Is risk-based, sustainable sediment management consistent with European policy?

Abstract

Background, aims and scope

One issue that remains particularly problematic for integrated and sustainable sediment management is that sediment plays differing roles in various sectoral, regulatory and statutory objectives. This means that across Europe, the level of consideration afforded to sediment management has thus far been primarily left to the discretion of individual countries and agencies. One of the consequences of the complex way in which sediments are regulated in Europe, and a possible over-reliance on the precautionary principle, is that there appears to be less regulatory acceptance of risk-based (rather than mass-based or chemical threshold-based) sediment remedial decisions, and thus resistance to some of the risk-based and in situ remedial technologies currently favoured in North America; “presumptive remedies” are being pushed by a number of agencies, and in-place and risk-based management are meeting great resistance. This summary discusses some of the current and emerging European regulations and strategies and their implications for risk-based sediment management.

Conclusions, recommendations and perspectives

There are numerous examples of ex situ remedial strategies in Europe, where sediments are either treated or contained (and increasingly, considered for beneficial use), but very few examples of in situ management. However, the risk-based evaluation of ALL remedial options is entirely consistent with European environmental policy. In fact, in some cases, presumptive removal of sediments can result in greater risks to human health and the environment than management in place, and thus a failure to meet Europe’s ambitious environmental objectives. Decisions that only address a single, sectoral regulatory driver (such as a desire to remove contaminants from a waterbody) may result in a net detriment to the environment. The European Commission has stated that decisions and policies should be continuously evaluated in the light of emerging science and experience, and, where possible, rigorous science-based risk evaluation should take the place of the application of conservative safety factors. Whilst not specifically addressing sediment management, various European Directives and initiatives set out principles for the selection of land-based remedial options that are consistent with a number of international consensus guidance documents on the site-specific, risk-based selection of contaminated sediment remedial options. Although there are numerous technical differences, the fundamental risk- and cost-based principles being applied to land management should be transferable to sediment management decision frameworks. However, whilst the use of risk-based decision criteria is now well-established (either in principle or in practice) in Europe for soil remedial decisions, these principles have not yet been translated to generally applied decision frameworks or guidance for contaminated sediment management in Europe. There is no reason, however, why they should not be.