Excess nitrogen deposition: a stress factor in Dutch plantation forests

Contains fulltext : mmubn000001_161966802.pdf (publisher's version ) (Open Access)Promotores : C. den Hartog en J. Roelofs125 p

Ecosystem Responses to Reduced Nitrogen and Sulfur Inputs into 2 Coniferous Forest Stands in the Netherlands

Contains fulltext : 28972.pdf (publisher's version ) (Open Access

Environmental risk assessment for pesticides in the atmosphere; the results of an international workshop

The Health Council of the Netherlands organised an international workshop on the fate of pesticides in the atmosphere and possible approaches for their regulatory environmental risk assessment. Approximately forty experts discussed what is currently known about the atmospheric fate of pesticides and major gaps in our understanding were identified. They favoured a tiered approach for assessing the environmental risks of atmospheric dispersion of these chemicals, in the first tier a pesticide's potential for emission during application, as well as its volatilisation potential should be assessed. Estimates of the former should be based on the application method and the formulation, estimates of the latter on a compound's solubility in water, saturated vapour pressure and octanol/water partition coefficient. Where a pesticide's potential for becoming airborne exceeds critical values, it should be subjected to a more rigorous second tier evaluation which considers its toxicity to organisms in non-target areas. This evaluation can be achieved by calculating and comparing a predicted environmental concentration (PEC) and a predicted no-effect concentration (PNEC). By applying an extra uncertainty factor the PNEC can be provisionally derived from standard toxicity data that is already required for the registration of pesticides. Depending on the distance between the source and the reception area, the PEC can be estimated for remote areas using simple dispersion, trajectory type models and for nearby areas using common dispersion models and standard scenarios of pesticide use. A pesticide's atmospheric transport potential is based on factors such as its reaction rate with OH radicals. It should be used to discriminate between those compounds for which only the risks to nearby ecosystems have to be assessed, and those for which the risks to remote ecosystems also have to be determined. The participants were of the opinion that this approach is, in principle, scientifically feasible, although the remaining uncertainties are substantial. Further field and laboratory research is necessary to gain more reliable estimates of the physico-chemical properties of pesticides, to validate and improve environmental fate models and to validate the applicability of standard toxicity data. This will increase both the accuracy of and our confidence in the outcome of the risk assessment

The role of scientific advisory bodies in precaution-based risk governance illustrated with the issue of uncertain health effects of electromagnetic fields

Recently, the Health Council of the Netherlands (HCN) published a report on the precautionary principle. The key message was that rather than as a decision rule, the principle should be regarded as a strategy for dealing with uncertainty carefully. We applied these views of HCN to the issue of potential health effects of electromagnetic fields (EMFs), which is characterised by considerable uncertainty. HCN has published several reports on this issue, thereby influencing governmental policy. We will focus on how HCN dealt with uncertainty in its earlier reports on EMF and to what extent that is in agreement with what HCN now refers to as prudent precaution. For comparison, we include in the examination the reports on EMF of HCN's counterpart in Belgium, the Superior Health Council (SHC). SHC urged its government to implement exposure reduction measures, whereas HCN deemed such measures unnecessary. Informed by this analysis we try to draw some lessons on the role of advisory bodies. We conclude that scientific advisory bodies should inform decision-makers rather than guide them towards a particular decision. In case of substantial uncertainty, they should not attempt to offer unequivocal advice on the best policy option. Scientific advisory bodies better present various policy options and describe their potential consequences as well as limits to science. This would stimulate political decision-makers to decide in consultation with stakeholders how venturous or cautious they want to be, given the stakes involved and to choose matching courses of action