September 27, 2024 by Iain Wilson

Iain, Adam and Graham, along with colleagues from NiPERA, have recently published a paper detailing a scheme for accounting for natural (or ambient) background concentrations within a tiered risk assessment. The proposed scheme details an approach that can be used for determining whether the site exhibiting an exceedance is a candidate for considering background concentrations, and if so, allows for identification of suitable natural background concentrations based on local surrogate sites for use in the final stage of a compliance assessment. The scheme has been designed to be applied without requiring complex statistical techniques or additional environmental monitoring beyond which is routinely conducted for regulatory purposes.

The scheme utilises three criteria to assess whether the site requires natural background concentrations accounting for the sensitivity of the site and the extent of the exceedance, and three further criteria for assessing whether the site is suitable candidate for considering natural background concentrations based on co-occurring contaminants and location of the site in comparison to industrial outputs and urban areas. If these six criteria are met, there are then a further five criteria for identifying a suitable surrogate site or sites. The paper contains case-studies for three European countries (Cyprus, France and Spain) where the scheme is applied based on an indicative compliance assessments performed according the European guidance for nickel.

The paper is open access and has been published in Integrated Environmental Assessment and Management here: https://doi.org/10.1002/ieam.4988