Maximum permissible and negligible concentrations for metals and metalloids in the Netherlands, taking into account background concentrations

Abstract

The aim of the paper is to provide interested parties the methods that were used for generic hazard assessment in The Netherlands, and the resulting so-called Maximum Permissible Concentrations (MPCs) and the Negligible Concentrations (NCs) for 18 metals and metalloids. The MPCs and NCs were derived for water, sediment, soil and air. The concentration in the environment above which the risk of adverse effects was considered unacceptable to ecosystems is called the MPC. The MPCs take into account that the substances are distributed among the different environmental compartments, and are harmonised accordingly. Included in the MPC and NC are existing background concentrations in The Netherlands following the so-called ‘added risk approach’. The MPCs served as a basis for the Dutch government to set generic Environmental Quality Standards (EQS) in The Netherlands. EQS in turn are used by the Dutch Government to assess the environmental quality and for other environmental policy purposes.Depending on the number of ecotoxicological data, the reliability of the MPCs differed. For water only, MPCs were based on sufficient data, but for the other compartments, there is a great demand for further ecotoxicity data. For soil and sediment, almost no ecotoxicological data were available, and MPCs for those compartments have, in many cases, been derived from MPCs in water applying a modified equilibrium partitioning method (modified EqP-method), resulting in MPCs with greater uncertainty.Some of the methods and underlying assumptions that have been used may warrant further discussion. For example, the lack of data, the factor 100 between MPC and NC, the background concentration, the essential elements, the modified EqP-method and bioavailability, speciation and water chemistry, acid volatile sulfide, and the method that is used for harmonising MPCs for air.Interested parties may use the information and methods on the MPCs and NCs as a general guideline for deriving generic environmental quality standards.