of the structure of soil ecosystems in general. The procedure distinguishes three trigger values for the half-life for dissipation (DT50) from soil. Substances having a DT50 > 30 days are assessed according to the Functional Redundancy Principle (FRP); i.e. it is evaluated whether soil functions, for example mineralization of organic matter, are affected. Substances having a DT50 > 90 days are assessed also according to the Community Recovery Principle (CRP); i.e. whether the community structure is affected at two years post application. Finally, substances having a DT50 > 180 days are assessed additionally according to the Ecological Threshold Principle (ETP); i.e. whether concentrations in the soil at seven years post last application potentially allow the development of natural ecosystems. The report proposes separate decision schemes for each of the protection goals. In these schemes both the Predicted Environmental Concentrations (PEC) and the ecotoxicological endpoints can be determined using tiered approaches. Exposure concentrations in test systems are essential for deriving ecotoxicity endpoints. Only rarely, all essential information on environmental conditions and substance properties is available for these test systems. The report describes procedures to derive conservative estimates for the exposure concentration. For this, both pore water concentrations and total contents in soil are considered.